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Post by Boomzilla on Mar 31, 2013 4:29:54 GMT -5
I see that eBay has 12x12x1/4 inch pads of Sorbothane sheeting for $60. Sorbothane, for those of you not familiar with it, is a vicoelastic compound that is a solid but that moves as a liquid under compression. It is excellent at vibration control and damping. It is often used in industry to prevent vibration from affecting sensitive instruments. It has also found commercial use as running shoe inserts because of its shock absorption properties.
It seems to me that cabinet vibration is one of the biggest problems for loudspeakers. Although speaker manufacturers can't afford to put Sorbothane pads in or on their speakers for cost reasons, the consumer could easily use the material to damp a pair of speakers that were otherwise acceptable.
Normally "reverse engineering" a speaker is a slippery slope because when one thing is changed, an avalanche of unintended consequences must also be addressed. Using the Sorbothane pads externally on the largest walls of the speaker cabinets, however, would seem to offer reduced cabinet vibration while not affecting cabinet tuning, crossover tuning, or cabinet volume.
Has anyone tried adding Sorbothane padding to the outside of their speakers? How did you attach it? Did it work?
Thanks - Boomzilla
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Post by Jean Genie on Mar 31, 2013 7:43:09 GMT -5
I must say I've never tried this but I would think any speaker manufacturer selling audiophile speakers at premium prices will have designed/discovered the need to use whatever damping or bracing was needed to make the speaker perform as desired. The cost would be absorbed (pun intended) by the consumer.
Just my $.02
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Post by Boomzilla on Mar 31, 2013 7:58:52 GMT -5
I must say I've never tried this but I would think any speaker manufacturer selling audiophile speakers at premium prices will have designed/discovered the need to use whatever damping or bracing was needed to make the speaker perform as desired... Most use bracing. Some use "sandwich" materials. I think some even use Sorbothane in their sandwich. The speaker manufacturers who use such techniques, though, normally price their speakers at the "upper end" of the continuum. I think that less expensive speakers might also benefit from the material (which manufacturers don't use due to cost). From a consumer standpoint, though, an extra $60 to remove cabinet vibration might be a reasonable expense. After all, I routinely see reviews of speakers in all price ranges up to about $3K to $5K per pair where the published test results show (audible) cabinet vibrations. |
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jlafrenz
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Post by jlafrenz on Mar 31, 2013 8:29:38 GMT -5
Not sure how well it would work because Sorbothane is designed to work with the weight of components. I am sure it would have some general absorption qualities while not under pressure, but how much or how well it would work, I have no idea. Products like Dynamat or Dynaliner are designed specifically for what you are trying to do and should be much less expensive.
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Post by Boomzilla on Mar 31, 2013 8:52:01 GMT -5
I believe that the sorbothane is functional in the same manner as Dynamat, etc. The Sorbo seems to actually be cheaper than the Dynamat that I've seen.
I'm wondering if I need either - could a mass loading with some wood or other weight glued to the outside of a cabinet have the same effect? Obviously, it would change the frequency of oscillation (downward, I'd expect, and by a large amount depending on the added mass), but might not actually damp to the degree that Dynamat/Sorbo would. Whadda'ya think?
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DYohn
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Post by DYohn on Mar 31, 2013 9:29:11 GMT -5
Sorbothane is great for uncoupling things like loudspeakers or turntables from the floor or shelves. It is a fantastic vibration reducer. As far as using it on the inside of an enclosure to damp vibrations, I'm also not so sure it would work well since it requires mass loading and it only works in specific frequency bands depending on the thickness and the loading. www.sorbothane.com/ has a calculator that is revealing. I think an acoustic foam designed to be activated by sound pressure rather than by mass would be a better us of your time and money, like this stuff. |
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Post by Boomzilla on Mar 31, 2013 9:38:27 GMT -5
...As far as using it on the inside of an enclosure to damp vibrations, I'm also not so sure it would work well... [/url][/quote] I was thinking of sticking it on the OUTSIDE of a speaker enclosure? |
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Post by DYohn on Mar 31, 2013 9:51:06 GMT -5
...As far as using it on the inside of an enclosure to damp vibrations, I'm also not so sure it would work well... [/url][/quote] I was thinking of sticking it on the OUTSIDE of a speaker enclosure?[/quote] To what end? If the outside of your speaker enclosure is vibrating enough to cause loss of acoustic energy, then 1) it is a very poorly designed system, or 2) it is SUPPOSED to do that (some enclosures are designed to resonate at specific frequencies to help reinforce system output) or 3) something is broken. In any case, I still don't think sorbothane would be the best solution since it is designed to be used under pressure between two surfaces. Use it on the bottom of a loudspeaker if you want to reduce coupling to the floor/shelf/stand. |
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Post by Boomzilla on Mar 31, 2013 10:19:14 GMT -5
Gotcha.
VERY few enclosures are designed to resonate to reinforce system output (is this a fair statement?)
RARELY is anything on a speaker broken.
MANY enclosures, however, DO vibrate significantly enough to produce audible side effects if the review magazine analyses are correct. The majority of plots I see show significant cabinet vibration at one or more frequencies. The majority of tech tests that I read mention cabinet resonances at various frequencies.
I don't think that this indicates a "very poorly designed system," but rather that the cabinet was built to cost constraints that couldn't allow for better reinforcement.
If this theory is right, then aftermarket cabinet reinforcement or external damping should result in significantly better performance. The majority of customers probably don't care (which is why the cabinet was designed to a price point to start with), but for the few who do care, judicious use of cabinet reinforcement should provide (possibly significantly) better performance from the same driver/crossover set.
Since it's difficult if not impossible to disassemble the "average" speaker cabinet non-destructively, then two improvement paths are available to the owner:
1. Introduce internal material (poly fill, etc.) via the cabinet's port to the INSIDE of the cabinet to reduce vibration and/or
2. Introduce external material to the exterior of the cabinet to reduce wall vibration
What do you think?
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jlafrenz
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Post by jlafrenz on Mar 31, 2013 10:34:38 GMT -5
I don't think that this indicates a "very poorly designed system," but rather that the cabinet was built to cost constraints that couldn't allow for better reinforcement. If a speaker is produced to a price point and and the end performance is impacted in a negative by this, wouldn't you say that it is a poorly designed speaker? |
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DYohn
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Post by DYohn on Mar 31, 2013 11:11:15 GMT -5
Quite a few loudspeakers are designed with tuned enclosures. My favorite is made by a company called Teresonic. I think the Lotus Granada uses a tuned system if memory serves. Also many Tannoy and Celestion products were designed with cabinet resonance to reinforce the low end. But systems that are not designed to vibrate at specific frequencies - the vast majority of commercially available systems - sometimes do, and usually it is a product of inferior materials or cost-cutting design. And I call these poorly designed. As far as what yu read in audio magazines or web sites, please always temper this information with a huge pile of salt. Too many audio "experts" find some effect, blow it completely out of proportion and act like it's the end of the world, then devise all sorts of treatments and tweaks and "fixes" that have about the same cost/benefit ratio as you would have if you used your car to kill a fly by crashing into t tree when the fly was on the front of your car. In the vast majority of cases it's much ado about nothing. But yes, some cheaper or cheaply made loudspeakers vibrate like a dildo when they shouldn't, and my advice to "fix" these is to quickly sell them on Fleabay and get something else that's properly designed and assembled. If they cut those kinds of corners on the enclosure you can bet they also used the cheapest possible crossover components and the drivers are probably operating at the hairy edge of their capability just to reproduce normal program material. Adding something to the outside of an enclosure to reduce vibration could be done. The best thing to use would be 3/4" MDF that is glued to the outside. Using rubber is unlikely to help much, IMO. But you might end up with a pretty unique-looking system.  |
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Post by Boomzilla on Mar 31, 2013 11:12:26 GMT -5
If a speaker is produced to a price point and and the end performance is impacted in a negative by this, wouldn't you say that it is a poorly designed speaker? No. I'd say it was a VERY TYPICAL speaker. No speaker, save the cost-is-no-object model is designed without compromise. The compromises don't mean that the speaker is poorly designed. They only mean that the designer did her/his best with the budget available. On virtually EVERY speaker on the market, compromises WERE made that impacted the end performance in a negative way. Otherwise, every speaker on the market would sound just about the same. The compromises that the designer chooses are those that are hoped will have the least sonic detriment to the end product, but those compromises ARE there, just the same. A very common compromise is to allow the cabinet some vibration since cabinet bracing adds significantly to construction cost. Cabinet size, material, construction, and shape are massaged to minimize vibration, but compromises are always made to reach the target price. That the vast majority of speaker cabinets vibrate, and that their vibrations are detrimental to the sound is not an opinion. It is a fact. The fact can be readily verified by reading the test panels of Stereophile magazine reviews. Speaker after speaker, almost regardless of cost, exhibits cabinet vibrations that the reviewer may (or may not) have heard during the audition. My question in this thread starts with that issue and seeks to answer the question: Can the consumer, with minimal additional cost, correct what the designer could not afford to? |
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Post by DYohn on Mar 31, 2013 11:14:45 GMT -5
Being forced to design using inferior components is what forced me to leave the industry back in 2001. But vibrating cabinets that cause significant loss of energy is a design flaw and indicates poor engineering, and like I said above "fixing" those requires getting rid of them.
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Post by Boomzilla on Mar 31, 2013 11:19:19 GMT -5
Being forced to design using inferior components is what forced me to leave the industry back in 2001. But vibrating cabinets that cause significant loss of energy is a design flaw and indicates poor engineering, and like I said above "fixing" those requires getting rid of them. And since 2001, I somehow don't think that things have gotten better. Cabinets, in fact, do vibrate with significant, frequency-specific energy loss. For the most part, I don't think that this is a design flaw, nor is it an artifact of poor engineering. The companies KNOW that those vibrations are there, and must allow that due to cost constraints. To buy a cabinet that truly minimizes vibration causes compromises in other aspects - less money for drivers, crossovers, connectors, etc. The majority of speaker designers engineer the best speaker they can for a given price point, but don't think that the price point isn't King! Given that the vast majority of us MUST purchase cabinets designed to the desired price point, I again contend that a relatively small amount of after-market-engineering may yield some significant benefits. Do I expect to outsmart the designer? No. What I do plan to achieve, though, is to add enough "budget" to the design to possibly cure some of the most glaring flaws. |
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Post by DYohn on Mar 31, 2013 11:22:14 GMT -5
Just don't get all caught up in the Stereophile "problem of the day" trap. They are trying to sell magazines, not solve your audio issues - unless of course they can create an issue that just happens to be "better" in products sold by their advertisers. |
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Post by Boomzilla on Mar 31, 2013 11:29:26 GMT -5
Just don't get all caught up in the Stereophile "problem of the day" trap. They are trying to sell magazines, not solve your audio issues - unless of course they can create an issue that just happens to be "better" in products sold by their advertisers. You're correct, but Stereophile isn't the issue here. The question of the thread regards cabinet vibration and how/whether to address it after the sale. |
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DYohn
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Post by DYohn on Mar 31, 2013 11:32:55 GMT -5
Just don't get all caught up in the Stereophile "problem of the day" trap. They are trying to sell magazines, not solve your audio issues - unless of course they can create an issue that just happens to be "better" in products sold by their advertisers. You're correct, but Stereophile isn't the issue here. The question of the thread regards cabinet vibration and how/whether to address it after the sale. If you think you need to, then you can. But like I mentioned a couple posts above, I don't think rubber is the right answer. But give it a try, you might love it. |
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Post by Boomzilla on Mar 31, 2013 11:38:39 GMT -5
If you think you need to, then you can. But like I mentioned a couple posts above, I don't think rubber is the right answer. But give it a try, you might love it. You're probably right. Lead plates bolted to the speaker's sides would probably be more effective, but less practical. I was primarily thinking of those huge Klipsch Cornwalls whose cabinets ring like bells. I could encase the entire speakers in a separate external cabinet, but it wouldn't be worth the time or trouble. They're "FleaBay" bound, as you hilariously name it!  And Happy Easter, by the way! |
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Post by Deleted on Mar 31, 2013 12:37:37 GMT -5
When I was younger, my parents had a friend that was very big into audio. I remember he had a set of speakers from Somewhere in Europe that had 2 big slabs of marble, one on top and one on the bottom. It had 4 threaded steel rods in each corner and you tightened the top and bottom of the marble on your speaker to make it totally inert. It was very cool and at the time I remember the speakers being almost 10K and that was in the early 90's. They've since both died and I've never been able to find exactly what they had.
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DYohn
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Post by DYohn on Mar 31, 2013 12:45:42 GMT -5
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