Curtians vs Soundboard

[m00n]

Fini,

Yes, AIM is free.

You can download it here

Well it's free for the Windows platform anyway.

BTW, be careful though with your daughter. There are lots of creeps out there. I don't know all the details, but my wifes boss's daughters keep getting in trouble at home for using chat programs, then meet guys on them and make secret little arrangements to meet personally with them... Be a watchful parent.

Good luck!

[fini]

Thanks! Yeah, that's scarry stuff. Our computer is in the family room, so those using the computer aren't isolated. In fact, my youngest (11y.o.) daughter is watching me type this RIGHT NOW!! Here she is...

Hi I am appauled by what your wifes boss's daughter does but my sister can just meet boys at school ( but she doesn't do that...yet)!!!

fini & daughter

[m00n]

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On 11/20/2002 2:41:09 PM fini wrote:

Hi I am appauled by what your wifes boss's daughter does but my sister can just meet boys at school ( but she doesn't do that...yet)!!!

fini & daughter

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That's right, let her meet nice boys at school, NOT wackos over the internet! Now that's not to say that everyone on the internet is a wacko, just that you should not take any chances, because you never know.

[artto]

Im not so sure you want to use soundboard as a bunch of flat panels spread around the room. These products, such as Celotex, generally have a tendency to absorb frequencies that you want to retain in a sound room or home theater. They are designed more for noise control in work or commercial/industrial environments. They will basically suck out a lot of the midrange & make the bass sound humpy and bloated. This link has specs for a variety of Soundboard products of the kind you are contemplating. http://www.us.bpb-na.com/wall_panel_products.html .

I think you also dont want put a lot of soundboard on the front wall. Klipsch speakers dont seem to like dead sound absorbing surfaces around them. Ive also had a lot problems with dust from the Celotex panels so covering them is probably a good idea. That link above has these panels available ready made with various fabric coverings.

Sonex makes some nice materials for acoustical control http://www.mhtc.net/~lowey .

Curtains will have more of an visual impact than an acoustical one. Natural & synthetic materials used for curtains are relatively transparent acoustically. Consider the case of a heavy tarp covering some speakers at an outdoor festival. How much does it knock the sound level down? Almost nothing. And they obviously dont have the mass to even begin effecting lower frequencies.

What you are really trying to do here is control the distribution of sound so there are no hot or dead spots, at least in the listening area. Consider how the best sounding concert halls in the world are built. Lots of reflective and/or ornate surfaces, curves, angled flat surfaces, etc. to uniformly disperse the sound equally at all frequencies. The smaller the room is, the more difficult this is to do. Under all circumstances, AVOID CONCAVE SURFACES. These will simply focus the sound to a single (very) hot spot. Convex polycylindrical surfaces are ideal.

artto

[artto]

This pic might help. Not sure if its worth a thousand words or not, lol

artto

[m00n]

Hey artto,

WOW!!! I am very glad you made this last reply of yours. It really told me a lot. Three things in particular

1) Curtins will have little impact if any on sound quaility. This is very good news for me because I really want to hang curtins. And if I understand you correctly it should be fine. (depending on the type of material)

2) Don't put soundboard directly beind my speakers. So what I am thinking now to help with overall soundproofing would be to mount the soundboard directly to the studs, and put the sheetrock over that.

3) Too much soundboard is bad.

Oh and I guess a 4th would be I need to look into the links you provided.

Again, thank you very much... I am glad I found this out about soundboard. I knew it would absorb sound, but I thought that was a good thing. I suppose it's going to be a good idea to have a professional come out and speak with me about where my room needs panels and what not.

question You said it may not be a good thing to put soundboard behind my front array of speakers, what about the back wall? Can that be plastered with soundboard? Or again, should I put the soundboard behind the sheetrock?

BTW, is that a pic of your room? I don't think I will go that extreme, but I bet it has nice sound quality features.

[m00n]

So, I was over at http://www.mhtc.net/~lowey/SONEX%20Ceilings.htm looking at the tiles, are they really worth $27.50 per each tile? Are there cheaper yet just as affective alternatives?

[artto]

Correct. The curtains will have very little impact on sound quality. Many years ago, when I first bought my K-horns, we still lived in an apartment (obviously I had future plans for these things). The room was only about 12'x14'. I hung medium weight curtains across the back wall. The curtains had to be "bunched" up...the pleats compressed rather tightly for it to have any impact at all. You could still hear the "ping" between the walls when clapping your hands. There's nothing wrong with a "live" room as long as the reflections are well controled & uniformily dispersed with regards to all frequencies (thats the objective anyway). For what its worth, the reverberation time for a room is generally given at 500Hz, but depends on its intended use & volume (size not loudness). Recording studio listening rooms usually have around 0.4-0.5 second reverberation time. But as I stated above, of particular importance is the avoidance of "piling up" of room resonances which is what diffusers (as opposed to sound absorbers) accomplish so well.

You can put the sheetrock over the soundboard. Its more effective if you have an air space 1-2" between the two. Also take a look at Sonex's ProSpec barrier as a layer between the sheetrock & the studs. Bass is going to be the most difficult to handle & that means wall mass to block sound transmission.

My room's previous "setup" had a lot of Celotex "tiles" & Sonex panels on the back walls & ceiling areas. I came to the conclusion that the room was overstuffed. Be careful with the sound absorption. Don't over do it.

Sonex is somewhat expensive. I bought mine in standard grey, in bulk (a whole box) from a local professional sound contractor. Saved a lot of money. But yes, its worth it. Sonex is unique in that it is an "open-cell" foam. Its acoutically dead. The thicker it is, the lower the frequencies that can be absorbed. Only the geometric structure of the cell(s) is retained. There is not "membrane" between the cell structure as in regular closed cell foam. Sonex is basically 99.9% hollow. They make it in different thicknesses & patterns/shapes for different applications. There are some other companies making something similar now. Just make sure its "open-cell" acoustical foam, not some crap they use for egg cartons or packing material.

And yes, thats my room. The flash kind of washed the room's lighting out & makes the panels look like there is less depth between them than there really is. It may be a few weeks or months, but I'll post something that is more representative of what its actually like "in the room".

artto

[m00n]

artto

You may not have caught other posts of mine, but you mentioned an air gap. Actually in Jan when I start my reconstruction project, I will be doing just that. On my two end walls, I am actually going to be building 2X4 sound barrier walls in front of the existing exterior one. I will be leaving about a 1" air gap between them. Filling the studs with insulation. Actually someone was telling me that there is a type of styraphome(spelling?) that can be used between the studs that would work much better. I need to check into that. So when I was referring to putting the soundboard behind the sheetrock, I was referring to putting in on the second new.

So, I have a web site but I have not maintained it plus I think I hosed up my internet server, I will get it up and running and you can see some of the pics and see what I have to work with....

Again, thanks for all your help.

Rick

[artto]

There sure are a lot of misconceptions out there. I would question the use of styrofoam as a sound barrier/absorber. It is lighter in mass than either gypsum wallboard, Celotex rigid insulation, or lath & plaster. That means low frequencies will go right through it. Technically, you shouldnt even have any mechanical connection between the interior wall surface & the wall structure. There are resilient lath channels that can be used for this purpose. Its called discontinuous construction & there are many ways to achieve this. There also used to be a product called Acousti-lead (sheeting) that could be used between the wall layers. Sonexs new ProSpec Barrier provides better performance in a similar product & is probably much safer. You dont really need to fill the air space between the studs with insulation. Insulation is mostly porous & light & will affect only the highest frequencies (of which there are relatively very little, and even less that made it into the wall). Keyword(s): Diffusion. Isolation. Mass. Sound absorption comes after all those other things are in place.

Exterior & interior noise can produce 3 types of sound problems: (1) multiple reflection of airborne sound within a room, (2) airborne sound transmission through walls, floor/ceilings and openings, (3) structure-borne (impact) sound transmitted primarily through floor/ceilings and from vibration of mechanical equipment and plumbing systems.

Highly reflective, hard surfaces, especially flat parallel surfaces can cause airborne sound within a room to build up to annoying levels - even higher than that of the original sound source (ever notice how that table top radio, or the TV set sometimes seems louder after its been on a few minutes & you reach to turn it down?).

It is impractical & uneconomical to obtain sound level reduction within a room of much more than 10Db by treating reflective surfaces with sound absorbing materials. For example, a typical ceiling covered with acoustical tile provides a sound level reduction of only 5-7Db, yet the reduction is clearly audible. In others words, dont over do it. All you are going to accomplish is the need to turn up the volume even higher. And with higher volume comes higher distortion.

[jtkinney]

Some good suggestions here. If you want to know about different materials, go buy "Master Handbook of Acoustics" by F. Alton Everest. Amazon has it in stock for $18.92. It has everything you every needed to know, and a lot you didn't.

Artto, nice room, wish I had that much width.

[artto]

Thanks Jim. A lot of the info I used was published by Klipsch in their "Dope from Hope" newsletters & "Audio Papers" also from Klipsch. I have no idea if these are still available.

I'm also probably somewhat at advantage because I have a background in architecture & have studied both interior & landscape acoustics. Consequently, I also use my professional reference books on the subject which covers various construction methods & has all the sound absorption coefficients for various materials & types of construction. If you're near a University with an architecture department you can probably buy these books at the University book store. Their library should have them too.

One I refer to frequently is "Construction. Pricipals, Materials & Methods" Schmidt Olin & Lewis. Published by the United States Saving & Loan League.

I doubt it is still being published either. But there should be something similar available.

And then of course, there's your own ears. I must admit, that the way the room was orginally setup equipment wise & acoustical treatment, did not produce the best results. And in some ways, certain things are now completely the opposite. So experimentation is key.