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#41
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Legacy Audio speakers -
On Thursday, September 27, 2012 8:01:35 PM UTC-4, Howard Davis wrote:
It is unreasonable to expect that expensive high-performance speakers like these will not become defective within 20 years if not abused? In a word, Yes! It is unreasonable to _EXPECT_ it. In general, I look at any mechanical device as an equation in several variables being: a) Purpose b) Initial quality c) Cost d) Performance e) Use density So, an electric drill, while a tool has a much different purpose than a hammer. And an Estwing hammer is of a much greater cost than a piece of Chinese Junque, while at a typically substantially higher first cost. It will also likely perform better. I would expect the Estwing to last 20+ years of hard use easily. I would not expect the Chinese hammer to do the same. However, if I hammered one nail per year and only into soft wood, either would likely last beyond my personal need. I would not expect any electric tool to last 20 years of hard use without maintenance. Speakers are the functional equivalent of electrical tools. And have internal components, parts and pieces subject to time (not use) related deterioration - capacitors, speaker surrounds, glues and so forth. Some of which may be relevant, some not. In summary, parts may deteriorate with use, certain types of magnets for one, some by abuse, some by age, some by all three. Further, what constitutes 'abuse' will also change with age. At this time, I have six (6) sets of speakers in use. The newest of which is 25 years old, the oldest of which is 50 years old. The only ones that do not (yet) need or have not had some level of maintenance are the newest (AR M5s as it happens). But all of the others from the Maggies to the AR3as have had maintenance or repairs made to one extent or another from a new ribbon tweeter for the Maggies (my fault and a $140 fix) to a complete rebuild of the crossovers (AR3as), to new surrounds to refinishing the exteriors and installation of new grille-cloth. That it is a hobby means that the normal (to me) care-and-feeding of my audio equipment gives me some pleasure and serves as good therapy. This may not apply to others. Installing new surrounds may be a PITA, but they are cheap and don't take much time. Nothing like peeling raisins or counting sugar.... As only one example. But, if you think you are being ill-used by getting only 20 years out of your speakers - I truly suggest you should build your own. In that way you may have complete control of what goes into them, what you expect from them and the longevity you wish to achieve. There is lots of information out there on how to do it as well. Peter Wieck Melrose Park, PA |
#42
Posted to rec.audio.high-end
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Legacy Audio speakers -
In article ,
Peter Wieck wrote: On Thursday, September 27, 2012 8:01:35 PM UTC-4, Howard Davis wrote: It is unreasonable to expect that expensive high-performance speakers like these will not become defective within 20 years if not abused? In a word, Yes! It is unreasonable to _EXPECT_ it. In general, I look at any mechanical device as an equation in several variables being: a) Purpose b) Initial quality c) Cost d) Performance e) Use density So, an electric drill, while a tool has a much different purpose than a hammer. And an Estwing hammer is of a much greater cost than a piece of Chinese Junque, while at a typically substantially higher first cost. It will also likely perform better. I would expect the Estwing to last 20+ years of hard use easily. I would not expect the Chinese hammer to do the same. However, if I hammered one nail per year and only into soft wood, either would likely last beyond my personal need. While I agree with your premise, I don't think you picked a good example. While I wouldn't expect a cheap Harbor-Freight electric drill from China to last more than a couple of years, even with light use, I would expect that a new US made Porter- Cable electric drill would last many years. I have my father's Porter-Cable drill that he bought, probably back in the 1940's. It survived his use (he built furniture as a hobby) and it survived my childhood abuse (not inconsiderable). When my father passed, that old drill came down to me. It still works fine after more than 60 years. OTOH, I bought a hammer out of a one-dollar tool bin when I first came to California back in the late 1960's. I seem to recall it had a made in Taiwan sticker on it (long since gone). It is the only hammer I've ever owned. It is one-piece, drop forged, with a rubber handle grip. There's nothing to break. The rubber, conceivably, could have deteriorated, I guess, but it hasn't. The hammer works fine, and why wouldn't it? I would not expect any electric tool to last 20 years of hard use without maintenance. Maintenance is required for many mechanical manufactured goods, that's true. But some things not only don't need maintenance, but there's nothing to maintain. This is true of speakers. How does one maintain a speaker? By not abusing it? Well, I suppose you call that maintenance if you stretched the definition of the word somewhat. Speakers can be repaired but not really "maintained" like a car or a washing machine. Speakers are the functional equivalent of electrical tools. And have internal components, parts and pieces subject to time (not use) related deterioration - capacitors, speaker surrounds, glues and so forth. Some of which may be relevant, some not. In summary, parts may deteriorate with use, certain types of magnets for one, some by abuse, some by age, some by all three. Further, what constitutes 'abuse' will also change with age. This is true, yet I know someone who is 83 years old and owns two Electrovoice floor-standing 3-way speaker systems that he bought back in the 1950's. Both still work fine (they don't sound all that good by modern standards, but then they never did.) At this time, I have six (6) sets of speakers in use. The newest of which is 25 years old, the oldest of which is 50 years old. The only ones that do not (yet) need or have not had some level of maintenance are the newest (AR M5s as it happens). But all of the others from the Maggies to the AR3as have had maintenance or repairs made to one extent or another from a new ribbon tweeter for the Maggies (my fault and a $140 fix) to a complete rebuild of the crossovers (AR3as), to new surrounds to refinishing the exteriors and installation of new grille-cloth. That it is a hobby means that the normal (to me) care-and-feeding of my audio equipment gives me some pleasure and serves as good therapy. This may not apply to others. Installing new surrounds may be a PITA, but they are cheap and don't take much time. Nothing like peeling raisins or counting sugar... As only one example. This is repair, not maintenance. But, if you think you are being ill-used by getting only 20 years out of your speakers - I truly suggest you should build your own. In that way you may have complete control of what goes into them, what you expect from them and the longevity you wish to achieve. There is lots of information out there on how to do it as well. In the case of speakers, there are things at play here over which the consumer has no control. I mentioned a few of them a couple of weeks ago on this forum. Glue that attacks the grid wires on older Magneplanars, foam surrounds that deteriorate due to pollutants in the air, cones that dry out due to the low humidity and forced air heat used in many parts of the country, etc. The only recourse here is to replace the damaged components. After 20 years, it's unrealistic to expect the manufacturer to accept the burden of the costs of such repairs, but you'd be surprised at the number of high-end manufacturers who will do just that! Peter Wieck Melrose Park, PA |
#43
Posted to rec.audio.high-end
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Legacy Audio speakers -
Please note the interpolations. Please forgive the snippage.
On Thursday, October 18, 2012 10:48:52 PM UTC-4, Audio_Empire wrote: In article , Peter Wieck wrote: On Thursday, September 27, 2012 8:01:35 PM UTC-4, Howard Davis wrote: It is unreasonable to expect that expensive high-performance speakers like these will not become defective within 20 years if not abused? In a word, Yes! It is unreasonable to _EXPECT_ it. In general, I look at any mechanical device as an equation in several variables being: a) Purpose b) Initial quality c) Cost d) Performance e) Use density So, an electric drill, while a tool has a much different purpose than a hammer. And an Estwing hammer is of a much greater cost than a piece of Chinese Junque, while at a typically substantially higher first cost. It will also likely perform better. SNIP While I agree with your premise, I don't think you picked a good example. While I wouldn't expect a cheap Harbor-Freight electric drill from China to last more than a couple of years, even with light use, I would expect that a new US made Porter- Cable electric drill would last many years. I have my father's Porter-Cable drill that he bought, probably back in the 1940's. It survived his use (he built furniture as a hobby) and it survived my childhood abuse (not inconsiderable). When my father passed, that old drill came down to me. It still works fine after more than 60 years. That is a good thing. But back in the day when I worked for a carpentry sub-contractor, the finest screwguns (Porter-Cable, Milwaukee & DeWalt) lasted perhaps 3 months - and were then sent back to the manufacturer for rebuild.. They ran pretty much 6 hours per day, 5 days a week - not abuse, just extremely heavy use. OTOH, I bought a hammer out of a one-dollar tool bin when I first came to California back in the late 1960's. I seem to recall it had a made in Taiwan sticker on it (long since gone). It is the only hammer I've ever owned. It is one-piece, drop forged, with a rubber handle grip. There's nothing to break. The rubber, conceivably, could have deteriorated, I guess, but it hasn't. The hammer works fine, and why wouldn't it? That is an easy answer to give. With respect, one day try a Vaughn or Estwing hammer, even a Klein. Try it when doing what I would call heavy trim - such as handrails on a deck or some such when each nail must be blunted and a nail-gun just does not cut it. Then, try the Taiwan hammer. A well made, well balanced hammer does not tire the user, does not slip off the nail head and follows the wrist of the user. Either is adequate for the occasional nail. But that is not the point. Almost any speaker is adequate for intercom use - not so much for audio use. I would not expect any electric tool to last 20 years of hard use without maintenance. Maintenance is required for many mechanical manufactured goods, that's true. But some things not only don't need maintenance, but there's nothing to maintain. This is true of speakers. How does one maintain a speaker? By not abusing it? Well, I suppose you call that maintenance if you stretched the definition of the word somewhat. Speakers can be repaired but not really "maintained" like a car or a washing machine. Respectfully, "maintenance" means replacing parts before they break. Apparently your school of maintenance might be "allow it to fail", then replace the failed part. Try that on the timing-belt in an interference engine in a car and you will understand the difference between maintenance and repair. Replacing crossover capacitors before they open (or worse, short) is the functional equivalent of replacing a timing belt. Cleaning pots and connectors is the functional equivalent of an oil-change. Removing dust from drivers, oiling the wood - it comes down to care-and-feeding. Speakers are the functional equivalent of electrical tools. And have internal components, parts and pieces subject to time (not use) related deterioration - capacitors, speaker surrounds, glues and so forth. Some of which may be relevant, some not. In summary, parts may deteriorate with use, certain types of magnets for one, some by abuse, some by age, some by all three.. Further, what constitutes 'abuse' will also change with age. This is true, yet I know someone who is 83 years old and owns two Electrovoice floor-standing 3-way speaker systems that he bought back in the 1950's. Both still work fine (they don't sound all that good by modern standards, but then they never did.) At this time, I have six (6) sets of speakers in use. SNIP But all of the others from the Maggies to the AR3as have had maintenance or repairs made to one extent or another from a new ribbon tweeter for the Maggies (my fault and a $140 fix) to a complete rebuild of the crossovers (AR3as), to new surrounds to refinishing the exteriors and installation of new grille-cloth. Installing new surrounds may be a PITA, but they are cheap and don't take much time. Nothing like peeling raisins or counting sugar... As only one example. This is repair, not maintenance. I respectfully disagree. Between age and materials-choices, things wear out and fail. One may get ahead of the bus and *maintain* prior to failure, or be under the bus and wait until a catastrophic failure takes place and then make a *repair*. I prefer the former over the latter. And using the Surrounds as the example - they give plenty of warning before they fail - and so allow replacement prior to a crisis and _BEFORE_ potential voice-coil damage. But, if you think you are being ill-used by getting only 20 years out of your speakers - I truly suggest you should build your own. In that way you may have complete control of what goes into them, what you expect from them and the longevity you wish to achieve. There is lots of information out there on how to do it as well. In the case of speakers, there are things at play here over which the consumer has no control. I mentioned a few of them a couple of weeks ago on this forum. Glue that attacks the grid wires on older Magneplanars, foam surrounds that deteriorate due to pollutants in the air, cones that dry out due to the low humidity and forced air heat used in many parts of the country, etc. I keep Maggies of a certain vintage and I am well aware of that phenomenon. I keep them out of direct sunlight. Not really a big deal. In my conversations with Magnepan over the years, they have been extremely forthcoming on how to prevent coil separation - and what to do should it start - starting with black 'socks'. IOW, their customer-service has been first-rate, direct, unapologetic, and supportive. Their parts, when needed, have been quite inexpensive relative to their competition. That ribbon tweeter cost me a total of $140, including shipping a 6' PVC tube in both directions (they wanted the core back for rebuild). An AR3a tweeter would run me $80 or so, and the 'core' would be landfill. Paper cones may be easily maintained against 'drying out' - albeit at an initial alteration of the properties of the paper - as I remember, the formula goes something like: 1 part conventional, fresh rubber cement, 1 part conventional fresh contact Cement, 10 parts VM&P Naptha, painted on the cone with a soft brush and allowed to dry for 48 hours in a dust-free environment.. This will soften the paper during the drying process, and add a tiny bit of weight overall - but the alternative is re-coning - an imprecise (relative to cone weight) and painstaking process at least. The only recourse here is to replace the damaged components. After 20 years, it's unrealistic to expect the manufacturer to accept the burden of the costs of such repairs, but you'd be surprised at the number of high-end manufacturers who will do just that! They do, and to my way of thinking, they should not unless it is for a recognized process/materials failure that they coulda-shoulda known - similar to a vehicle recall, or a bad run of parts, or the equivalent. Point being that if they are truly competent and high-end (using Magnepan as an example), you, the rest of the world an I want them to remain in business, supportive of their product and so forth. Expecting them to bleed ad infinitum threatens that survival for no good reason whatsoever. That they _have_ the parts or are willing to _make_ the parts at a reasonable cost and that they are willing to make any repair to any of their speakers, also at a reasonable cost is far more than enough in my opinion. I keep a lot of vintage equipment. And I rebuild a fair amount of it that I have rescued from landfill, junk-piles and/or dusty shelves in the back of repair-shops. I see on a regular basis the difference between 'maintenance' and 'failure', much of that failure being utterly needless - the proverbial pound of care caused by careful avoidance of that ounce of prevention. The simple act of removing a grille-cloth to dust the drivers (yes, dust goes through the cloth) will allow for a visual inspection of things... you get the picture. Sorry for the semi-rant. Peter Wieck Melrose Park, PA |
#44
Posted to rec.audio.high-end
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Legacy Audio speakers -
In article ,
Peter Wieck wrote: Please note the interpolations. Please forgive the snippage. On Thursday, October 18, 2012 10:48:52 PM UTC-4, Audio_Empire wrote: In article , Peter Wieck wrote: On Thursday, September 27, 2012 8:01:35 PM UTC-4, Howard Davis wrote: It is unreasonable to expect that expensive high-performance speakers like these will not become defective within 20 years if not abused? In a word, Yes! It is unreasonable to _EXPECT_ it. In general, I look at any mechanical device as an equation in several variables being: a) Purpose b) Initial quality c) Cost d) Performance e) Use density So, an electric drill, while a tool has a much different purpose than a hammer. And an Estwing hammer is of a much greater cost than a piece of Chinese Junque, while at a typically substantially higher first cost. It will also likely perform better. SNIP While I agree with your premise, I don't think you picked a good example. While I wouldn't expect a cheap Harbor-Freight electric drill from China to last more than a couple of years, even with light use, I would expect that a new US made Porter- Cable electric drill would last many years. I have my father's Porter-Cable drill that he bought, probably back in the 1940's. It survived his use (he built furniture as a hobby) and it survived my childhood abuse (not inconsiderable). When my father passed, that old drill came down to me. It still works fine after more than 60 years. That is a good thing. But back in the day when I worked for a carpentry sub-contractor, the finest screwguns (Porter-Cable, Milwaukee & DeWalt) lasted perhaps 3 months - and were then sent back to the manufacturer for rebuild. They ran pretty much 6 hours per day, 5 days a week - not abuse, just extremely heavy use. OTOH, I bought a hammer out of a one-dollar tool bin when I first came to California back in the late 1960's. I seem to recall it had a made in Taiwan sticker on it (long since gone). It is the only hammer I've ever owned. It is one-piece, drop forged, with a rubber handle grip. There's nothing to break. The rubber, conceivably, could have deteriorated, I guess, but it hasn't. The hammer works fine, and why wouldn't it? That is an easy answer to give. With respect, one day try a Vaughn or Estwing hammer, even a Klein. Try it when doing what I would call heavy trim - such as handrails on a deck or some such when each nail must be blunted and a nail-gun just does not cut it. Then, try the Taiwan hammer. A well made, well balanced hammer does not tire the user, does not slip off the nail head and follows the wrist of the user. Either is adequate for the occasional nail. But that is not the point. Almost any speaker is adequate for intercom use - not so much for audio use. OK, I can't argue with you there. But ease of use, good design is another issue, we're talking about things lasting a long time. That Taiwanese hammer cost me a buck. It has lasted more than 40 years. It works today as well as it did when I first bought it. It might not work AS WELL as a better designed hammer, and probably didn't when it was new, but nonetheless, it has lasted. I would not expect any electric tool to last 20 years of hard use without maintenance. Maintenance is required for many mechanical manufactured goods, that's true. But some things not only don't need maintenance, but there's nothing to maintain. This is true of speakers. How does one maintain a speaker? By not abusing it? Well, I suppose you call that maintenance if you stretched the definition of the word somewhat. Speakers can be repaired but not really "maintained" like a car or a washing machine. Respectfully, "maintenance" means replacing parts before they break. Apparently your school of maintenance might be "allow it to fail", then replace the failed part. Try that on the timing-belt in an interference engine in a car and you will understand the difference between maintenance and repair. Replacing crossover capacitors before they open (or worse, short) is the functional equivalent of replacing a timing belt. Cleaning pots and connectors is the functional equivalent of an oil-change. Removing dust from drivers, oiling the wood - it comes down to care-and-feeding. Also with all due respect, maintenance, of a car, for instance, consists of changing the oil, topping-off the brake fluid, power steering fluid, keeping the tires inflated to the proper pressure, etc. These things MIGHT be to keep the cat from failing in some way, but just as often, it's to increase economy, and improve handling (air in tires, for instance. So maintenance might, in some circumstances be defined as replacing things before they fail, but just as often it means keeping the mechanism in top operating condition for other reasons. Speakers are the functional equivalent of electrical tools. And have internal components, parts and pieces subject to time (not use) related deterioration - capacitors, speaker surrounds, glues and so forth. Some of which may be relevant, some not. In summary, parts may deteriorate with use, certain types of magnets for one, some by abuse, some by age, some by all three. Further, what constitutes 'abuse' will also change with age. This is true, yet I know someone who is 83 years old and owns two Electrovoice floor-standing 3-way speaker systems that he bought back in the 1950's. Both still work fine (they don't sound all that good by modern standards, but then they never did.) At this time, I have six (6) sets of speakers in use. SNIP But all of the others from the Maggies to the AR3as have had maintenance or repairs made to one extent or another from a new ribbon tweeter for the Maggies (my fault and a $140 fix) to a complete rebuild of the crossovers (AR3as), to new surrounds to refinishing the exteriors and installation of new grille-cloth. Installing new surrounds may be a PITA, but they are cheap and don't take much time. Nothing like peeling raisins or counting sugar... As only one example. This is repair, not maintenance. I respectfully disagree. Between age and materials-choices, things wear out and fail. One may get ahead of the bus and *maintain* prior to failure, or be under the bus and wait until a catastrophic failure takes place and then make a *repair*. I prefer the former over the latter. And using the Surrounds as the example - they give plenty of warning before they fail - and so allow replacement prior to a crisis and _BEFORE_ potential voice-coil damage. OK, how do you replace a speaker element BEFORE it fails? How would you even know? If it's something you can hear, then by definition, it has already failed. But, if you think you are being ill-used by getting only 20 years out of your speakers - I truly suggest you should build your own. In that way you may have complete control of what goes into them, what you expect from them and the longevity you wish to achieve. There is lots of information out there on how to do it as well. In the case of speakers, there are things at play here over which the consumer has no control. I mentioned a few of them a couple of weeks ago on this forum. Glue that attacks the grid wires on older Magneplanars, foam surrounds that deteriorate due to pollutants in the air, cones that dry out due to the low humidity and forced air heat used in many parts of the country, etc. I keep Maggies of a certain vintage and I am well aware of that phenomenon. I keep them out of direct sunlight. Not really a big deal. In my conversations with Magnepan over the years, they have been extremely forthcoming on how to prevent coil separation - and what to do should it start - starting with black 'socks'. IOW, their customer-service has been first-rate, direct, unapologetic, and supportive. Their parts, when needed, have been quite inexpensive relative to their competition. That ribbon tweeter cost me a total of $140, including shipping a 6' PVC tube in both directions (they wanted the core back for rebuild). An AR3a tweeter would run me $80 or so, and the 'core' would be landfill. Paper cones may be easily maintained against 'drying out' - albeit at an initial alteration of the properties of the paper - as I remember, the formula goes something like: 1 part conventional, fresh rubber cement, 1 part conventional fresh contact Cement, 10 parts VM&P Naptha, painted on the cone with a soft brush and allowed to dry for 48 hours in a dust-free environment. This will soften the paper during the drying process, and add a tiny bit of weight overall - but the alternative is re-coning - an imprecise (relative to cone weight) and painstaking process at least. The only recourse here is to replace the damaged components. After 20 years, it's unrealistic to expect the manufacturer to accept the burden of the costs of such repairs, but you'd be surprised at the number of high-end manufacturers who will do just that! They do, and to my way of thinking, they should not unless it is for a recognized process/materials failure that they coulda-shoulda known - similar to a vehicle recall, or a bad run of parts, or the equivalent. Point being that if they are truly competent and high-end (using Magnepan as an example), you, the rest of the world an I want them to remain in business, supportive of their product and so forth. Expecting them to bleed ad infinitum threatens that survival for no good reason whatsoever. That they _have_ the parts or are willing to _make_ the parts at a reasonable cost and that they are willing to make any repair to any of their speakers, also at a reasonable cost is far more than enough in my opinion. I agree, but some companies just believe that it's good customer relations, and it doesn't cost them that much. Also, many of these small companies take real pride in their equipment and provide great service to their customers simply because they know that said customers could have bought cheaper wares from some other vendor, but chose to pay extra and buy this company's goods instead. They appreciate the commitment and will often bend over backward to insure the customer's satisfaction. I have an Audio Research SP 15 that I have owned for many years. Recently it developed a popping sound in one channel. I swapped the tubes, and the popping remained. so I contacted AR. they said to box it up and send it back to them. I did just that. I had to pay shipping both ways, but when I got it back, they had changed a number of components and charged me nothing for the repair- even though the preamp in question was almost 25 years old! That's customer service. BTW, that SP-15 is still one of the most neutral-sounding preamps ever made - in spite of it being a tubed component. I keep a lot of vintage equipment. And I rebuild a fair amount of it that I have rescued from landfill, junk-piles and/or dusty shelves in the back of repair-shops. I see on a regular basis the difference between 'maintenance' and 'failure', much of that failure being utterly needless - the proverbial pound of care caused by careful avoidance of that ounce of prevention. The simple act of removing a grille-cloth to dust the drivers (yes, dust goes through the cloth) will allow for a visual inspection of things... you get the picture. Sorry for the semi-rant. While I generally agree that the proverbial "ounce of prevention is worth a pound of cure" is very valid ( I've owned several vintage Italian sports cars), I still say that some things cannot be maintained that way and the only recourse is to fix 'em when they fail. |
#45
Posted to rec.audio.high-end
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Legacy Audio speakers -
Much snippage.
A few points: a) Replacing before failure. Use speaker surrounds as one excellent example.. Those surrounds give plenty of warning prior to failure. Checking them even semi-annually is enough. Similarly the paper cones if so equipped - treating them if they start to seem brittle (again, plenty of warning) will stop the problem dead in its tracks. b) Oil changes vs. belt replacement: A full-service oil-change for my VW TDI costs approximately $140 including parts and labor. Synthetic diesel/ash-rated oil, filter and tire rotation. That is 0.048% of the value of the vehicle. Neglecting it could cost thousands. As to greater efficiency and operational economy, if that were the only reason, it would be a poor exchange - and there would be no reason at all not to keep the original oil in place, just topping up as needed. Do the math: my average economy for my style and type of driving is 36.8 MPG since-new (72,000 miles). Assume per VW an oil change every 10,000 miles, and diesel fuel at $4.10/gallon. Assume a 10% fall-off from dirty oil (less than that most likely). Oil = 6 x $11. Filter at $9. $75 in material -labor at $65. That is 34 gallons of fuel. 271 gallons gets me 10,000 miles at present. Assume 33.12 mpg (10% penalty) for not changing the oil. That comes to 301 gallons of fuel. Cheaper not to change the oil by $16.40. And do this over and over. Then change the engine at 100,000 miles (if not sooner) for $8,000+. Getting to belt replacement: should the timing belt fail on an interference engine, at least a new head will be required - assuming no additional damage. Starting at $2,000 or so. So, that is maintenance. Not repair. Not a wait-until-failure item. Tying it back to speakers: Cones, surrounds, crossovers, contacts, cleaning, proper fusing, occasional fuse replacement (you don't think they wear? Ever watched a fuse running near the blow-point? The element dances!) all are maintenance issues or items prone to wear and/or age. And their eventual failure has nothing to do with OM materials choices, execution or workmanship. It has to do with an electro-mechanical device operating at hundreds to thousands of cycles per second over long periods of time. One more non-speaker example: I am rebuilding a small integrated amp right now that suffered a cascade effect from a single failed 68-ohm, 1/2 watt resistor on the right-channel driver board. The one on the other board is nearly black - that will get replaced too - both with 1-watt units. But had someone actually had a look at these boards before letting out the magic smoke and noticed the blackening resistors, it _all_ could have been prevented by replacing two $0.40 resistors. Now, it is a transistor driver pair, two output transistors, six other resistors and one capacitor, my labor being therapeutic, discounted. OK, David Hafler ran everything at the bleeding edge of failure, so one might be able to blame the maker here for using a 1/2 watt resistor. But that is still not the point. Repeat after me: Cascade effect. That is what I am trying to convey and how to prevent it. It may be a PITA to lift the hood on occasion with audio stuff - and even lifting the hood will not discover everything, but at least give yourself half-a-chance to avoid catastrophic failure. Peter Wieck Melrose Park, PA |
#46
Posted to rec.audio.high-end
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Legacy Audio speakers -
Somewhere on teh intarwebs Dick Pierce wrote:
Howard Davis wrote: "Dick Pierce" wrote in message From the above (thank you!), I take it that claims of greater efficiency for reflex systems based on the use of the acoustic "back wave" from the speaker are not valid; that greater efficiency is due to the characteristics of the driver itself, not the acoustic radiation through the port of the enclosure? That is, in essence, correct: the port is najor contributor to system output when the driver is not, and the driver is the major contributor to system output when the port is not. And the port is the major contributor ONLY over a very narrow band of frequencies, just above the system cutoff frequency. Above and below that, it's output diminishes rapidly. For this and your previous post, thank you Dick. I've read all of that at various times before but after reading your explaination I feel that I understand it better. -- /Shaun. "Humans will have advanced a long, long, way when religious belief has a cozy little classification in the DSM." David Melville (in r.a.s.f1) |
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