poly fill, why then dynamat

leftwinger57

I've had my 2Bs for years now and my 7s for months and both had lilly white thick poly fill. Now, I get the passives have no such fill and that cavity should be free of any acoustic deadener. All say add Dynamat Extreme to all baskets and magnets, but why ? I did and I ran out and got mine for free so it was fun. Did I ever hear the ring back people talk about,not sure but w/ the the Dynamat and BH-5 no such ring back will ever happen.

ZLTFUL

They serve different purposes.
Poly-fill makes the cabinet "look bigger" to the drivers.

BH and Dynamat are for dampening. The stock baskets ring like bells when struck, especially so on the passive baskets. Ring means vibration. Vibration is sound...so that sound can transfer into the driver and effect its overall sound.

Obviously, these are simple explanations but they are the whys.

pitdogg2

I was under the impression that Black hole and the like were also to make that cabinet look bigger also. I'm like others here I Dynamat/secondskin everything inside CD,DVD, preamp and amp.

leftwinger57

I've heard this from Skip and others about Dynamatting other devices. Since it's an insulator of sorts wouldn't said devices run hotter. My Adcom has exterior heat sinks but other amps,sources have vents and if blocked or a cdp which kinda runs warm to begin with isn't that a bad thing. Funny thing I blew a 7amp rail fuse to a speaker out and I could of done the Dynamat thing then but it never came to me. Besides there's like 60 allen type screws to undo the top and that's not happening if I can help it. (exaggerating of course).

F1nut

but other amps,sources have vents and if blocked or a cdp which kinda runs warm to begin with isn't that a bad thing.

You seriously don't know not to block any vents???

leftwinger57

I know enough not to block any vents, just saying there are people out there who just might not realize what they are doing and cook their devices. Meanwhile only my speakers are done and unless I get that glass rack I always wanted I'm not taking my gear apart again for some minimal gain. I/Cs, spkr cable, connectors all yes and done but this not for me just yet. What the ef are we doing up so freaking early ???

pitdogg2

you do not need gobs of it small strips will do wonder's, you're just "deadening" not insulating

drumminman

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

leftwinger57

Drumminman this one I totally disagree on. I did the 3" strips of BH-5 and I was shocked at the way it changed the whole dimension and

musicality of the 2Bs. I was ready to rip it out it was so different then before. I did get used to it but deaden it does and that stuff works as advertised for sure.Passives were redone to cover all surface area

ZLTFUL

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

How so?
BH is designed to dampen resonance and the reason it is placed directly behind the stereo drivers in SDAs is to dampen the cabinet resonance from the rear waves off those drivers.

When Poyfill is added to your enclosure, the airspring within the box begins an isothermal process. When the air passes through the Polyfill it is scattered and dissipated by the fibers, causing the air to be less dense. The speaker then interacts with the enclosure as if it is larger than it really is, changing the sound.

Black Hole 5 on the other hand is a visco-elastic damping material. Its key functions are absorption, isolation and damping. It interacts with the sound waves in a completely different manner by absorbing them.

BH even states flat out that their products are for dampening, not dispersion...
http://blackhole-america.com/

vmaxer

ZLTFUL wrote: »

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

How so?
BH is designed to dampen resonance and the reason it is placed directly behind the stereo drivers in SDAs is to dampen the cabinet resonance from the rear waves off those drivers.

When Poyfill is added to your enclosure, the airspring within the box begins an isothermal process. When the air passes through the Polyfill it is scattered and dissipated by the fibers, causing the air to be less dense. The speaker then interacts with the enclosure as if it is larger than it really is, changing the sound.

Black Hole 5 on the other hand is a visco-elastic damping material. Its key functions are absorption, isolation and damping. It interacts with the sound waves in a completely different manner by absorbing them.

BH even states flat out that their products are for dampening, not dispersion...
http://blackhole-america.com/

Well said, that is what I thought but wasn't certain.

On3s&Z3r0s

ZLTFUL wrote: »

They serve different purposes.
Poly-fill makes the cabinet "look bigger" to the drivers.

BH and Dynamat are for dampening. The stock baskets ring like bells when struck, especially so on the passive baskets. Ring means vibration. Vibration is sound...so that sound can transfer into the driver and effect its overall sound.

The "basket ring" argument for Dynamat has always seemed specious to me. It's true, if you hold a stock driver you have removed by the magnet and flick the rim you'll get a ring. Now try holding it firmly all around by the rim and flick the rim. Still hear the same ring? Try bolting it firmly by each fastening point to a solid surface and flick it. Still ringing? That's not how bells or driver baskets work. They don't ring if the bell end is clamped to something, they thunk, which is the same thing that happens if you wrap the baskets in Dynamat or just simply attach them to the front baffle.

I was curious, so I did some critical listening with some drivers in smaller speakers after first changing the mounting hardware (hurricane nuts instead of wood screws) and then adding the Dynamat in a separate step. In the interest of full disclosure, I also used Super Polydent on the driver magnets at the same time I did the hurricane nuts. (Just kidding, I used Loctite PowerGrab, which I think is just a stronger version of Polydent.)

On a pair of smaller speakers (Monitor 5jrs), neither made any sonic difference (wood screws weren't stripped and original gaskets were in good shape). Hurricane nuts are so nice to work with and never a concern for stripping no matter how many times you pull a driver. I would use them any time I touched a speaker.

Dynamat? I can't say it makes zero difference, but as compared with almost anything else you could do to the speaker, I am totally comforable in saying this is absolutely the last inch of the last mile. The amount of polyfill can make a big difference in the way your bass sounds. The amount of Blackhole 5 you use (if you're using it) can make an enormous difference. Be prepared to tune the amount of that almost obsessively if you want to get the best bass out of your speakers. Use the Dynamat only if you are very bored and have spare Dynamat lying around. I could see an argument for Dynamat on the case of something with moving parts prone to vibration like a CD player. Dynamat inside an amp? Again, if you have more time and spare change than you know what to do with, knock yourself out. There are several wires inside your amp and between your components. Do you Dynamat those too? They are going to vibrate way more.

Also, based on direct experience, Blackhole5 and Polyfill do not work the same. BH5 is something you would use instead of adding more bracing to the speaker cabinet (for dampening and reducing the effect of standing waves within the cabinet). And polyfill, as others have mentioned, has a similar effect as if you had put the same drivers in a larger cabinet (in my experience it makes the bass sound bigger and boomier). This may be wrong, but if I add more than the stock amount of polyfill to a pair of Polks I usually also add at least a little BH5. The polyfill seems to make bigger bass and the BH5 seems to tighten the bass, but too much will mute the bass. Allowing the polyfill to slide down between the mid-woofers and the passive radiators will also mute the bass. That's just my experience, I'll take no offense if others contradict or correct.

F1nut

I get what you're saying, but on the other hand one of the reasons a lot of modern driver baskets are cast aluminum these days is because stamped steel baskets are known to still ring a bit when mounted. A steel basket with Dynamat applied sounds totally dead compared to one without. Granted, it's a small tweak, but the effect is cumulative.

Nightfall

On3s&Z3r0s wrote: »

The "basket ring" argument for Dynamat has always seemed specious to me. It's true, if you hold a stock driver you have removed by the magnet and flick the rim you'll get a ring. Now try holding it firmly all around by the rim and flick the rim. Still hear the same ring? Try bolting it firmly by each fastening point to a solid surface and flick it. Still ringing? That's not how bells or driver baskets work. They don't ring if the bell end is clamped to something, they thunk, which is the same thing that happens if you wrap the baskets in Dynamat or just simply attach them to the front baffle.

This was my thoughts and findings too. I don't want to hunt the thread where I stated this but F1Nut said, even though, it was still worthwhile to do it.

On3s&Z3r0s

Nightfall wrote: »

On3s&Z3r0s wrote: »

The "basket ring" argument for Dynamat has always seemed specious to me. It's true, if you hold a stock driver you have removed by the magnet and flick the rim you'll get a ring. Now try holding it firmly all around by the rim and flick the rim. Still hear the same ring? Try bolting it firmly by each fastening point to a solid surface and flick it. Still ringing? That's not how bells or driver baskets work. They don't ring if the bell end is clamped to something, they thunk, which is the same thing that happens if you wrap the baskets in Dynamat or just simply attach them to the front baffle.

This was my thoughts and findings too. I don't want to hunt the thread where I stated this but F1Nut said, even though, it was still worthwhile to do it.

Honestly, I keep putting Dynamat on all the drivers I touch and especially the big PRs too, but just cause I have a extra lying around. That stuff definitely made a huge difference in quieting down my dishwasher. If I still used a CD player in my 2-channel system I'd use it there too. I really don't think I believe the amp thing though. I'll definitely save what I have left in case I ever get another pair of Polks with big PR's. I can imagine I may have been able to hear a difference in the bass if I had done a good before and after listen with those. I think Polk even used to glue some cardboard onto the back of their later PRs to dampen ringing or reflected waves. Some of my PRs have that and some don't. Someone must have eventually decided that was a good tweak even for the stock parts.

On3s&Z3r0s

DSkip wrote: »

On3s&Z3r0s wrote: »

Nightfall wrote: »

On3s&Z3r0s wrote: »

The "basket ring" argument for Dynamat has always seemed specious to me. It's true, if you hold a stock driver you have removed by the magnet and flick the rim you'll get a ring. Now try holding it firmly all around by the rim and flick the rim. Still hear the same ring? Try bolting it firmly by each fastening point to a solid surface and flick it. Still ringing? That's not how bells or driver baskets work. They don't ring if the bell end is clamped to something, they thunk, which is the same thing that happens if you wrap the baskets in Dynamat or just simply attach them to the front baffle.

This was my thoughts and findings too. I don't want to hunt the thread where I stated this but F1Nut said, even though, it was still worthwhile to do it.

Honestly, I keep putting Dynamat on all the drivers I touch and especially the big PRs too, but just cause I have a extra lying around. That stuff definitely made a huge difference in quieting down my dishwasher. If I still used a CD player in my 2-channel system I'd use it there too. I really don't think I believe the amp thing though. I'll definitely save what I have left in case I ever get another pair of Polks with big PR's. I can imagine I may have been able to hear a difference in the bass if I had done a good before and after listen with those.

Why do you not feel it would generate any improvements on your amp? Anywhere that noise can get into your system is going to be a detriment to your sound quality. Vibrations in the chassis will bleed into the components and make themselves known. You've got the stuff laying around - just try it man. I went so far as to throw it in my power conditioner too, just in case. I really don't know if it helped in that application, but I've noticed differences in my source/pre/amp all alike.

The top cover of my amp is pretty much all vent holes, so I could only put it on the sides & bottom. My sense of adventure isn't enough to overcome my gut instinct that it just wouldn't accomplish anything and the stuff could be put to better use elsewhere.

I've heard Wilson (and others) encase their XO components in epoxy to prevent the possibility of any vibration. This seems completely reasonable to me, but thinking an amp is subject to the same kind of vibration or that Dynamat on the case is going to do the same thing as putting everything in epoxy (which I get that you couldn't do with an amp because of heat) just runs counter to my sense of reason and economics.

But, as I get more spare time and coin my attitudes change, so who knows what I might be slapping the Dynamat on 5 years down the road.

F1nut

With amps it all depends, some like the cover panel on my main one is basically all vent slots, but it's really thick aluminum, so pretty dead already. In fact, I couldn't put Dynamat anywhere inside as it's packed wall to wall, not to mention the heat just at idle. Other amps with thin steel covers I at least put some on the sides. Now, my SACD players have Dynamat anywhere I can stick it including the transport.

F1nut

That stuff definitely made a huge difference in quieting down my dishwasher.

Mine's not very old and is pretty quiet, but I might have to try that anyway. Did you put it on the door only? I have considered putting it on the panels of my washing machine, but haven't found the motivation yet.

ZLTFUL

I agree that a basket firmly attached to a baffle *shouldn't* ring. But it still does.
Take for example a stainless steel sink. Clamped and epoxied around the edges to a granite counter top would be the same thing right? Then why does the sink still have an audible ring to it when you flick it?
The baskets will still ring firmly clamped to the baffle and the larger the basket, the more apparent it will become, which is also why I qualified my above statement especially with the larger baskets of the passives.

The larger the free floating surface area, the larger amount of surface you will have to clamp to reduce the ringing. The baskets still vibrate when clamped. Adding dynamat to them helps damp the vibration of those free floating areas.

drumminman

ZLTFUL wrote: »

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

How so?
BH is designed to dampen resonance and the reason it is placed directly behind the stereo drivers in SDAs is to dampen the cabinet resonance from the rear waves off those drivers.

When Poyfill is added to your enclosure, the airspring within the box begins an isothermal process. When the air passes through the Polyfill it is scattered and dissipated by the fibers, causing the air to be less dense. The speaker then interacts with the enclosure as if it is larger than it really is, changing the sound.

Black Hole 5 on the other hand is a visco-elastic damping material. Its key functions are absorption, isolation and damping. It interacts with the sound waves in a completely different manner by absorbing them.

BH even states flat out that their products are for dampening, not dispersion...
http://blackhole-america.com/

According to what you posted from the BH website, BH 5 is designed to reduce vibrations, and provide acoustical damping. It's not supposed to provide vibration control. The resonance control it provides is a result of absorbing the back wave coming off the MW's, and not allowing it to reflect off the back wall back to the MW's, which would cause a form of distortion.

What I heard after installing it in my SDA's was greater mid range clarity and definition.

Lew, you may have put too much BH in. Others here on the forum have experienced a deadening of sound when using too much. One three inch wide strip behind each MW is what I used, and only to the bottom of the lowest MW. If it extends down into the part of the cabinet occupied by the PR, it will kill the bass too.

ZLTFUL

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

This is the quote I was referring to with my response.
Being a visco-elastic damping material, vibration control very much is what it does. resonance is a form of vibration. Heck, sound is a form of vibration.
But it is all semantics.
The point I was debating was where you said it makes the cabinet appear larger to the drivers which is simply not the case.

On3s&Z3r0s

F1nut wrote: »

That stuff definitely made a huge difference in quieting down my dishwasher.

Mine's not very old and is pretty quiet, but I might have to try that anyway. Did you put it on the door only? I have considered putting it on the panels of my washing machine, but haven't found the motivation yet.

I did put a little on the door, but it's a mid-range Bosch and the door was pretty well insulated already. Mostly the noise from inside the dishwasher seems to be from the water jets, and that wasn't too bad. What made a big difference on mine was the fact that the pump motor is under the washer compartment, and there was just a thin metal flashing/cowling between the motor and the cabinet kick plate. Putting Dynamat on that flashing made a big difference in the amount of noise from the motor.

F1nut wrote: »

With amps it all depends, some like the cover panel on my main one is basically all vent slots, but it's really thick aluminum, so pretty dead already. In fact, I couldn't put Dynamat anywhere inside as it's packed wall to wall, not to mention the heat just at idle. Other amps with thin steel covers I at least put some on the sides. Now, my SACD players have Dynamat anywhere I can stick it including the transport.

Eliminating mechanical noise from mechanical component like a disc player makes total sense to me. I have a solid state amp, so other than the back plate connections it doesn't seem like too much should be subject to vibration. But down the road when I have run out of other stuff to tweak I might try isolation feet for the amp. That seems like a more easily removable or repurposable tweak that I would think should have a similar effect to sticking Dynamat on the case.

F1nut

Mostly the noise from inside the dishwasher seems to be from the water jets

Same here and most of that noise comes through the vent at the top of the door.

What made a big difference on mine was the fact that the pump motor is under the washer compartment, and there was just a thin metal flashing/cowling between the motor and the cabinet kick plate. Putting Dynamat on that flashing made a big difference in the amount of noise from the motor.

Ok, thanks. I'll have to take a look down there to see what's what.

On3s&Z3r0s

ZLTFUL wrote: »

I agree that a basket firmly attached to a baffle *shouldn't* ring. But it still does.
Take for example a stainless steel sink. Clamped and epoxied around the edges to a granite counter top would be the same thing right? Then why does the sink still have an audible ring to it when you flick it?
The baskets will still ring firmly clamped to the baffle and the larger the basket, the more apparent it will become, which is also why I qualified my above statement especially with the larger baskets of the passives.

The larger the free floating surface area, the larger amount of surface you will have to clamp to reduce the ringing. The baskets still vibrate when clamped. Adding dynamat to them helps damp the vibration of those free floating areas.

I have to agree with you here... to a point. I have a stainless steel sink, and I put Dynamat on the bottom of it after some other sound deadening material the installers used peeled off because of the heat from dumping pasta water in it. (Who woulda thought the Polk Forum could be so useful for kitchen tweaks. ) But my sink is a huge continuous thin metal surface without any reinforcing ribs stamped in as opposed to driver or passive baskets.

In the world of everything matters and larger speakers I get that it could make a small but discernible difference. In the small speakers I happened to pay the closest attention to while tweaking step-by-step I couldn't hear anything. I have another pair of 2B's that I will do the same to, just to satisfy my curiosity. Mostly I was just saying there were several things that made a very obvious difference in the bass, like the amount of polyfill and BH5, and the Dynamat was just not obvious.

Nightfall

Dynamatting sinks and dishwashers. I love it. Kitchen mods.

drumminman

ZLTFUL wrote: »

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

This is the quote I was referring to with my response.
Being a visco-elastic damping material, vibration control very much is what it does. resonance is a form of vibration. Heck, sound is a form of vibration.
But it is all semantics.
The point I was debating was where you said it makes the cabinet appear larger to the drivers which is simply not the case.

I suppose we'll have to agree to disagree. BH does the same thing as the polyfill, only more effectively.

leftwinger57

Z3rOs, your last paragraph where your assessing BH-5 is really spot on. Like I already said the stuff works as advertised and one should know what to expect and the amount or size of the panels. I don't even think M5s or Jrs. are worthy of the stuff because of their size. When I did my 2Bs at the right height, length, and spacing and did not enter the passive cavity, it was still so dramatically different I really wasn't sure if it was the thing to do. If used incorrectly or in abundance you will kill the performance of those speakers. I think I might have asked this ages ago but if you have a speaker w/o the poly- fill that's supposed to be there would Corning Pink house insulation work in it's place ?

ZLTFUL

drumminman wrote: »

I suppose we'll have to agree to disagree. BH does the same thing as the polyfill, only more effectively.

How is air passing through the BH5? It isn't, because it is not meant to. The surface of the BH5 is not porous like polyfill. Polyfill is designed to allow air to pass through it to allow for dispersion of the air molecules.
BH5 doesn't pass or disperse the air molecules.

I am not arguing for the sake of argument. I honestly think you are confusing the 2 materials considerably. BH5 is much like and serves very similar purposes to Dynamat in that it dampens/absorbs vibration.
Polyfill does not. Polyfill disperses air molecules as they pass through it.

Polyfill: isothermic reaction which is the change in air density with no change in temperature.

BH5: viscoelastic reaction is the propensity of a material to exhibit both elastic and viscous properties while undergoing deformation.

The science of the materials and what they are doing are very different from each other.

drumminman

One more time and I'm done: "Product: A 5 layer high efficiency acoustical absorption pad with a pressure sensitive adhesive back. Use: to provide the best complete acoustic damping for speaker and subwoofer enclosures."

It absorbs sound waves, not air, in order to prevent them from bouncing around inside the cabinet and hitting the back of the MW's. It may have a secondary function of dampening speaker wall vibrations, but it's primary purpose is absorption.

machone

F1
My dishwasher has a damper that opens and closes the vent to cut down on noise when the vent is not needed. I need to replace mine because it failed and I get noise all the time.

ZLTFUL

drumminman wrote: »

One more time and I'm done: "Product: A 5 layer high efficiency acoustical absorption pad with a pressure sensitive adhesive back. Use: to provide the best complete acoustic damping for speaker and subwoofer enclosures."

It absorbs sound waves, not air, in order to prevent them from bouncing around inside the cabinet and hitting the back of the MW's. It may have a secondary function of dampening speaker wall vibrations, but it's primary purpose is absorption.

I think you're confused. That's exactly what I said.
Polyfill isn't there to dampen anything. It is there to help disperse air molecules which then makes the enclosure appear larger to the drivers.

BH5 is absorption and dampening/damping.

2 different materials doing 2 completely different things.
Your original post said they were doing the same thing but they are most assuredly are not. One is damping/absorption (BH5) the other is dispersion (Polyfill).

But your above quote contradicts what you said here:

drumminman wrote: »

BH also makes the cabinet appear larger to the drivers. It's not really for deadening.

Which is the part that I have said and will continue to say is incorrect.
The quote at the top is spot on. This isn't meant as an insult but when you compare the 2, you flip-flopped from what you originally said to now.

Now, we are on the same page.