[Ragul]

Is dynamat good for lining the inside of DIY speakers or only good sandwiched between two panels? Is it good for damping resonances only or also cutting down on sound reflections and standing waves? Or should I go for glass wool lining instead? And is glass wool useful when stuck to inside panel or does it require an air gap between panel and itself to be effective?

where can I buy just 1 sq mtr of dynamat in Bangalore or do I need to buy a whole roll? Whats the price per sq. mtr?

Thanks for some quick advice.

--R

[DerAlte]

Originally Posted by Ragul

Is dynamat good for lining the inside of DIY speakers or only good sandwiched between two panels? ...

* Dynamat and similar damping sheets work best damping surface vibrations

* It works best on plain large surfaces, applied on one side

* If sandwitched, it will damp one surface only. Difficult to visualize how one can sandwich it, considering one surface has adhesive. For sandwiching, closed cell foam or non-woven felt carpet works best. Or, if the surfaces are far apart more than 0.5", stuffing cc foam / cotton waste works better

* It will not cut down on reflections and resonance (standing waves) in cabinet. For that one has to use either glass wool or synthetic wool (used in cushions and pillows). It doesn't have to be glued / stuck to the surface, but doing it keeps it organized and less messy. Putting it in a cloth cover and placing the resultant 'pillow' would be doing the same

* Dynamat comes as sheets, not rolls IIRC

[Ragul]

Originally Posted by DerAlte

* Dynamat and similar damping sheets work best damping surface vibrations

* It works best on plain large surfaces, applied on one side

* If sandwitched, it will damp one surface only. Difficult to visualize how one can sandwich it, considering one surface has adhesive. For sandwiching, closed cell foam or non-woven felt carpet works best. Or, if the surfaces are far apart more than 0.5", stuffing cc foam / cotton waste works better

* It will not cut down on reflections and resonance (standing waves) in cabinet. For that one has to use either glass wool or synthetic wool (used in cushions and pillows). It doesn't have to be glued / stuck to the surface, but doing it keeps it organized and less messy. Putting it in a cloth cover and placing the resultant 'pillow' would be doing the same

* Dynamat comes as sheets, not rolls IIRC

I was thinking of applying glue to the other side and sealing two 12mm hdf ply together. But I think I'll just go for a 30mm door panel HDF instead.

So now I'll try pasting dynamat on the inside to damp the resonance of the block board material with its random internal millimeter gaps and then stick glass wool on top for a uniform performance all around inside to contain reflections.

What is a typical sheet size?

Thanks
--R

[DerAlte]

Originally Posted by Ragul

... 30mm door panel HDF instead. ...

I used to do it with materials with higher density & more material uniformity:
* Teak, rosewood and such high density wood. At a pinch even Sal, Matti and Honne will do if I have to do it now, since >=1" teak / rosewood planks rare and very expensive now
* HD Particle board, the one that comes with laminate on either side now. Used to come without laminate earlier
* MDF used in cabinetry - not very dense, but at least very uniform without any included faults or airgaps
* Sandwiching a fiberglass sheet (the ones used for gate shielding and roofing), with 2 sheets of treated 1/2" Marine Ply. Easy to bond with bulk Araldite, and then to cut and join. Comes out extremely stiff, and sort of self-damping (the FG sheet)
With these, at a pinch I need not use damping material. Just some recron (synthetic wool) damping for cutting out standing waves

Treated blockboard like used for door shutters (I understood you meant that) would be lowest on my list because wood and glue quality is suspect, and density is too less, much less than MDF.

Originally Posted by Ragul

... What is a typical sheet size? ...

Usually 18"x32" or 24"x48", depending on pack. Some brands go upto 4' x 4'.

Check the DampMat thread in this section. Bhpian monty9991 manufactures damping sheets. 4sft sheets sized 16"x36", 9 sheets to a pack. PM him.

[Invader]

Can anybody confirm if I can safely use dynamat (dynaliner 1/4 inch) sheets in the car (Punto) ceiling (inside) and still install the OEM roof panel back without any modifications?

[Pedaltothefloor]

What can I use on the firewall to reduce engine noise inside the cabin?

[Guite]

Originally Posted by Pedaltothefloor

What can I use on the firewall to reduce engine noise inside the cabin?

I suppose a hood liner would work best here for the fact that it is designed to withstand engine heat. Having said that, I wonder how people install it on the engine bay side because there are so many obstruction. On the cabin side it requires removal of entire dash board, which only authorised service centres can do, afaik. If you get any damping done on firewall, please let us know the details.

[roadrage]

Originally Posted by great_guns

I came across a couple of products on eBay called TufClad.
Anyone ever used these?

http://www.ebay.in/itm/TufClad-Sound...ht_2287wt_1139

http://www.ebay.in/itm/TufClad-Stand...ht_2047wt_1139

I came across the same. I May have not searched thoroughly but i couldnt find anyone having thrown light on the above product. Kindly explain.

[navin]

Originally Posted by Ragul

... now I'll try pasting dynamat on the inside to damp the resonance of the block board material with its random internal millimeter gaps and then stick glass wool on top for a uniform performance all around inside to contain reflections.

Please be aware that all woods except well seasoned hard woods (aged Burma teak for example) have limited life in a car.

Also hard woods sing. This is good and bad. Good if you are making a guitar or violin which is producing music but not so good if you are making a speaker which is RE-producing music.

Damping materials must be by nature be non-resonant and moderately dense. If being used as a sandwich it's density should be as different as that of the other materials as possible (for example a foam and wood sandwich). Rubberised sheets like Dynamat have been found to extremely good with car panels.

[Ragul]

Originally Posted by navin

Please be aware that all woods except well seasoned hard woods (aged Burma teak for example) have limited life in a car.

Also hard woods sing. This is good and bad. Good if you are making a guitar or violin which is producing music but not so good if you are making a speaker which is RE-producing music.

Damping materials must be by nature be non-resonant and moderately dense. If being used as a sandwich it's density should be as different as that of the other materials as possible (for example a foam and wood sandwich). Rubberised sheets like Dynamat have been found to extremely good with car panels.

Thanks. This is for home speakers only. Any idea how one can get a hardwood cabinet to sing around 6kHz only? Ok asking for too much... I guess not.

[navin]

Originally Posted by Ragul

Thanks. This is for home speakers only. Any idea how one can get a hardwood cabinet to sing around 6kHz only? Ok asking for too much... I guess not.

Best person to ask is Lou at Daedalus Audio. He makes speakers using solid wood instead of ply.

To reduce resonance I use a sandwich of wood, resin bonded fiberglass and lead sheet as shown in the photo attached.

[schakravarthy]

I own a 2009 Punto Diesel. I was fairly happy with the Stock sound proofing in my car, ie., until I sat myself in a 2013 Punto. The sound insulation in the new car is unbelievable! My car feels like a tractor in comparison!!

I now plan to go the DIY way to boost up the sound proofing level in my car.

I've identified the 5 doors, spare wheel well and firewall as potential areas to sound proof. I won't tamper with the wheel arches, roof, floor ( I have the rubber matting on the floor, so don't want to tear it apart ) unless it is absolutely necessary. Also, I don't want to go the Dynamat or other off the shelf product way.

I plan to use neoprene rubber pieces as mass dampers (on the bare metal surface), followed by a closed cell foam layer (the dark grey coloured one commonly used in packaging) as absorber and finally another layer of neoprene sheet as a barrier.

Am I heading in the right way? My logic says that 2 rubber layers enclosing a foam layer in between is correct as it'll keep the outside noise away, at the same time retain the 'inside' sound.

[DerAlte]

Originally Posted by schakravarthy

...I now plan to go the DIY way to boost up the sound proofing level in my car.

... I don't want to go the Dynamat or other off the shelf product way. ... My logic says ...

Why did you decide to stay away from commercial / conventional damping materials - cost or technical considerations? Your logic could either be untested, or tested and discarded by others.

The technique you have described is fine for open access, for example the spare wheel well. For the doors (limited access) have you considered the difficulty in applying? Most people tend to use KISS principle as it saves them effort and money ultimately.

[schakravarthy]

Originally Posted by DerAlte

Why did you decide to stay away from commercial / conventional damping materials - cost or technical considerations? Your logic could either be untested, or tested and discarded by others.

The technique you have described is fine for open access, for example the spare wheel well. For the doors (limited access) have you considered the difficulty in applying? Most people tend to use KISS principle as it saves them effort and money ultimately.

Commercially available sound dampeners are a bit like jack of all trades. From what I have gathered, these might need additional foam reinforcements to achieve good results.
I'm trying to emulate the layers found in the commercial dampeners, but with alternative materials.
I didn't understand what you meant by "limited access". Could you please elaborate a bit? I plan to pry open the plastic panel and apply the layers.
That apart, should it be rubber-foam, or rubber-foam-rubber?

[anujmishra]

Originally Posted by condor

Coming back to tackling rattling of door-pads: Forget the Yoga mats. You can do it at just 15-20% of the cost of yoga mats.
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Width of sheet: about 50 inches.
Attachment 915738
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condor, I seriously want to apply this in my Safari in coming days to reduce door vibration. Also, my requirement is to improve the sound quality as well inside cabin from my music system. My requirement as per priority are

1. Reduce the outer noise/vibration and make cabin as silent as possible in Safari.
2. Increase the quality of sound.

For this, shall I go for damping with available products (like DampMat etc.) or above solution will do?