# Decoupling speakers when installing



## Datsubishi (Jan 9, 2012)

What are your opinions and why? Do different scenarios require different answers?


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## trumpet (Nov 14, 2010)

Damn, I voted for the wrong one. I use rope caulk to prevent air leaks between the baffle and the door and the speaker and the baffle. I wouldn't expect this to be necessary every time, but it's quick and very easy to do.


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## sqshoestring (Jun 19, 2007)

I just don't go for it. There may be a place it is needed but I've not found it, but don't install a lot of stuff these days either. I much rather bolt it in and deal with the panel/baffle to make it work like a baffle should....if at all possible. I still figure home speakers are bolted to a sheet of cheap wood for a reason, or they would use something else. So I like to put wood in the doors, but not cheap stuff that falls apart. I'm not saying foam and caulk and all that don't work because I use those too, but not to 'float' a speaker only to seal and deaden and reduce vibrations/etc.


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## BuickGN (May 29, 2009)

I use no baffles in my doors. Just the rubber gasket supplied and the layer of damper and the speaker bolted to the door itself.. It's the only way I could get them to fit without modifying the door card. Surprisingly no door vibration issues but the door card gives me hell.


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## Rodek (Aug 19, 2006)

I have a 1978 car so I just bolt solid and go. Even with 100 watts RMS going to each door, I don't have rattle issues so long as I keep the crossover set around 80hz. My drivers won't handle much lower anyway.


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## Datsubishi (Jan 9, 2012)

I have always installed speakers using the supplied foam but don't think that really decouples as much as try's to seal. Even if using a thick weatherstripping foam, once tightened down I don't know how much it would decouple. I'm going to make my baffles and the surrounding panel as dead and sealed as possible, just wondering others experiences.


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## joshchrans (Mar 11, 2012)

I used speaker gasket tape between the driver and the baffle, non hardening modeling clay between the mdf baffle and the door sheet metal, then more modeling clay all around the outside of the base of the baffle. It added a bunch of mass to the panel, and the Daytons sound amazing. I also added some eggshell acoustic foam behind the speaker FWIW. "Seems" to have raised the freq of the cone breakup a bit...

The clay was like $10 at Michaels


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## eviling (Apr 14, 2010)

sqshoestring said:


> I just don't go for it. There may be a place it is needed but I've not found it, but don't install a lot of stuff these days either. I much rather bolt it in and deal with the panel/baffle to make it work like a baffle should....if at all possible. I still figure home speakers are bolted to a sheet of cheap wood for a reason, or they would use something else. So I like to put wood in the doors, but not cheap stuff that falls apart. I'm not saying foam and caulk and all that don't work because I use those too, but not to 'float' a speaker only to seal and deaden and reduce vibrations/etc.


Take apart a high end speaker and see. Any sizable driver comes with its own decoupling I think as far manufacturing is concearned their fine with out. Allot of subs come with some sort of decoupling but I've had personal experience with decoupling where I've literally gotten rid of a traveling noise by decoupling my speakers. 



Personly I'd suggest decoupling anything on metal. I double decouple ky baffles on a freefloat 1/4" layer of foam and than theirs one on the speaker that ones cranked the one to the door is mildly tight with bolts on the back. That's just how I went about it. I have some seriouse 8' s though  I also than of course have my doors deadened 3 layers deadner than foam. 
Sent from my EVO using Tapatalk 2


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## req (Aug 4, 2007)

i use any method i can to help cancel vibrations.

i use wellnuts, basically rubber rivets, i use duct seal as a mass loading and sealing device instead of caulk\deadener, and i use foam as a gasket seal. all of this in conjunction of marine grade plywood and large bolts to the metal door. if i can, extruded aluminum riveted to reinforce the door helps too. also sealing up any holes in the door skin is super effective. a sheet of ABS\aluminum\whatever + deadener usually works like a charm... i hope you never have to replace your window regulator though!


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## eviling (Apr 14, 2010)

req said:


> i use any method i can to help cancel vibrations.
> 
> i use wellnuts, basically rubber rivets, i use duct seal as a mass loading and sealing device instead of caulk\deadener, and i use foam as a gasket seal. all of this in conjunction of marine grade plywood and large bolts to the metal door. if i can, extruded aluminum riveted to reinforce the door helps too. also sealing up any holes in the door skin is super effective. a sheet of ABS\aluminum\whatever + deadener usually works like a charm... i hope you never have to replace your window regulator though!


I have a dying passenger side motor in the window  

Sent from my EVO using Tapatalk 2


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## goodstuff (Jan 9, 2008)

req said:


> i use any method i can to help cancel vibrations.
> 
> i use wellnuts, basically rubber rivets, i use duct seal as a mass loading and sealing device instead of caulk\deadener, and i use foam as a gasket seal. all of this in conjunction of marine grade plywood and large bolts to the metal door. if i can, extruded aluminum riveted to reinforce the door helps too. also sealing up any holes in the door skin is super effective. a sheet of ABS\aluminum\whatever + deadener usually works like a charm... i hope you never have to replace your window regulator though!


I could google but tell us more about the wellnuts req.


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## RNBRAD (Oct 30, 2012)

I think it depends on the speaker. I've had to go back and decouple in only one instance cause of the sound. Didn't realize it made a difference to the speaker, but in some cases, might be rare, but it can. I generally just bolt them up solid, if I have problems with vibration transfer then I will work to elimate that in different coupling/decoupling ways. So yes, different scenario's require different solutions. I'm typical, if I can do it the easy way and get away with it I will.


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## HondAudio (Oct 19, 2006)

I'm using a multi-layer/multi-material approach to my midbass baffles. From the "top" down: 

1. My midbasses (JL C5-650CWs) are mounted to a 1/2" MDF rings, attached with 8-32 machine screws and counter-sunk threaded inserts on the backside. The speakers attach at 8 points; offset are another 8 holes on the "top" side of the ring to countersink more 8/32" machine screws; these go through the following layers:

2. A ~1/16" layer of closed-cell foam

3. A 3/16" layer of cork, with some #8 x 1/4" diameter x 3/16" tall aluminum spacers. The machine screws go through the spacers, which protect the cork from any rubbing on the threads of the screws and prevent any movement of the ring.

4. Another layer of ~1/16" closed-cell foam

5. A "trident" of 1/2" MDF, coated with bedliner like the MDF ring in #1. More threaded inserts are counter-sunk in the "bottom" of this layer, and the machine screws secure the top MDF ring through the CCF, cork, CCF, and finally into this layer.

~~~~~~~~~~

6. Another layer of ~1/16" closed-cell foam in the "trident" shape.

7. Another layer of 3/16" cork in the "trident" shape. The MDF tridents are bolted through these two layers and into the door, with washers on both sides and a Nylock nut inside the door; unlike above, I'm using 10-32 machine screws here.

I have yet to find out how all this is going to sound. It's been a huge battle to get to this point and making sure everything will fit under the door card - as it is, I'm going to have to trim some of the plastic behind the OEM grill.


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## fisc2307 (Oct 29, 2011)

I probably went overboard but instead of MDF I wet this route:
1.Speaker
2.Butyl Rubber
3.1/4" Plastic Cutting Board Baffle
4.Butyl Rubber
5.1/4" Plastic Cutting Board Baffle
6.Butyl Rubber
7.1/4" Plastic Cutting Board Baffle
8.Butyl Rubber
9.Door
The Baffles are bolted to the door and the speakers screwed into the baffles.


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## Bayboy (Dec 29, 2010)

fisc2307 said:


> I probably went overboard but instead of MDF I wet this route:
> 1.Speaker
> 2.Butyl Rubber
> 3.1/4" Plastic Cutting Board Baffle
> ...



Overboard??? Nahhhh...


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## Sine Swept (Sep 3, 2010)

BuickGN - I feel your pain on rattling door cards. I just keep adding duct seal / aluminum foil tape to the back of them and its getting better by the pound. I also added 4 rivnuts to the outside edge of the door and fasten the door card with 10-32 machine screws and dome washers which prevent the screws from biting through the plastic


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Unless the speaker is floating on a layer of foam, or other flexible substrate, its not truly decoupled. If its bolted to something solid, the speaker is still coupled by those bolts. 

Read some more here.

google "linkwitz decoupling"

click on the first link.

Shows accelerometer measurements showing the results of decoupling.


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## Bayboy (Dec 29, 2010)

TOOSTUBBORN2FAIL said:


> Unless the speaker is floating on a layer of foam, or other flexible substrate, its not truly decoupled. If its bolted to something solid, the speaker is still coupled by those bolts.


Exactly. The extraneous efforts to "decouple" is more or less along the lines of adding mass and changing the resonance of the affected panel. The same thing will be attained if the mass was just added in the immediate surrounding area instead of between the baffle & door skin.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Bayboy said:


> Exactly. The extraneous efforts to "decouple" is more or less along the lines of adding mass and changing the resonance of the affected panel. The same thing will be attained if the mass was just added in the immediate surrounding area instead of between the baffle & door skin.


Yep. My last build I coupled direct to the kick panel, with carpet sealing it, and concrete in the kick panels to kill resonance. Next build, I'll experiment with true decoupling and solid coupling.


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## Bayboy (Dec 29, 2010)

Deadening the immediate areas with as much mass as possible is the simple solution, but made more complex by use of drivers not necessarily made for car audio use. IE using larger than normal & low Qts drivers crossed low exacerbates the problem.


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## iScream (Apr 1, 2013)

I know this thread is a little old but wouldn't serious decoupling actually reduce the output of your speakers? If they're mounted so softly that the speaker frame actually moves, that has to be wasted energy. 

I think it would be somewhat like setting off a firearm cartridge outside of a gun chamber. What happens is that the projectile goes one direction, and the case goes the other direction, but neither with very much force.

When you fire a gun, the brass case isn't allowed to move much, so all the pressure is used to force the projectile (bullet) out the barrel.

If the speaker frame is moving in the opposite direction from the cone, that means not as much air is being moved.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

The analogy doesn't cross over, since the brass is usually lighter than the bullet.

Usually, the frame/motor is heavier than the cone/voice coil, sometimes by as much as 100 times or more. So yes, theres a loss in output, but if there basker/motor weighs even just 50 times as much as the cone/voice coil, it would only be a 2% loss in output, which is inaudible.


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## Heterosapian (Dec 31, 2011)

I try to get everything rock solid and sealed with rope caulk and duct seal. If that's decoupling then I guess so, but like someone mentioned earlier, once everything is bolted in place, the driver, baffle and door are basically one unit.


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## Orion525iT (Mar 6, 2011)

I started a thread about this recently, not realizing this thread existed. I would say that decoupling should be done, where it can be done.

There was a paper that somebody linked to in my thread where they did tests to study the effects of decoupling. The thing I took away from the paper was that, even a well constructed enclosure will pick up resonance from the driver if the driver is hard mounted. There was measurable coloration. So I can see how vibrational energy can be transferred through the entire body of the car, even if the immediate area is deadened. There is no way to make the mounting area perfectly dead. But if you decouple the driver, that resolves the issue.

I hard mounted my 8" subs in my kicks. They do have a rubber gasket, but its rather hard rubber, and more importantly, the mounting screws have no such decoupling. The baffle area itself is very dead. I still have reasonance issues, but its the doors that resonate. These are high frequency resonances, not rattles from big bass hits. The interesting thing is that even with the doors wide open, they still resonate. Remember, the drivers are not in the door, they are in the kick panels. The only thing that connects the door to the body are two hinges, yet the vibrational energy is still transfered. It will be interesting to see what happens if I actually decouple the drivers.

But many of us go to great lengths to decouple our car interiors to kill road noise and panel resonance. So no need to decouple the driver, just decouple the car, problem solved! Except I actually think the issue is somewhat the opposite in the case of a running / driving car. We decouple the interior, but there are point areas of the car body that often are not; in fact many times the attempt is to firmly attach things to these point areas of the car body. What point areas? Well its the drivers themselves. If the driver can transfer energy to the car body, then the car body most certainly can transfer energy to the driver.

In any case, it has been reported that the Magic Bus uses generator mounts to attach the sub enclosures. I suspect the builder knows a thing or two about building a solid, dead box. Yet the extra step was taken to decouple the enclosures from the vehicle body. Again, I think this shows that even the best box will pick up or transfer resonances when hard mounted.


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## sqshoestring (Jun 19, 2007)

People have decoupled sub boxes thinking it would solve all their problems, then they found that it was actually the air pressure/waves from the sound that was making everything vibrate lol. When you mount a speaker you are only adding to the mass of the basket/motor. Personally I only saw it as an option when you have a terrible place to mount like a plastic door panel, or in only a few special cases.

Remember dampening and decoupling are two very different things. Damp means to stop vibration usually with more mass and/or absorbing materials. Decouple means to suspend away from so it can vibrate all it wants on its own. If that is actually the case you will lose bass output, and/or get some kind of output from the frame that is vibrating. So typically I see it more as using a flexible material to mount on that absorbs _some _vibration of the speaker frame, usually a well damped material is used. Usually resulting in a change of resonance to something that causes less of a problem. Even so you still have air pressure that will vibrate other surfaces if it can, so decoupling can't easily solve those issues.


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## Orion525iT (Mar 6, 2011)

sqshoestring said:


> Remember dampening and decoupling are two very different things. Damp means to stop vibration usually with more mass and/or absorbing materials. Decouple means to suspend away from so it can vibrate all it wants on its own. If that is actually the case you will lose bass output, and/or get some kind of output from the frame that is vibrating.


No misunderstanding here. The critical aspect of decoupling the driver is to make sure the driver and baffle are decoupled from the enclosure but also that combined they have _sufficient mass to also dampen against cone movement_. Otherwise you will impact the performance of the driver. You can do both if designed properly.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

sqshoestring said:


> People have decoupled sub boxes thinking it would solve all their problems, then they found that it was actually the air pressure/waves from the sound that was making everything vibrate lol. When you mount a speaker you are only adding to the mass of the basket/motor. Personally I only saw it as an option when you have a terrible place to mount like a plastic door panel, or in only a few special cases.
> 
> Remember dampening and decoupling are two very different things. Damp means to stop vibration usually with more mass and/or absorbing materials. Decouple means to suspend away from so it can vibrate all it wants on its own. If that is actually the case you will lose bass output, and/or get some kind of output from the frame that is vibrating. So typically I see it more as using a flexible material to mount on that absorbs _some _vibration of the speaker frame, usually a well damped material is used. Usually resulting in a change of resonance to something that causes less of a problem. Even so you still have air pressure that will vibrate other surfaces if it can, so decoupling can't easily solve those issues.



Google "linkwitz decoupling", and read the second link that pops up. Should be a .doc file, a report by Andy Jones. He took accelerometer measurements from both the cone and magnet. The magnet actually behaved best when completely decoupled, hanging free air from bungee cords. It behaved best in both frequency response, and time behavior. There was a loss of cone movement on the bungee cords, but it was only 1%, so completely inaudible. Also tested was cabinet vibration, and it was shown that the decoupled driver reduced cabinet vibration by more than 20db, and after an impulse, the cabinet stopped vibrating much more quickly.


The important thing to remember is that the magnet is the "ground reference" for cone motion. So anything you do to improve the magnet response, will improve everything else. And clearly the magnet behaves better when the mounting point on the frame is decoupled. 

Another thing to note, is that aside from the magic bus, and highly's 18" spare tire IB build, I've never seen another build on this forum or any other audio forum with a true decoupled installation. Every attempt I've seen aside from those two, still couple the speaker to the hard surface with screws.


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## MADXF (Jun 30, 2010)

Isn't the cone decoupled by a spider and a rubber surround?

Bolting the speaker in hard seems to me like a good way to add stiffness to the metalwork around it.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Yes, but the magnet is the reference point to which the cone moves. If the magnet behaves funny, so does the cone. This is what the .doc file I suggested googling studies. It shows that when hard clamped, the magnet behaves much worse in both time domain and frequency response when the speaker is bolted to a hard surface, than when the speaker is effectively decoupled from the hard surface. Listening tests implied that it was audible, and preference was for the decoupled speakers. Keep in mind, this is mainly effective in the bass frequencies.


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## Datsubishi (Jan 9, 2012)

I found this image on the Eclipse Japanese sight. It's what sparked my interest in this topic besides it being a common practice to decouple, and many manufacturers including the foam to do so with their speaker sets. 










This was on a high end speaker set that came pre-installed in pods. You can see that the speaker basket is completely decoupled from the enclosure itself. By the looks of it anyway. I don't read Japanese.


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## req (Aug 4, 2007)

well nuts


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

^those with something to seal the speaker (foam, rubber of the same hardness, etc) would be perfect.


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## strohw (Jan 27, 2016)

Polled threads must get bumped when someone fills out the poll?


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## Babs (Jul 6, 2007)

req said:


> well nuts



That's a great idea. Basically rubber rivnuts. I have a marson rivnut tool. I should get some these on hand. Wonder if they'd be strong enough for the IB wall for the top attach points across the lip down at the rear deck metal? I'll possibly run a row of them to attach to as well as the sides.


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## goodstuff (Jan 9, 2008)

Babs said:


> That's a great idea. Basically rubber rivnuts. I have a marson rivnut tool. I should get some these on hand. Wonder if they'd be strong enough for the IB wall for the top attach points across the lip down at the rear deck metal? I'll possibly run a row of them to attach to as well as the sides.


Wow thats awesome.


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## ErinH (Feb 14, 2007)

Babs said:


> That's a great idea. Basically rubber rivnuts. I have a marson rivnut tool. I should get some these on hand. Wonder if they'd be strong enough for the IB wall for the top attach points across the lip down at the rear deck metal? I'll possibly run a row of them to attach to as well as the sides.


the only flip side is at some point, where the baffle would be 'decoupled', you will lose output. 

there's a tradeoff here between achieving the output you desire and remedying vibration in the car itself.


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## Sine Swept (Sep 3, 2010)

Why not deaden the motor while you're in there.

I can recall someone once asking me if I had some Dynamat they could use on a set of headphones.


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## gstokes (Apr 20, 2014)

I use a foam baffle to decouple the speaker from the door skin, done deal..

The bottom of the baffle is cut out so the woofer can breathe to the door, think "infinite baffle"..


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

gstokes said:


> I use a foam baffle to decouple the speaker from the door skin, done deal..
> 
> The bottom of the baffle is cut out so the woofer can breathe to the door, think "infinite baffle"..


That isn't truly decoupling the speaker, that is just sealing it to the door, as the screws still couple it to the door. Check Erinh's build log when he installed the 10's in his kicks for an example of decoupled installation.


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## gstokes (Apr 20, 2014)

TOOSTUBBORN2FAIL said:


> That isn't truly decoupling the speaker, that is just sealing it to the door, as the screws still couple it to the door. Check Erinh's build log when he installed the 10's in his kicks for an example of decoupled installation.


hmm, i see your point..


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

It's actually really difficult to do and have it be secure. Erin used mounted the speaker to a baffle, the is only attached to the enclosure with butyl rope.


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## caraudiopimps (May 4, 2016)

trumpet said:


> Damn, I voted for the wrong one. I use rope caulk to prevent air leaks between the baffle and the door and the speaker and the baffle. I wouldn't expect this to be necessary every time, but it's quick and very easy to do.


I do this too, or use speaker gasketing tape


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