# I did a modification to dampen driver from enclosure...



## hearingspecialist (Mar 15, 2010)

I installed 3/8's inch rubber weather strip around baffle opening to seperate driver from touching the enclosure and also around inside of opening in case basket of drivers touched the enclosure as well. Immediate difference and I could tell it needed to be recalibrated using my Yamaha YPAO. I had no idea how much coloration was removed. I also noticed a huge difference in low frequency extension and low freq clarity. I could get more 30hz test tones (louder) and sensitivity below 40hz really improved.

Reference: TMM towers using titanium domes and dual 8's in each enclosure. Big 40" towers tuned to 40hz. Calibration used: YPAO "Natural" which was existing program before small dampening modification.


Thoughts??? I do love these simple and cheap mods that make such a difference...


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## Andre (Feb 15, 2010)

*Re: did a modification to dampen driver from enclosure...*

Interesting, I wouldn't think what you did would have mattered honestly. The hole the driver fits in should be just large enough that the speaker basket won't touch the enclosure (unless the driver is loose and wobbling about). Same for the stripping under the lip, every driver I have ever seen has a cork like material embedded in the mounting ring that will not only keep the basket from resonating the enclosure but provide a air seal. 

BUT, if it worked for you SUPER, keep on tweekin.


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## Moonfly (Aug 1, 2008)

*Re: did a modification to dampen driver from enclosure...*

A lot of drivers use a rubber gasket on the drivers outer mounting ring to remove colouration from the cab. MDF can resonate quite easily, and the same can be said with plate amp hum, if not properly isolated the cab itself can amplify the low and normally unheard hum plate amps can generate.

Its a good solution :T


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## Andre (Feb 15, 2010)

*Re: did a modification to dampen driver from enclosure...*

Yes, I was just saying that Usually its already there attached the the basket when bought, Hense I didn't understand why Adding more gasketing would make a difference. If it wasn't there in the first place then I get it...


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## Moonfly (Aug 1, 2008)

*Re: did a modification to dampen driver from enclosure...*

OP, do you have any pictures of your mod? It would be interesting to see the improvements


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## hearingspecialist (Mar 15, 2010)

*Re: did a modification to dampen driver from enclosure...*

^^no gaskets, which I thought was strange. Well, now there is a super tight and proper install. Sure made a difference even though it was awesome before. Now i'm on this kick to dampen the enclosures as much as possible and brace like there's no tomorrow. I'm sure it will all be "over" engineered, but that's how we roll correct??? One day when I can source the proper stuff, is to clay the insides with non drying clay. The towers have med to high pollyfill stuffing currently and it would take a bunch of clay.


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## Moonfly (Aug 1, 2008)

*Re: did a modification to dampen driver from enclosure...*

Gaskets are a must, as is over engineering IMHO. They clay is not something Ive heard of before tough, that sounds expensive and a of a lot of work.


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## Andre (Feb 15, 2010)

*Re: did a modification to dampen driver from enclosure...*

Ooo that clay would be nasty, If you're wanting to dampen the cabinet further (which I suspect the clay is for) try lining it with Dynamat (do both side is asthetics are unimportant..)

As for Bracing and polyfill do things to the volume of the cabinet. Make sure you get the spec on your drivers and get a box sizing program to make sure you stay within the driver(s) sweet spot.


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## Moonfly (Aug 1, 2008)

*Re: did a modification to dampen driver from enclosure...*

Its also common practise to separate the cab into individual compartments for each driver. This not only optimises sections for particular drivers, but stiffens the cab too.


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## bambino (Feb 21, 2010)

*Re: did a modification to dampen driver from enclosure...*

Clay is something used often by competitive car audio guys, i guess it does the trick.:T


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## hearingspecialist (Mar 15, 2010)

*Re: did a modification to dampen driver from enclosure...*

Bingo^ My big claim to fame was 1996 USAC 7th place World Finals finish. But, my sound quality score was one of the shows best. Pro 1-100 watt class. 
reference/proof: http://www.soundoff.org/finales_results/viewable/1996.htm

Enlarge the results and look at Pro 1-100 watt class. We did use clay a bunch in building world competition level cars. I was using Morel drivers made for home use, the clay really does a great job on the sound control aspect of the rear wave. Boy have I graduated since those graduate school days when I thought I knew it all... Now, the smarter I get the dumber I get...


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## bambino (Feb 21, 2010)

*Re: did a modification to dampen driver from enclosure...*

:rofl: I feel the same way i think it's called age and more responsibility:rolleyesno:. I won my first SPL contest by more then 30 db's not a sanctiond event but what a good feeling it was.:sn:


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## Moonfly (Aug 1, 2008)

*Re: did a modification to dampen driver from enclosure...*



hearingspecialist said:


> Bingo^ My big claim to fame was 1996 USAC 7th place World Finals finish. But, my sound quality score was one of the shows best. Pro 1-100 watt class.
> reference/proof: http://www.soundoff.org/finales_results/viewable/1996.htm
> 
> Enlarge the results and look at Pro 1-100 watt class. We did use clay a bunch in building world competition level cars. I was using Morel drivers made for home use, the clay really does a great job on the sound control aspect of the rear wave. Boy have I graduated since those graduate school days when I thought I knew it all... Now, the smarter I get the dumber I get...


I guess clay makes sense in a highly resonant vehicle with panels all trying to ruin your sound, but is it really needed in the home :dontknow:

Anyway, what about those Morel drivers. I was looking at some recently, and they seem at the more expensive end of their particular class. Are they worth the premium?


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## Andre (Feb 15, 2010)

I will have to agree with Moonfly, I can see the clay perhaps working a tad better then dynamat on steel. However in a wooden sub box with vertical surfaces I can see adhearance problems. I have built what I would consider a very dead subwoofer encloser for my truck using 3/4 HDF rather then MDF and wrapped the outside with a double layer of IceShield (poor mans Dynamat).


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## hearingspecialist (Mar 15, 2010)

I love Morel drivers, all sizes and shapes they offer. The sound quality is amazing and accurate. I think clay would be something over engineered in mdf enclosures but, would be cool to measure frequency response and efficiency before and after with all things the same. Can we ever remove too much vibration in an enclosure? All the high end 50K speakers are crazy damped.


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## Moonfly (Aug 1, 2008)

I was recently looking at Morel drivers in relation to building a copy of the sub2. At face value, the Morel seemed to offer a little less performance for a fair chunk more cash (think 50% more). Based on specs alone I couldnt see why ad figured it must simply be down to SQ. Its a pretty expensive experiment in that case though.


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## Andre (Feb 15, 2010)

Wello Doc, I don't really know what the speaker your playing with looks like. If its a ported speaker you really don't want to put any material on the inside as the resonance within the cabinet are what powers the port, adding material with different accoustical properties will making finding the corrrect port size/lenght "difficult". 

On the other hand if it is a sealed box then you do want to dampen internal reasonace (standing waves). As I understand it different materials absord different frequencies and you want your cabinets internal resonace to be above the free air resonance of your driver. I am sure there are programs available to calculate this.

For cabinet resonance I beleive "there is an ap for that" called Vibration. It turns your IPhone, IPod Touch into a spectrum analyzer using the internal accelerometer. I guess this should be able to tell you how dead your box is, however you would have to play with it.


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## bambino (Feb 21, 2010)

Andre said:


> Wello Doc, I don't really know what the speaker your playing with looks like. If its a ported speaker you really don't want to put any material on the inside as the resonance within the cabinet are what powers the port, adding material with different accoustical properties will making finding the corrrect port size/lenght "difficult".


Why then do we so heavily brace our ported boxes i thought the sub is what powerd the port:huh:. As for adding material to the inside of a cabinet, that is where math would come into play to figure out the displacment of what ever your adding.:T


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## Andre (Feb 15, 2010)

Braceing the cabinet decreases the "cabinet's" resonance. Adding Dacron, foam, fiberglass to the inside of the cabinet addresses "internal" resonances (standing waves) like accoustical treatments address resonances in a room. The only reason (besides internal resonance) that I know off to add "fill" to a sealed box is to make the driver act as if its an a bigger box.

Its not the sub that powers the port but the air it moves.


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## JoeESP9 (Jun 29, 2009)

I have found that Mortite works better than clay, doesn't dry out and is easily removable if desired. It can be applied to the cabinet walls or to speakers that have a stamped metal basket. It's applied to the basket only. It can also be used as a gasket. 

I treated a pair of EPI 100's my brother and I gave my mother for Christmas a while back. I coated the woofer baskets, the entire outside of the back panel and the inside of the front panel. While I had them open I also installed two internal braces. One from the front panel to the back panel and one between the sides. I also stuffed the boxes with Acoustistuf.

These are acoustic suspension speakers. The addition of the Mortite and the braces didn't change the internal volume very much and the improvement in the sound was worth it.

They sound much better after my mods.

edit:
Mortite is much cheaper than Dynamat.


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## bambino (Feb 21, 2010)

Where do you find Mortite and where can it be had, sounds interesting.:T


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## JoeESP9 (Jun 29, 2009)

It works well for deadening anything. I originally used it on stamped metal speaker baskets. It worked so well I then tried it on speaker cabinets. It was so effective there I replaced some metal dome tweeters because their ringing became very easy to hear. Since then I've used it to line the inside of a CD case, under TT platters (it completely stops ringing) and TT plinths.

It took less than 4 boxes to do both EPI100's. I used the excess as extra weather stripping on some windows.

I first found it a local True Value hardware store. Home Depot has it. See below, from Home Depot's web site.










$5.67 a box. 


Mortite is the original name in do-it-yourself caulking; and it's still famous for quality & versatility. Mortite Weatherstrip and Caulking Cord will seal windows effectively. But it's also widely used as a gasketing material, sound deadener, insect barrier, crack filler and all around plugger-upper.


Rope caulk
Special project
Use to fill cracks around windows or doors
Fills up to 1/4 in. gap
MFG Brand Name : Thermwell Products Co. Inc.
MFG Model # : B2


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## bambino (Feb 21, 2010)

Thanks Joe, now that i see what it is i guess idid know what it was just not what it is called. Thanks again.:T


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## hearingspecialist (Mar 15, 2010)

I'm gonna have to check that stuff out. Thanks for sharing. Got to love that HomeDepot for having stuff for our addiction I mean speakers...


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