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Walls & Ceiling-Diffusion or Absorbtion?

Posted: Sun Sep 07, 2003 4:33 am
by blackdrum
Hi,
What would you guys recommend for:

control room 9ft x 13 ft (8 ft celing)(floor will be carpet)?

live room 13ft x 17ft (9 ft ceiling) (floor will be vinyl)?

im looking to 'tune' the rooms.

Thanks!

Re: Walls & Ceiling-Diffusion or Absorbtion?

Posted: Mon Sep 08, 2003 9:08 am
by giles117
blackdrum wrote:Hi,
What would you guys recommend for:

control room 9ft x 13 ft (8 ft celing)(floor will be carpet)?
No Carpet on the floor.

I'd Do the Control room in this design

http://www.saecollege.de/reference_mate ... ge%202.gif

What is your floorplan? Do a quick mockup

I think I responded on your other thread "vertigo"

This link above is from the SAE sight.

Finally, the design of these room is "tuned" for lack of a good way to say it.

Bryan Giles

Posted: Thu Sep 11, 2003 12:39 am
by blackdrum
Thanks for the reponse!

Should I rip up the carpet in the control room? (its the thin cheapo industrial blue stuff.)

Other people have suggested not to go w/ slot resonators in the control room because it is so small.

Do you think i should build them or just use fiberglass insulation?

another person suggested to just go around the room with a mirror, and place fiberglass or foam panels wherever i could see my tweeters in the mirror.

Ever hear of this method?

Thanks Again!

Posted: Thu Sep 11, 2003 4:21 am
by giles117
I would build them, the help minmize/control flutter echo in the room, All Fiberglass does is absorb, will not stop flutter echo.

Johns wall mounted one are nice, and take up very l;ittle space. Like I said elsewhaer, My Room was 10x13, and with everything built doesnot feel to small to me.

The Mirror thing is interesting, but I have built a room to Johns specs and it works. trust what works.

Bryan Giles

Posted: Thu Sep 11, 2003 6:07 am
by knightfly
Actually, the mirror trick would also work in John's designs - the point of the mirror trick is to identify early reflection paths, that is, sound paths to your ears (other than direct ones) that are less than about 22 feet longer than the direct path to your ears from your speakers.

The reason the mirror trick would work in John's designs, is that RFZ, or Reflection Free Zone, is all about re-directing early reflections AWAY from the listener until they've had at LEAST 20-25 milliseconds of delay; this is accomplished by the splayed walls and sloped upper front wall/ceiling design.

In rooms that are small enough NOT to have a minimum ROUND TRIP path from mix position to rear wall of at least 22-25 feet, it's not recommended to use diffusion on rear walls but use absorption instead.

Building slots for front of room is fine, as long as they are splayed enough to redirect sound away from the mix position. Their advantage, besides trapping specific frequency ranges that could cause problems, is that they don't totally deaden a room which may already have too much absorption, depending on what OTHER treatment has been done... Steve

Posted: Fri Sep 12, 2003 1:57 am
by Ethan Winer
Bryan,

> All Fiberglass does is absorb, will not stop flutter echo. <

Say what? In a room that small and without angled walls, fiberglass is the only viable way to stop flutter echoes.

--Ethan

Posted: Fri Sep 12, 2003 3:40 pm
by blackdrum
this is good stuff....keep going!

so on the back wall, do i want foam or fiberglass or what?

what about the floor? i hear some say rug is ok for control room, some say its not? whats the deal?

we are also ready to install the glass window. we found someone who will put in a window in each wall (2) for $250USD. anything i should know befor we go ahead?

thanks!

Posted: Fri Sep 12, 2003 9:59 pm
by giles117
Really Ethan. Hmmm So just putting an absorptive material on parallell walls will stop flutter echo?

Aww man you have ruined everything I have learned over the past 7 years. Back to school I guess.

All absorption does is reduce, it does not eliminate. Man You and barefoot burned up a few threads debating this about 4 months ago.

You need the angles regardless blackdrum, that is specifically why I believe John came up with his portable DIY designs that take only about 4 to 8" from either side of your room to implement.

Maybe I have been mixing in too many bad rooms that had treatment placed on parallel walls and Now I got it good I want others to enjoy what I have.

Oh Well, so much for wanting the best for others....

LOL

Anyway......

SO I have to disagree with you again Ethan.

Bryan Giles

BD, if you do JUST fibreglass you will find down the line that your mids just ain't accurate enough.

Enjoy the weekend Fellas....

Posted: Sat Sep 13, 2003 2:06 am
by Ethan Winer
Drums,

> so on the back wall, do i want foam or fiberglass or what? <

In a control room that small you want absorption in the rear. Foam works, but fiberglass is better, cheaper, and fireproof. Though fiberglass is more hassle because you have to cover it, and it's less pleasant to handle.

For either material, the thicker it is, the lower in frequency it absorbs to. This is the real issue. Foam that's only half an inch thick will still absorb 100 percent above 1 or 2 KHz. As the material is made thicker, and optionally spaced away from the surface it's mounted to, the absorption extends to lower frequencies.

> what about the floor? <

It depends on what's on the ceiling. For small rooms I prefer an absorbent ceiling and a reflective floor. Expensive wood tiles are good, but so is cheap linoleum and even bare or painted cement.

So what's best depends on your budget and how much you enjoy doing grunt labor and construction. :D

--Ethan

Posted: Sat Sep 13, 2003 2:10 am
by Ethan Winer
Bryan,

> you have ruined everything I have learned over the past 7 years. <

I'm so sorry! :D

> You need the angles regardless blackdrum <

I'm sure that's the ideal solution. Whether he will do that remains to be seen. If not, what do you recommend other than fiberglass? :twisted:

--Ethan

Posted: Sat Sep 13, 2003 2:49 am
by giles117
Well Ethan, when you got me you got me. :D

If he doesn't take the advice we give then what. LOL But I think he will.

Bryan Giles

Posted: Sat Sep 13, 2003 2:50 am
by giles117
You know I thought of an answer. He could always move to the country, clear out a nice wide area and mix outside. :D

Man this is gonna be a good weekend. I am having too much fun laughing all over the place.

Bryan Giles

Posted: Sat Sep 13, 2003 10:13 am
by blackdrum
HI,

thanks for all the responses.

the ceiling is drywall (gypsum)....what should i do about that?

also, we have a lot of leftover rockwool. could i use that in place of the fiberglass?

thanks again!

Blackdrum

Posted: Sat Sep 13, 2003 7:29 pm
by giles117
Yes you can use the rockwool in place of the fibreglass inside your resonators, etc.. But for surface mounted uses, depending on your brand of rockwool, I'd use the fibreglass as it is more rigid and stays together better.

The Roxul Wool I use is not as sturdy as say OC-703 Even though it is as dense 4pcf.

Note: I managed to get my hands on some old OC- Mineral wool and it was much more sturdier than the Roxul I was using though they were evenly effective.

Bryan Giles

Posted: Sun Sep 14, 2003 2:18 am
by Ethan Winer
Bryan,

> when you got me you got me. :D <

I'm not trying to "get" anyone, just keep things practical and on-topic. :)

> He could always move to the country <

I've been arguing for a few weeks with some guys over in rec.audio.tech about the suitability of using DSP to solve room acoustics problems. These folks keep insisting that DSP alone can solve every possible room problem, so there's no need for acoustic treatment. What they overlook completely is the practicality of that approach. Yes, DSP can fix everything, but only for an area of one square inch! My wife would just love that. "Honey, if only you were sitting here, instead of next to me, you'd just love the way this movie sounds!"

--Ethan