# Adding sound deadener to waveguide bodies



## bigbubba (Mar 23, 2011)

I've seen a picture somewhere that a guy added sound deadener to the waveguide body and was wondering if you can gain anything from this? I have not heard or seen anybody else do this except for that one picture. I have a set of the early full body waveguides that were made out of fiberglass and seem pretty thin compared to the newer/thicker plastic bodies. Would resonance play a part in the sound from the thinner waveguide material?

....Or does it not matter one way or the other?


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## Horsemanwill (Jun 1, 2008)

tha's basically why it's done.


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## bigbubba (Mar 23, 2011)

So, you have done this to yours?


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## Horsemanwill (Jun 1, 2008)

no but i've seen it done many times


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## minbari (Mar 3, 2011)

as long as it is the outside of the body. dont want to mess with the throat.


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## bigbubba (Mar 23, 2011)

I was thinking that it couldn't do aything but help with resonance but I haven't seen or heard of anyone doing this with the exception of that one picture that I can't find. That being said, I have by no means seen every horn install either. Just wanted to know if it helps, how much of a difference does it make before and after you do it. Can you hear the difference?

I'm not going to modify the inside of the horn. I will have to modify the mounting locations slightly to make sure my new drivers are centered over the opening to the throat, not creating a lip with the adapter.


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## thehatedguy (May 4, 2007)

It makes a rather large difference on the big horns like the USD and big body IDs...not much on the ID mini horns. It can make a big difference on the Veritas bodies, but I found another way to prtty much make that horn stop ringing.


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## fish (Jun 30, 2007)

thehatedguy said:


> It makes a rather large difference on the big horns like the USD and big body IDs...not much on the ID mini horns. It can make a big difference on the Veritas bodies, but I found another way to prtty much make that horn stop ringing.



Care to share what that remedy was?


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## subwoofery (Nov 9, 2008)

fish said:


> Care to share what that remedy was?


By throwing it in the bin  

Kelvin


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## bigbubba (Mar 23, 2011)

Thanks for the input. At least now I don't feel like I would be wasting my time by doing this. Now I just need to make mounting tabs and deaden.

Thanks


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## thehatedguy (May 4, 2007)

With the Veritas, I found that if you added some pressure to the mouth of the horn it would stop it from ringing. It doesn't take a lot of pressure to do this. You could clamp the mouth, but that isn't practical to do. So what I did was drill a hole al the way through the mouth in the middle where the Vertias flatten or squish in as far towards the edge as I could get. Then I put a machine screw in the hole that could reach all the way through the mouth. Inside the flat spots I put two nuts- one on top and one on bottom. I put the screw through those, threaded through the nuts and out the other side. Then I tightened the nuts (it would loosen one since it is going the opposite way)...but it ended up pushing the mouth of the horn open so so slightly putting pressure on it. You would need a micrometer to measure how much it opened the mouth up...you could see a difference.

But once the mouth was put under some pressure, the ringing was audibly cut down a great deal once put under some stress.

I guess you could do this with the fliberglass and plastic horns too, but I would be too worried about deforming the shape of the mouth too much...the thick aluminum just didn't physically move as much.

I also port matched the adapters to the horns since there was a pretty big difference between the two...or maybe it was the horns to the adapters, whichever one was the smaller of the two (I don't remember off of the top of my head since that was 6-7 years a go).


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## thehatedguy (May 4, 2007)

One could also put a vain down the throat like the Illusion horns and the big Altec 511s and 811s.

At one point I was going to make a straight adapter for the Veritas but never did.


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## SSSnake (Mar 8, 2007)

The PE adapters matched the throat opening on the old ID fiberglass horns very well. I did deaden those but didn't notice much difference when installed. On the bench the mouth would ring a little but with my mounting scheme the mouth was pressed very firmly against some closed cell foam I added to the bottom of the dash (the closed cell foam was trimmed back just enough so as not to create a gap between the end of the mouth flare and the dash). IMO that is what kept the mouth from ringing once installed. Prior to deadening/adding the foam they imaged at the mouth rather than the throat.


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## bigbubba (Mar 23, 2011)

I also got the PE adapter and it lined up with the opening but the horn had a slight lip right before the transition that needed to be sanded down. I'm going to have to get a little creative with installing the passenger side horn. The way the glove box door comes down is hinged weird and comes back past the edge forcing me to mount it further back from the edge than the driver side.

I also considered adding a support through the middle of the front edge of the horn body and fiberglass it on both sides to reduce any flex but didn't know if it would help or hurt the sound.

If I add another layer or two of fiberglass around the outside of the horn to help make it more rigid would that deform the body once it cured? I don't normally work with fiber glass so I don't know if there is a shrinkage factor when it cures.


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## thehatedguy (May 4, 2007)

What, which horns do you have? Fiberglass doesn't like to stick to the urethane horns that well. I mean it will, but the urethane has oils in it from casting that could inhibit adhesion if not taken care of.

Don't worry about deformation of the horn.


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## bigbubba (Mar 23, 2011)

I have the fiberglass full bodies. The platform the compression driver mounts to looks to be made of particle board and glassed over it.


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## SSSnake (Mar 8, 2007)

Yep that sounds like the old ID full bodies.


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## SSSnake (Mar 8, 2007)

IMO and there are definitely those on here who are more knowledgable, getting the horn to underdash transition right is critical. If this is done correctly I don't think it would be possible for the top of the mouth to ring. That leaves really only the potential for the bottom to ring. If you have the space, a round over made out of MDF attached to the bottom of the horn would deaden the mouth and lower diffraction. If not then just add a little deadener and roll on. The advantage to adding a round over other than diffraction is that it will allow you a very clean area to attach foam to the under body of the horn and kill reflections from the upper range of the midbass.


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## bigbubba (Mar 23, 2011)

Once I get the horns mounted I will be making another cover to replace the stock one. Not sure what it will be made out of yet but it will have foam attached to it to absorb flections from the midbass in the doors. 

On the foam, are you supposed to use OCF or CCF to cut down on reflections? And what kind of material can you cover it with to allow it to still do its job, carpet?

Again, thanks for all the comments. It's greatly appreciated.


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## thehatedguy (May 4, 2007)

If you have the older fiberglass horns, I would add a few more layers to it. Might could put a layer of your favorite damping mat down first, glass a few layers of heavy cloth on it, and then another layer of damping mat on top of that.

The foam you want to use inside the horn is a 30 pore per inch (ppi) retictulated filter foam. Some people find this kind of foam in the pet store as fish tank filter foam...I haven't seen it, but I don't do too much shopping for fish stuff. I bought a sheet of the foam from Welcome to Foam Factory, Inc. It's listed conviently under speaker/filter foam. Other places have it. Main thing is you want to find a piece thick enough so that you don't have to glue the pieces together...so try to get 1" thick pieces and cut it to fit inside the horn without squishing it too much.


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## bigbubba (Mar 23, 2011)

Sorry for asking what might be a stupid question but why would you put foam IN the horn? What results does that give? Do you fill the entire body or half or....


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## SSSnake (Mar 8, 2007)

OCF is what you want for the underside of the horn. Jason is referring to stuffing the horn to cut down on HOMs. Check out the DIYaudio site for extensive discussion. The proponent of the foam is Earl Geddes and one smart cookie. However Earl has waffled as to whether reticulated or OCF is used. My opinion is try the horn both stuffed and un-stuffed and decide what you like. 

Jason, why the recommendation of extra fiberglass on the old full bodies. Mine were THICK and didn't seem to have any issues except as noted earlier.


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## bigbubba (Mar 23, 2011)

SSSnake said:


> OCF is what you want for the underside of the horn. Jason is referring to stuffing the horn to cut down on HOMs. Check out the DIYaudio site for extensive discussion. The proponent of the foam is Earl Geddes and one smart cookie. However Earl has waffled as to whether reticulated or OCF is used. My opinion is try the horn both stuffed and un-stuffed and decide what you like.
> 
> Jason, why the recommendation of extra fiberglass on the old full bodies. Mine were THICK and didn't seem to have any issues except as noted earlier.


Ah...gotcha. As far as the thickness of the horns, mine seem very thin, 1/8' at best. If you were to squeeze on the opening of the horn with your fingers it will give quite a bit. I'd be afraid to do it too hard fearing it would crack. I'll take a couple pictures of them when I get home today and post them. I ordered these CD1E's when they were first available for sale BITD.


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## subwoofery (Nov 9, 2008)

bigbubba said:


> Sorry for asking what might be a stupid question but why would you put foam IN the horn? What results does that give? Do you fill the entire body or half or....


The HOMster! (or How I Learned How to Fix a Horn) - diyAudio 

Kelvin


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## bigbubba (Mar 23, 2011)

subwoofery said:


> The HOMster! (or How I Learned How to Fix a Horn) - diyAudio
> 
> Kelvin


That is one interesting read. Thanks guys.


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## bigbubba (Mar 23, 2011)

I have got to stop getting on this site at work. I lost 2 1/2 hrs of work today.

Here are a few pics of the ID waveguides I am looking to install with the exception of the drivers, I got new ones.


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## Eric Stevens (Dec 29, 2007)

Cover them completely with any high quality sound damping material. Multiple layers wont hurt either. You want them dead and non-resonant.

Eric


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## bigbubba (Mar 23, 2011)

Eric Stevens said:


> Cover them completely with any high quality sound damping material. Multiple layers wont hurt either. You want them dead and non-resonant.
> 
> Eric


Dead...got it! Thanks!


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## SSSnake (Mar 8, 2007)

The man has spoken.


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