slat resonator/drt wall finish.....

[Md.poneer]

salam ,
i have 9.5' mahogany slot resonator at both front side walls.......the people that i gave contract to varnish and paint ,suggest me to varnish with mat finish not glossy for acoustic reasons.but i have seen many studios over the forum their slot finish is very glossy and attractive.......... i need to know ....
how glossy i can make it for both CR and LR?
what type of paint should i use on dry wall?......plastic and duco paint is very available here...

[Soundman2020]

It makes no difference at all! Make it as shiny or as matte as you want. Sound waves don't care what color it is, or how shiny or dull the surface is. Even the very highest frequency sound waves have wavelengths that are much, much longer than the surface irregularities that make paint "matte" or "gloss". So use whatever you think looks good. Paint is one area of studio building where there are practically no acoustical benefits. (Probably the ONLY part where it doesn't matter, acoustically!)

[BriHar]

Hi Stuart,
You mean you're not familiar with soundproofing paint?
http://industrialcoatingsworld.com/news ... at-silence
Check out the discussion over this on GS

[Soundman2020]

Oh yeah, I've seen that stuff! It's not the only paint out there that makes grandiose claims...

I also heard that if you squeeze snakes hard enough, then you can get oil out of them, and that oil can also be used as acoustic paint...

It's amazing how that web site talks all about how their product was tested in various places, and even gives you links the test data... Except that the links do NOT actually take you to the data! They just take you to the home page of the organization that allegedly did the testing.. The actual test data seems to be pretty hard to find. I wonder why?

- Stuart -

[Soundman2020]

Say!!!! I found the actual test data!

http://www.vertetek.com/public/pdf/Test%20Data.pdf

According to the tests they did at Riverbank, the wall assembly that they tested, which supposedly had a thick layer of this "acoustic paint" on it, produce the amazing result of STC-52! Imagine that! On the other hand, according to page 142 of IR761, the normal rating for a wall built the exact same way (except for the paint), is STC-51. So this rather expensive product managed to improve the STC rating by a whopping 1 entire point. Imagine that!!!! Practically nothing at all. No human would notice the difference. And the exact same wall with just a coat of ordinary house paint would probably give roughly the same result anyway.

So when they claim that the PAINT gave an STC rating of 52, well, that's not exactly telling the entire truth, now is it? The entire truth is that the complete WALL produced an STC rating of 52, as would any other wall built the same way and painted with pretty much any paint....


Even more curiously, comparing the TL curves from IR-761 and this painted wall, the paint actually makes the isolation WORSE between about 400 Hz and 2 kHz! For example, the IRC wall gets 67 dB at 1,250 Hz, while the "magic paint" wall only gets 54 dB! That's a huge difference. So mid-range sounds would get through that "magic paint" wall about 300% BETTER than through a similar but unpainted wall.... In simple terms, subjectively, speech would be heard about 3 times louder through the "magic paint" than through an unpainted wall.

Compare the TL data:

Frequency --- Plain --- Magic
400 Hz. --- 53.3 --- 49
500 Hz. --- 56.5 --- 50
630 Hz. --- 60.6 --- 52
800 Hz. --- 63.7 --- 53
1000 Hz. --- 65.9 --- 54
1250 Hz. --- 66.9 --- 54
1600 Hz. --- 63.0 --- 55
2000 Hz. --- 52.3 --- 53

Hmmmm.....

(The coincidence dip is also curiously absent... That's hard to explain!)




And of course the test results are invalid anyway, since they did NOT test the wall both before and after painting it. They only tested after, so there is no indication at all as to what effect the paint had. An honest test would have been to take along several wall samples, all built different ways, test each of them first without paint, then test again with paint, and publish the results for everything.

I wonder why they didn't do that?


Sigh!


- Stuart -

[BriHar]

Yes the 'Data' leaves a lot to be desired, but the Product manager has finally seen the light, and instead of trying to argue the point with many well known acoustical engineers, that they will only make the complete test results available to potential customers, has finally agreed to post the complete data.

The general consensus of the aforesaid said engineers seems to be that it may in fact be useful for soundproofing in some situations, but almost definitely not for studios.

Rather that describe the details here I'll simply give the link to the forum posting over on GS
http://www.gearslutz.com/board/studio-b ... paint.html
I think you'll find it very interesting.

[Manning]

Fans of this paint will probably be pleased to know that I'm about to commence selling acoustic panels made from the very same fabric used in the highly successful Mystic Mayan Power Cloak.

http://soul2soultreasures.com/mayan_cloak/

[RJHollins]

Fans of this paint will probably be pleased to know that I'm about to commence selling acoustic panels made from the very same fabric used in the highly successful Mystic Mayan Power Cloak.

http://soul2soultreasures.com/mayan_cloak/

Possibly a stylish 'Clothing Line' in the future

[Soundman2020]

The general consensus of the aforesaid said engineers seems to be that it may in fact be useful for soundproofing in some situations, but almost definitely not for studios.

Thanks for the link! I just saw that, and it is indeed interesting. But as you point out, no use at all for studios. And depending on the total cost of applying it, there might not be much of a reason to use it at all, even if it does work. But the conclusions are unexpected, I do have to admit that. For that small range of frequencies in the high mids, it actually does have a slight effect.

And after seeing their demo on YouTube, I reckon I really do need some to silence all of my Tupperware! My lunch sandwiches just make way too much noise. So annoying...


- Stuart -