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#1
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Subwoofer physics?
I heard somewhere these statements... are these true (generally):
A low Qts woofer is (generally) better for ported enclosures. A woofer with a large motor structure and magnet stack will (generall) have a lower Qts. Thanks, Garrett |
#2
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Subwoofer physics?
"sanitarium" wrote in message news:1069869994.568057@sj-nntpcache-3... I heard somewhere these statements... are these true (generally): A low Qts woofer is (generally) better for ported enclosures. A woofer with a large motor structure and magnet stack will (generall) have a lower Qts. Thanks, Garrett if you look at modeling software for box building program you'll see that Qts, and EBP give you clues to which box is better for certain subs. not a definite but a guideline |
#3
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Subwoofer physics?
Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people -- Gmac ------------------------------------------------------------------------ Posted via RealCarAudio.com - The checkmate of the caraudio community. http://www.RealCarAudio.com Gmac's Profile: http://www.realcaraudio.com/forums/m...info&userid=10 View this thread: http://www.realcaraudio.com/forums/s...threadid=13774 |
#4
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Subwoofer physics?
"Gmac" wrote in message ... Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people -- Gmac ------------------------------------------------------------------------ Posted via RealCarAudio.com - The checkmate of the caraudio community. http://www.RealCarAudio.com Gmac's Profile: http://www.realcaraudio.com/forums/m...info&userid=10 View this thread: http://www.realcaraudio.com/forums/s...threadid=13774 I was told the mag. size is similar to engine size bigger may look better but may not perform better, look at all the parameters and not just one or two. |
#5
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Subwoofer physics?
It's so true, I've seen subs with huge mags and surrounds that you'd think
would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. "Tha Ghee" wrote in message ... "Gmac" wrote in message ... Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people -- Gmac ------------------------------------------------------------------------ Posted via RealCarAudio.com - The checkmate of the caraudio community. http://www.RealCarAudio.com Gmac's Profile: http://www.realcaraudio.com/forums/m...info&userid=10 View this thread: http://www.realcaraudio.com/forums/s...threadid=13774 I was told the mag. size is similar to engine size bigger may look better but may not perform better, look at all the parameters and not just one or two. |
#6
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Subwoofer physics?
The huge surround actually makes it worse since the cone is a lot smaller
that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. "Tha Ghee" wrote in message ... "Gmac" wrote in message ... Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people -- Gmac ------------------------------------------------------------------------ Posted via RealCarAudio.com - The checkmate of the caraudio community. http://www.RealCarAudio.com Gmac's Profile: http://www.realcaraudio.com/forums/m...info&userid=10 View this thread: http://www.realcaraudio.com/forums/s...threadid=13774 I was told the mag. size is similar to engine size bigger may look better but may not perform better, look at all the parameters and not just one or two. |
#7
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Subwoofer physics?
"Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#8
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Subwoofer physics?
GZ was the only sub I've seen that actually has enough motor to take full
advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message ... "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#9
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Subwoofer physics?
Agree with everything you all have said...
what does GZ stand for? thx, Garrett "Paul Vina" wrote in message news:xNGzb.424316$Fm2.428117@attbi_s04... GZ was the only sub I've seen that actually has enough motor to take full advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message ... "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#10
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Subwoofer physics?
Ground Zero. It's a car version of the Sunfire home audio sub. Really bad
ass. Paul Vina "sanitarium" wrote in message news:1070567321.909493@sj-nntpcache-3... Agree with everything you all have said... what does GZ stand for? thx, Garrett "Paul Vina" wrote in message news:xNGzb.424316$Fm2.428117@attbi_s04... GZ was the only sub I've seen that actually has enough motor to take full advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message ... "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#11
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Subwoofer physics?
if you're challenging the use of half the surround as part of the
effective radiating surface equation, sorry - it's quite true, and an accepted engineering reality. Also, some of those tall skinny edges can be a mother to keep from inverting noisily at excursion limits... I think the IDMax is not necessarily prone to that, but there are reasons why most sub mfr's don't use that approach. JD Tha Ghee wrote: "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#12
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Subwoofer physics?
bah... there's plenty of wide roll subs around with enough motor to take
advantage of the extra mechanical excursion. JD sanitarium wrote: Agree with everything you all have said... what does GZ stand for? thx, Garrett "Paul Vina" wrote in message news:xNGzb.424316$Fm2.428117@attbi_s04... GZ was the only sub I've seen that actually has enough motor to take full advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message .. . "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#13
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Subwoofer physics?
I can't think of any off the top of my head. Of the ones that have enough motor, how many have enough suspension? I could never understand how a manufacturer could have tons oxmax potential and then constrict it with a suspension that won't allow it.
Paul Vina "John Durbin" wrote in message ... bah... there's plenty of wide roll subs around with enough motor to take advantage of the extra mechanical excursion. JD sanitarium wrote: Agree with everything you all have said... what does GZ stand for? thx, Garrett "Paul Vina" wrote in message news:xNGzb.424316$Fm2.428117@attbi_s04... GZ was the only sub I've seen that actually has enough motor to take full advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message ... "Paul Vina" wrote in message news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#14
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Subwoofer physics?
if you're challenging the use of half the surround as part of the effective radiating surface equation, sorry - it's quite true, and an accepted engineering reality.
I'm not challenging that at all. I was simply saying the wider you make the surround the smaller the radiating will be. And you'll have to make up for that decrease with increased stroke. Also, some of those tall skinny edges can be a mother to keep from inverting noisily at excursion limits... I think the IDMax is not necessarily prone to that, but there are reasons why most sub mfr's don't use that approach. I don't doubt it. It took ID forever to get it to work right apparently. Paul Vina |
#15
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Subwoofer physics?
It's a little stupid to design too much roll with not enough motor,
likewise too much motor with not enough roll/mechanical excursion. Of course, it's done all the time - poser subs with single stack motors and giant surrounds for example. That costs next to nothing, also doesn't do much of anything to improve performance or can even hurt it if the loss of Sd isn't made up by any improvement in excursion. But, marketing "wizards" have definitely made that choice in the past in some case, and probably will continue to as long as uneducated consumers buy them. Over-sized motors without enhanced Xsus is really dumb though - it costs $$ to make big motors, and if you don't provide enough mechanical excursion, all you do is create really lousy sounding, easier to break product that cost more - assuming the same distribution costs that is. You would think that kind of mismatch wouldn't happen very much given the cost penalty, but the same mentality that says "let's put a 1,000 HP rat motor in a Vega" is also prone to bolting on too much motor to a frame that can't handle the extra travel, and at that point it doesn't too much matter whether you run out of spider travel, edge travel, or coil former travel - it's going to be limited by the first one of those things it hits regardless of how much Xmax the motor has. But, there are plenty of much better balanced subs out there. JL always has a good balance in their designs... none of our subs are very much off one way or the other as far as Xmax vs. Xsus goes - we've never seen any benefit from getting those two out of whack. The Adire stuff is similar in that respect. Dual Gap (or the Adire split gap) changes the equation somewhat, in that the motor is able to accelerate the moving mass almost as quickly/forcefully at the limits of its stroke as it does from center. That forces you to redefine compliance limits for edges and spiders differently. But, ideally it should still all work together without an excess of motor stroke or mechanical stroke. JD Paul Vina wrote: I can't think of any off the top of my head. Of the ones that have enough motor, how many have enough suspension? I could never understand how a manufacturer could have tons oxmax potential and then constrict it with a suspension that won't allow it. Paul Vina "John Durbin" wrote in message ... bah... there's plenty of wide roll subs around with enough motor to take advantage of the extra mechanical excursion. JD sanitarium wrote: Agree with everything you all have said... what does GZ stand for? thx, Garrett "Paul Vina" mailto news:xNGzb.424316$Fm2.428117@attbi_s04... GZ was the only sub I've seen that actually has enough motor to take full advantage of the double wide surround. But I agree with you about the IDMAX. That's one of the reasons I bought one. Paul Vina "Tha Ghee" wrote in message . .. "Paul Vina" mailto news:i4dzb.286971$ao4.1001404@attbi_s51... The huge surround actually makes it worse since the cone is a lot smaller that with a regular surround and those subs usually don't have enough motor or Xmax to take full advantage of the wide surround anyway. Paul Vina "Luke Hague" wrote in message ... It's so true, I've seen subs with huge mags and surrounds that you'd think would be all badass, but are killed in the low freq. dept. and SQ by a Cerwin Vega 15". Which doesn't have a huge mag or surround. Ghee is correct But as far as magnet stack and motor structure size alot of companies use those to fool people that's why I liked the IDMAX concept of making the surrond tall opposed to the GZ method of making the surrond wide which makes the cone smaller and I don't believe that 40% can be cacualted into cone area. |
#16
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Subwoofer physics?
I think I was addressing that to the other guy's post - may have replied
to the wrong post though. JD Paul Vina wrote: if you're challenging the use of half the surround as part of the effective radiating surface equation, sorry - it's quite true, and an accepted engineering reality. I'm not challenging that at all. I was simply saying the wider you make the surround the smaller the radiating will be. And you'll have to make up for that decrease with increased stroke. Also, some of those tall skinny edges can be a mother to keep from inverting noisily at excursion limits... I think the IDMax is not necessarily prone to that, but there are reasons why most sub mfr's don't use that approach. I don't doubt it. It took ID forever to get it to work right apparently. Paul Vina |
#17
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Subwoofer physics?
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#18
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Subwoofer physics?
"Nousaine" wrote in message
... John Durbin wrote: if you're challenging the use of half the surround as part of the effective radiating surface equation, sorry - it's quite true, and an accepted engineering reality. Half the surround is an engineering rule-of-thumb but many informed sources use one-third. I've checked a few woofers with MLSSA which has a way of estimating Sd comparing successive Vas measurements using a box and added-mass measurements. Using this technique a figure of 1/4 quarter surround is more representative at small-signal levels. While 1/3 to 1/2 "may" be a good rule of thumb at moderate SPL I'm thinking that 1/4 may be more realistic under small signal and VERY large signal conditions. Also, some of those tall skinny edges can be a mother to keep from inverting noisily at excursion limits... I think the IDMax is not necessarily prone to that, but there are reasons why most sub mfr's don't use that approach. JD I've recently tested one of those (I only know of 2 commercial units that use Haystack surrounds) and while I could, with persistence of vision, see the surround wrinkling at full rear stroke it didn't seem to exhibit the 'flubber' noise until well into wrinkle. IOW I've heard many normal roll woofers that cough-up suspension noises well below the level where the surround gets to the wrinkle-stage. Now, Tom I stated something very close to this over at termpro a while back and I got balsted that more than 20-30% should be included but I disagreed. My questions is how can something that's made to be very fexiable push large amounts of air and still remain pliable |
#19
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Subwoofer physics?
if it moves, and it doesn't deform, it displaces air... therefore it
contributes to total displacement. JD Tha Ghee wrote: "Nousaine" wrote in message ... John Durbin wrote: if you're challenging the use of half the surround as part of the effective radiating surface equation, sorry - it's quite true, and an accepted engineering reality. Half the surround is an engineering rule-of-thumb but many informed sources use one-third. I've checked a few woofers with MLSSA which has a way of estimating Sd comparing successive Vas measurements using a box and added-mass measurements. Using this technique a figure of 1/4 quarter surround is more representative at small-signal levels. While 1/3 to 1/2 "may" be a good rule of thumb at moderate SPL I'm thinking that 1/4 may be more realistic under small signal and VERY large signal conditions. Also, some of those tall skinny edges can be a mother to keep from inverting noisily at excursion limits... I think the IDMax is not necessarily prone to that, but there are reasons why most sub mfr's don't use that approach. JD I've recently tested one of those (I only know of 2 commercial units that use Haystack surrounds) and while I could, with persistence of vision, see the surround wrinkling at full rear stroke it didn't seem to exhibit the 'flubber' noise until well into wrinkle. IOW I've heard many normal roll woofers that cough-up suspension noises well below the level where the surround gets to the wrinkle-stage. Now, Tom I stated something very close to this over at termpro a while back and I got balsted that more than 20-30% should be included but I disagreed. My questions is how can something that's made to be very fexiable push large amounts of air and still remain pliable |
#21
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Subwoofer physics?
"John Durbin" wrote in message ... if it moves, and it doesn't deform, it displaces air... therefore it contributes to total displacement. JD well the surround will deform that's what it's made to do otherwise the cone would have little to no movement so it can't displace that much air |
#22
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Subwoofer physics?
sanitarium wrote:
*I heard somewhere these statements... are these true (generally): A low Qts woofer is (generally) better for ported enclosures. A woofer with a large motor structure and magnet stack wil (generall) have a lower Qts. Thanks, Garrett * 1) That's generally true. How low varies with the topology, IMO. Wit flat BL woofers I'd say you have a bit more leeway, but I'd keep i under 0.5 for the most part.\ 2) That's generally true. Although having more slugs does very littl for motor strength, honestly. If you want more motor strength, best wa to do that is to have a larger DIAMETER motor, as that will result in far more dramatic change in motor strength than slapping on a few extr slugs. There's more than one way to get a low Qts, however. For starters using a suspension which is only as stiff as necessary. An excessivel stiff suspension can send the Q skyrocketing pretty easily, which i why a ludicrously stiff suspension is rather pointless, especiall since Fs skyrockets along with it. You can also use a coil with more layers. You want more BL, and you ca either do that by increasing the flux (bigger motor), or by increasin the number of turns of wire in the gap (more layers or smaller gaug wire) Just because a woofer has a big motor doesn't mean it has a low Qts. A I said, an excessively stiff suspension, a thin coil, or a really loos gap can all make the end result far different than looking at the moto alone from the outside might make you suspect. Hope that helps - Warblee ----------------------------------------------------------------------- CarAudioForum.com - Usenet Gateway w/over one million posts online View this thread: http://www.caraudioforum.com/showthr...threadid=16675 |
#23
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Subwoofer physics?
I meant deform as in moving other than back and forth as designed. In
other words, if the surround inverts when you're playing the woofer hard, it probably ain't contributing to output level at all. JD Tha Ghee wrote: "John Durbin" wrote in message ... if it moves, and it doesn't deform, it displaces air... therefore it contributes to total displacement. JD well the surround will deform that's what it's made to do otherwise the cone would have little to no movement so it can't displace that much air |
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