sound proofing

[funbobby]

thinking of putting some insulation behind the door cards any some in the boot to help the speakers, any thoughts or recommendations?

[Mr Heathen]

Ahhh, to help the speakers. You didn't say that in the other thread now did you...

Dynamat to deaden sound & stop rattles. Dynasorb to absorb, diffuse & attenuate speaker back-wave.

[Johno]

Isn't one fo the drawbacks to Dynamat that it's quite heavy compared to other materials avaiable. Is this a myth or a consequence of it's ability to perform, you can't have one without the other etc . .

[Mr Heathen]

Johno said:

Isn't one fo the drawbacks to Dynamat that it's quite heavy compared to other materials avaiable. Is this a myth or a consequence of it's ability to perform, you can't have one without the other etc . .

By 'other materials' are you referring to dedicated sound deadening products, or stuff like flash banding etc?

Compared to substitutes (flash band/expanding foam) it way out performs them weight vs performance wise. Compared to dedicated deadening materials, there is less disparity. It's also expensive compared to some of the others.

All damper/insulator performance is measured by ability to dampen vibration. The unit is called Acoustic Loss Factor (ALF) which is the same as Damping Loss Factor (DLF). The range extends from 0 to 1, with 1 being the best.

Dynamat is about 0.14
Dynamat Extreme is about 0.4.
Brown Bread is 0.39.
B-Quiet is about 0.20
McMaster is rated at .1 and .13.

Therefore the best two materials are Dynamat Extreme and Brown Bread.

I have also heard good things about E-Dead but have not had any personal experience of said product.

[Robertjp]

if DM extreme and brown bread are considered best technically, which is better value for money? (not heard of brown bread!)

[Mr Heathen]

Brown Bread is cheaper, although I notice that the 2 UK sellers I know of don't have it listed on their sites any more.

If you have to ship it from the US, the postage will probably be horrendous & you can probably find deals on Dynamat Extreme bulk packs in the UK which then makes that cheaper. Depends how much you need...

Beware of eBay or you are liable to end up with repackaged flash band at 3 times the price.

[funbobby]

saw some stuff on ebay called fat max or something, sounded pretty good from the ad, buy it in rolls and cut to size.

[Mr Heathen]

funbobby said:

saw some stuff on ebay called fat max or something, sounded pretty good from the ad, buy it in rolls and cut to size.

Fatmat. You can buy more or less the same from B&Q for a 3rd of the price, it's called flash band.

Dynamat extreme is twice as thick, uses a butyl adhesive instead of bitumen/asphalt, has a much higher heat tolerance & uses a thicker aluminum foil constraining layer.

Edited to add; Apparently there is now Fatmat Extreme which uses butyl instead of bitumen & thicker foil.
It's ALF/DLF rating is about 0.25. Better than the original Fatmat but still not as good as BB/DE.

Edited by Mr Heathen on Thursday 18th March 18:00

[mb450]

Have you thought about something like spectrum sludge from second skin? Not sure if it's any good but happened across it a while ago

[morebeanz]

Would I be right in thinking that the biggest problem in a TVR is likely to be sound absorption rather than panel damping?

[Robertjp]

ok this may sounds like a daft question, but having not used the stuff before i dont know the answer. The only real place to install decent sized speakers in a tuscan easily is to use the area under the rear screen with a custom board on which to mount the speakers, which forms a cavity behind the board, that i see would be best filled with dynamat. However, there is carpet glued everywhere there and i would like to cut, damage or remove any of it particularly.

Can you out this dynamat over the carpet or will the glue simply create a mess that will never come off again?

[Mr Heathen]

morebeanz said:

Would I be right in thinking that the biggest problem in a TVR is likely to be sound absorption rather than panel damping?

That would depend on what sort of results you are looking for, whether you want to bock out road noise, or increase the SPL of an audio system inside the car. Most of the stuff will do both to a certain extent, some better than others. There are mass loaded vinyl barriers & vinyl/nitrile closed cell foam products made specifically for sound absorption which are designed to be floated over any dampening materials used.

Controlling panel resonance is an essential step in preventing the transmission of noise. So, if there is any residual resonance after treating with deadening products, using CCF/MLV as a cushion will stop the resonance from exiting the barrier material. They also create a more complex path for the sound to travel through, which furrther increases the effectiveness of the barrier.

The biggest problem in a TVR is that they are inherently noisy cars. To truly, effectively block out engine, exhaust & road noise you would really need to strip the whole interior of the car, seats, carpets, dash, roof lining, door cards etc. dampen 25-40% of the area with your Brown Bread/Dynamat/whatever, then cover the whole of the rest of the area with CCF/MLV & fill everywhere else with expanding foam. Anywhere you leave gaps, you get noise leakage. As a compromise, you can cover the firewall to the front edge of the front seats, doors and rear wheel wells and still get reasonable results.

Robertjp said:

ok this may sounds like a daft question, but having not used the stuff before i dont know the answer. The only real place to install decent sized speakers in a tuscan easily is to use the area under the rear screen with a custom board on which to mount the speakers, which forms a cavity behind the board, that i see would be best filled with dynamat. However, there is carpet glued everywhere there and i would like to cut, damage or remove any of it particularly.

Can you out this dynamat over the carpet or will the glue simply create a mess that will never come off again?

No such thing as daft questions... I'm not familiar with the back of a Tuscan interior, I'm guessing the cavity you speak of leads into the boot? Whichever, putting dampening product on top of carpet won't help as it needs to be bonded to the panels it is supposed to be dampening. It will also stick like st to a blanket & completely ruin your carpets. I'm afraid removing the carpets is the only way to go if you want to achieve any noticeable results.

[morebeanz]

Thanks, Mr H, most helpful.

One of the traumas that I was struggling with was the idea of trying to get behind the dash to ensure an adequate firewall coverage. Of course I then concluded that that rather missed the point of buying a TVR!

[Robertjp]

Mr Heathen said:

No such thing as daft questions... I'm not familiar with the back of a Tuscan interior, I'm guessing the cavity you speak of leads into the boot? Whichever, putting dampening product on top of carpet won't help as it needs to be bonded to the panels it is supposed to be dampening. It will also stick like st to a blanket & completely ruin your carpets. I'm afraid removing the carpets is the only way to go if you want to achieve any noticeable results.

Yes thank-you, saved me wasting money! The cavity is under the rear screen, then the rear firewall, then the tank, then the boot. I guess the resultant cavity behind a custom mounting board will be the width of the interior under the screen and about 6 inches deep.

I dont want to be removing carpets so i guess i will have to rely on their damping effect...