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#1
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Old speaker boxes
Hello. I currently have 2 old (about 30 years old), but very nice (made out
of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#2
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Old speaker boxes
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#3
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Old speaker boxes
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#4
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Old speaker boxes
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#5
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Old speaker boxes
Well appearnce won't matter cuz there's a soft covering that is velcroed
over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#6
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Old speaker boxes
Well appearnce won't matter cuz there's a soft covering that is velcroed
over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#7
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Old speaker boxes
Well appearnce won't matter cuz there's a soft covering that is velcroed
over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#8
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Old speaker boxes
Sounds like it was there to prevent 3-year-olds from rolling
marbles into the port opening :-) Once they are in there, just try removing them! You could probably remove them with no problem as long as there are no 3-4 year olds in the house :-) Jebus wrote: Well appearnce won't matter cuz there's a soft covering that is velcroed over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#9
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Old speaker boxes
Sounds like it was there to prevent 3-year-olds from rolling
marbles into the port opening :-) Once they are in there, just try removing them! You could probably remove them with no problem as long as there are no 3-4 year olds in the house :-) Jebus wrote: Well appearnce won't matter cuz there's a soft covering that is velcroed over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#10
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Old speaker boxes
Sounds like it was there to prevent 3-year-olds from rolling
marbles into the port opening :-) Once they are in there, just try removing them! You could probably remove them with no problem as long as there are no 3-4 year olds in the house :-) Jebus wrote: Well appearnce won't matter cuz there's a soft covering that is velcroed over the speakers (classic speaker grill, lol). I was figuring the just removing it would be best since I would have to completly open the case to glue it back on or replace it. But as long as i can be sure that removing it is ok then that's what I think would be easiest. Thanks. "Nelson" wrote in message ... "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. Just a guess from the description, but these sound like bass reflex enclosures, and probably are tuned. I would NOT add more holes, unless you want to lose much of the bass. If the fabric is "slapping" on any part of its support on bass note. you could glue it down, stretch it tighter, replace it, or just lose it, depending on how important its appearance is to you. FWIW Nelson |
#11
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Old speaker boxes
Why not use a couple of PC fan guards over the ports to keep any stay parts
or loose Hamsters :-) from getting in........................ "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#12
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Old speaker boxes
Why not use a couple of PC fan guards over the ports to keep any stay parts
or loose Hamsters :-) from getting in........................ "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#13
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Old speaker boxes
Why not use a couple of PC fan guards over the ports to keep any stay parts
or loose Hamsters :-) from getting in........................ "Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#14
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Old speaker boxes
On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus"
wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#15
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Old speaker boxes
On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus"
wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#16
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Old speaker boxes
On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus"
wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#17
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Old speaker boxes
Jeff Wiseman wrote in message ...
Sounds like it was there to prevent 3-year-olds from rolling marbles into the port opening :-) Once they are in there, just try removing them! :-) :-) Pardon me I, just cannot resist telling you about my grandfather who had a glass bottle made for vodka. It had a flat top with the bottleneck rising from that. For some reason the top was not perfectly flat, but had sunk down a bit at the neck, which made it completely impossible to pour the last drop out of the bottle. I don't think he used that bottle very much... :-) |
#18
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Old speaker boxes
Jeff Wiseman wrote in message ...
Sounds like it was there to prevent 3-year-olds from rolling marbles into the port opening :-) Once they are in there, just try removing them! :-) :-) Pardon me I, just cannot resist telling you about my grandfather who had a glass bottle made for vodka. It had a flat top with the bottleneck rising from that. For some reason the top was not perfectly flat, but had sunk down a bit at the neck, which made it completely impossible to pour the last drop out of the bottle. I don't think he used that bottle very much... :-) |
#19
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Old speaker boxes
Jeff Wiseman wrote in message ...
Sounds like it was there to prevent 3-year-olds from rolling marbles into the port opening :-) Once they are in there, just try removing them! :-) :-) Pardon me I, just cannot resist telling you about my grandfather who had a glass bottle made for vodka. It had a flat top with the bottleneck rising from that. For some reason the top was not perfectly flat, but had sunk down a bit at the neck, which made it completely impossible to pour the last drop out of the bottle. I don't think he used that bottle very much... :-) |
#20
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Old speaker boxes
You should consult a speaker building book.
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#21
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Old speaker boxes
You should consult a speaker building book.
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#22
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Old speaker boxes
You should consult a speaker building book.
"Jebus" wrote in message ... Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. |
#23
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Old speaker boxes
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Bruce Tyler wrote: On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus" wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#24
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Old speaker boxes
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Bruce Tyler wrote: On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus" wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#25
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Old speaker boxes
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Bruce Tyler wrote: On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus" wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#26
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Old speaker boxes
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Bruce Tyler wrote: On Tue, 16 Dec 2003 01:48:27 GMT, "Jebus" wrote: Hello. I currently have 2 old (about 30 years old), but very nice (made out of 2 in. thick wood). However, as many woofers are made today, they have the cone in the back for air to come out. Well these tanks have something like that, but in the front. However, isteand of anything plastic, there's a piece of fabric covering the hole (almost like a small grill). Over time from all the use of the speakers, this cloth has become stretched and causes unwanted vibrations/sound in the bass parts especially. Is it safe to remove this or should i replace the cloth? or should i just replace it with another part? would adding more of these holes produce better sound? Thanks. I would say, by all means cut it away, especially if it is causing a vibration with bass rumble as this is very annoying. It may be possible to fit/add a modern fitting to enhance your bass reflex as 30 years ago, not many speakers really had inverted port fittings like many bass boxes nowadays do.. They simply had holes as ports which still helped but because of better speaker travel in modern bass cones, it is better to have inverted ports to suck out the best of the bass echo... I suppose there is an art to getting the best post size per the box size but the fact that your boxes already have a port, this would be a guide to the needed size... I had a similar experience just a month ago to a few days ago. Here's how... About 12 or 13 years ago I built a pair of speaker boxes. They measured 550mm(H) x 410mm(W) x 300mm(D),, thats about 22"x 16.5"x 12".. They were built from a very dense 1" custom board (not the best wood but nice and solid and I mean "solid" and very heavy for their size) and I put into each of them a 10" bass and a midrange/tweeter approx 3" dia and lined the insides with an a polyester fibre cloth about 2" thich,, similar to what they use in sleeping bags and quilts. They worked really well as all-rounder speakers.. 4 Months ago, right..!!! I hear a funny "furry" gushing sound out of one of these speakers. I looked closely to see that the foam surrounds on the bass cones has literally rotted to the point where I touched them only to see them crumble away before my eyes. The midrange/tweeters suffered the same fate as well - rotten.. I decided to retire these speakers althogether, putting them out in the garage for the time being. I bought a pair of P/A type speakers with 12" bass units in them and replaced the 12" drivers with a better pair. Wow,, what a difference. I was thrilled to bits with the outcome... Well about a month ago I decided to re-use the boxes out in the garrage. I made a template up and cut out bigger holes, so as to fit 12" bass units from the 10" units that were in them before they got the rot.. I bought two more 12" units like in the above modified P/A speakers above. These 12" bass units were so good on their own, that I decided to use them as sub type woofers in the old boxes. They worked exceptionally well,, but,, they had a gaping great big 3" hole in each cabinet where the tweeters sat. Although they acted as a reflex port, they looked an eye-sore so I visited the local electronics store and found some plastic ports of "identical" size. What a stroke of luck. They fitted straight in - no gluing or screwing required,, simply pushed them in nice and tight... These ports are about 4" deep, slightly tapered and somewhat enhanced the bass echo even further. Before, you could feel a definite pout of air from the naked hole as the bass cones moved back and forth. The reflected bass was good but a little "boomie". Now, with the plastic ports, there is little air gust but a lot of deep, rich sound coming from the port... I guess I struck it reasonably correct, by luck... As for your boxes,, I suggest that "if" you can,, try to do something similar. If your boxes are good (and it sounds as if they are),, try not to destroy the essential design and character of them but old and/or tatty bits of fabric will do little to help so it may be a pre-requisite to get rid of the cloth and forge ahead... |
#27
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Old speaker boxes
Sanders wrote in message ...
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) |
#28
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Old speaker boxes
Sanders wrote in message ...
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) |
#29
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Old speaker boxes
Sanders wrote in message ...
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) |
#30
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Old speaker boxes
Sanders wrote in message ...
Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) |
#32
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Old speaker boxes
WOW! This antique technological backwater has been honored with a post from Dick Pierce. I haven't seen a post by Dick for years in any of the groups I frequent, but for my money Dick is easily the most knowledgeable speaker guy I have encountered. I was troubled by the obvious inaccuracies of "Sanders" post, but I don't know enough about speakers to post meaningfully on the subject, thanks to Dick for giving us the straight scoop. Regards, John Byrns In article , (Dick Pierce) wrote: Sanders wrote in message ... Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) Surf my web pages at, http://users.rcn.com/jbyrns/ |
#33
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Old speaker boxes
WOW! This antique technological backwater has been honored with a post from Dick Pierce. I haven't seen a post by Dick for years in any of the groups I frequent, but for my money Dick is easily the most knowledgeable speaker guy I have encountered. I was troubled by the obvious inaccuracies of "Sanders" post, but I don't know enough about speakers to post meaningfully on the subject, thanks to Dick for giving us the straight scoop. Regards, John Byrns In article , (Dick Pierce) wrote: Sanders wrote in message ... Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) Surf my web pages at, http://users.rcn.com/jbyrns/ |
#34
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Old speaker boxes
WOW! This antique technological backwater has been honored with a post from Dick Pierce. I haven't seen a post by Dick for years in any of the groups I frequent, but for my money Dick is easily the most knowledgeable speaker guy I have encountered. I was troubled by the obvious inaccuracies of "Sanders" post, but I don't know enough about speakers to post meaningfully on the subject, thanks to Dick for giving us the straight scoop. Regards, John Byrns In article , (Dick Pierce) wrote: Sanders wrote in message ... Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. Sorry, but this is a load of nonsense on several points: 1. MOST foam surrounds have a lower mechanical compliance or, equivalently, higher mechanical stiffness than typical "rubber" (actually one alloy of polybutdene or another) surrounds. 2. In most resaonble high compliance woofers that one would find in a vented enclosure, the surround is NOT responsible for most of the mechanical stiffness anyway, it's the centering spider. 3. Your analysis that "the speaker must get back to '0' as fast as possible", while it might seem intuitively correct, is wrong. Once you are above the mechanical resonance of the loudspeaker, the driver is MASS controlled, NOT stiffness controlled, as you assert. As such, it is NOT the ability to return to a given position, but the need for acceleration. Now, as we hopefully remember: F = ma Where F is force applied by the voice coil, m is mass of the cone and a is it's acceleration. Notice the complete absence of a stiffness term: the suspension does not playb a dominant role at all over most of the operating bandwidth of the speaker. And it does NOT need to accelerate "as fast as possible," but only at the rate determined by the incoming signal. At resonance, the speaker is predomintly resistance (either mechanical or, for the most part electrical) controlled and ONLY below resonance is it stiffness controlled and only then does the suspension's stiffness play a role. And, at that point, it is only the magnitude of the stiffness that counts. 4. If your assertion were correct, all drivers with high compliance, low stiffness surrounds would have worse transient response than stiffer drivers. Yet drivers with high compliance/low stiffness surrounds, as a general rule, tend to go deeper in the bass, for the simple fact that their mechanical resonances are lower. With a lower mechanical resonance, the badnwidth of the system is wider, and wider band systems, all else being equal, have better transient response, as defined by the fundamental relation: dT * dF = 1/2 where dT is the uncertainty in time and dF is the uncertainty in frequency (e.g. bandwidth). What this fundamentally means is that wider bandwidth systems (large dF) have better transient capabilities than narrow band systems (small dT). 5. Optimally tuned reflex systems do NOT require suspensions with high stiffness, as you claim, they require suspensions of the correct stiffness, which is dependent upon the entire system design. One can (and many people successfully have) designed reflex systems using high-compliance drivers. In, for example, the classical lossless B4 maximally flat alignment, one of the requirements is that the driver compliance be about the same as the driver compliance. That means that if you are designing a system with a large cabinet volume, as a means of positioning your self high on the efficiency side of the efficiency/bandwidth/volume relation, you MUST have a high- compliance driver. Otherwise the driver resonance will be too high, tuning will be significantly compromised and the system will, in fact have fairly dismal transient response, contrary to your assertion. 6. Improvements in transient response of reflex systems can be had by moving in the realm of QB3 alignments, which can only be had with low-Q, low resonance drivers, which is, despite your assertion, contrary to the notion of stiff suspensions. All other things being equal, the stiffer the suspe4nsion, the higher the total Q and the higher the driver resonance. 7. Please explain what the difference is between a "ported speaker" and a "bass reflex speaker." (subtle hint: there isn't any) Surf my web pages at, http://users.rcn.com/jbyrns/ |
#35
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Old speaker boxes
In article ,
Sanders wrote: Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Now that's a bold statement. Thankfully, another poster has addressed it for the rest of us. -- cyrus *coughcasaucedoprodigynetcough* |
#36
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Old speaker boxes
In article ,
Sanders wrote: Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Now that's a bold statement. Thankfully, another poster has addressed it for the rest of us. -- cyrus *coughcasaucedoprodigynetcough* |
#37
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Old speaker boxes
In article ,
Sanders wrote: Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Now that's a bold statement. Thankfully, another poster has addressed it for the rest of us. -- cyrus *coughcasaucedoprodigynetcough* |
#38
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Old speaker boxes
In article ,
Sanders wrote: Foam surrounds and ports will never give accurate response. It only allows for a slower base response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass reflex speakers count on a rigid surround and tuned port to accomplish the same task. John Now that's a bold statement. Thankfully, another poster has addressed it for the rest of us. -- cyrus *coughcasaucedoprodigynetcough* |
#39
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Old speaker boxes
Foam surrounds and ports will never give accurate response.
It only allows for a slower base [sic!!!] response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass-reflex speakers count on a rigid surround and tuned port to accomplish the same task. Pardon my bluntness, but you don't know what the h*** you're talking about. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. "Good" and "bass reflex" is a contradiction in terms. |
#40
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Old speaker boxes
Foam surrounds and ports will never give accurate response.
It only allows for a slower base [sic!!!] response to go lower in a smaller box. To understand that after each note, the speaker must get back to "0" as fast as possible. Foam surrounds need a sealed box to do this. Good bass-reflex speakers count on a rigid surround and tuned port to accomplish the same task. Pardon my bluntness, but you don't know what the h*** you're talking about. To over-simplify it, a properly designed sealed-box woofer is _less_ resonant than a bass-reflex design, and the driver "returns to zero" more quickly. "Good" and "bass reflex" is a contradiction in terms. |
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