Effective Volume.

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longsoughtfor

longsoughtfor

Searching for the sound
In another thread recently Bigfoot made mention of increasing the effective volume of a room. This is naturally accomplished by absorption. I've looked around and have not found a reasonable explanation of how this is calculated. I.E. if I add X ft/cm of type Y insulation how much does that increase the EV of my room?

Any thoughts?

Kevin.
 
Effective volume?

Howdy longsoughtfor, say, I'm no expert on this recording studio stuff. Hell, I'm in acoustics 101 and just a student. And all I have for this is another question. What is it. I've never heard the term, or the theory, if thats what it is. Is this something all studios try to achieve, say like an RT-60 of some difinitive nature? Thanks, just trying to learn. Oh, BTW, does this have anything to do, with the "allison effect" that barefoot has been explaining on other threads? That one has me scratching my head:confused: Even though he explains it in laymens terms, I don't know how to interpret it in terms of what it means in regards to studio construction, and what it is you do with the knowledge once you understand it! Boy, if there was ever a subject that that can turn your head inside out, its acoustics:eek:
fitz
 
In the thread: https://homerecording.com/bbs/showthread.php?s=&threadid=61417

Barefoot says:
The depth of the control room is about 13ft. You're right, it's not ideal. But I don’t think it's TOO short, especially if the area directly behind the listening position is covered with QDR diffusors (which are not terribly difficult to build). With respect to low frequency performance, the effective volume of the control room will likely be even larger than your design.

I have heard the term befor with relation to speaker design. By stuffing a speaker cabinet with insulation or other fiber, you can increase the effective volume of the box.

I was just wondering how the concept applies to room design.

Cheers
Kevin.
 
Quadratic Residue/Primitive Root Sequence'

Hello, can anyone enlighten me on this subject. I have read Mr. Everests Book, but not being a math oriented person,:rolleyes: leaves me looking for a flashlight in the dark. I understand a few of the concepts, but the width, depth ratio of the individual steps are a little vague for me, especially when you try to change these for other frequencys. And if this isn't even relevant anymore, please ignor this. I know Mr. Sayer has a different philosophy in regards to using diffusers on the control room rear wall. I am interested in the current use of these in the tracking/vocal rooms. Not so much in the control room. From what I've read, the RPG will sonicly "enlarge" small rooms. If slat resonators, are of more importance in regards to diffusion(the slats reflect don't they?)these days, then again, please ignor my ignorance of present day theory or preference. As I have access to an architectural mill, I thought these would be interesting to build out of special materials that I have also access to. I just don't want to waste time on guessing the math and end up with quasi bullshit, that, although may look nice, is in effect a joke. Like Mr. Sayer said, he's seen many LEDE demos because of this. Any input on this would be appreciated. You know, its awfull feeling stupid asking this stuff. I don't like coming off as an idiot. But when it comes to acoustics, I am.
fitz:)
 
Opps

Sorry, I meant to start a new thread.:o I don't know how to change it now. What a dunce, huh!
 
I'll take a crack at it. The way to figure out the sequence for a prime residue difuser is this:

Pick a prime number. I used 7

List the numbers from 0 to your prime

0 1 2 3 4 5 6 7

Square them all.

0 1 4 9 16 25 36 42

Find the closest even multiple of the prime lower then the squares above.

[0 1 4] 7 14 21 35 42

Subtract these numbers from the squares [excpet these since they were lower then the prime (?)]

0 1 4 2 2 4 1 0

That is the depth sequence of the wells. The 2 2 is the center. And I belive the 1 is the width.

I ended up fudging the width on mine a little to match the wood I had. But it does sound OK.

Why & how these work exactly I'll leave to someone else to explain.

Kevin.
 
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