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Postby Eric Desart » Wed Apr 19, 2006 12:35 pm

Hi Flaviu,

Basically, while I understand you being curious about the RT, that RT is valid for THAT room.

As well John in his Room mode program as well Jonessy have a mathematical approach in their respective tools, based on formulas I designed end the eighties (copyrighted stuff and I mean that).
Hence use either of those and you can find a target RT in function of Volume and Shape of your room.

What I made is a live room, as live as I could, without loosing definition (with somewhat variable acoustics and RT), which for me gives another RT than your target in your live room.

  • If I have 1.8 sec in the Galaxy Hall, I have a good Live Room. Above 2 sec It becomes a very sensitive room, in my eyes not suitable for large setups. For full orchestra setups > 2 sec their = hell (we can go to +/- 2.2 sec). They don't hear one another loosing definition/feeling when they have to drop in (timing difficulties). They are exhausted in no time. 1.5 to 1.6 sec is better.
  • If I have 1.8 sec in the Antwerp main Cathedral I have a Dry room.
  • If I have 1.8 sec in this current room I don't have a Live room but plain living hell, more sounding as a completely untreated swimming pool.
    Hence this room for me allows me to check those relations a bit more and play a bit with it in function of setup.
Warm regards
Eric.

PS:
The fun part of the above lead story is that he got a dry description and a reason beforehand even referring to this mass.
With the way they live and feel, my words didn't get through at all, numbers hardly mean a thing.

But when he got that in his hands, trying to lift that from that counter (or wherever they put it on), only then he felt contact with this reality and it became one, and even didn't notice, remembered or felt that my words and exact numbers represented completely the same reality.

Hence, his natural instinct was: I must warn Eric here, I must tell him.
.
Last edited by Eric Desart on Wed Apr 19, 2006 1:35 pm, edited 2 times in total.
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Postby Eric Desart » Wed Apr 19, 2006 1:18 pm

J.F.Oros wrote: so I'll have the chance to play a little with some ED™non-scotties, (or polys, or poly's, or whatever ..., but not police please  :mrgreen: )


:)  Let's continue calling them Scotts Polys, always liked that name, and Scott explained soooooooooooo many people how to make them.
:twisted:  And if he mentions money again, just play deaf ....

Or if we want to call them (what was it?) Hyperfusors or something, it's OK, but should be Scotts choice.
Historically it are Scotts.

And mine are deviating designs: hence "Raped Scotts Polys"

:mrgreen:
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Postby J.F.Oros » Wed Apr 19, 2006 1:47 pm

I knew I had to wait some time before replying to your message, it looks better now (but usually the first versions contain more info, before being censored)  :mrgreen:

Of course I know that the optimum RT varies with the specific volume, form and application of the room and I will for sure try John's and Jonessy's programs (hey, "John & Jonessy" sounds cool for an acoustics consulting firm name  :D ; or maybe a law firm ?)
I already started to play with your room modes calculator looking for the target RT curve on different dimensions.

This reverb time business starts to interest me more and more, because lately I was solicited on consulting/measuring for rooms quite large (even for the Romanian National Opera Hall, that we had fun about in some early thread  :D), and I face myself with the need to study and try to understand standards (like the ISO-3382) and all kind of large rooms parameters (EDT, D50, LF, BR, etc.), and more important the practical implications of their various values.

Maybe I should buy Beranek's book (Concert Halls and Opera Houses).

PS: and those Hippie-Fusers™ sellers will not get a dime from me, I opted for the Open-Source polys  :mrgreen:
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Postby Eric Desart » Wed Apr 19, 2006 3:46 pm

J.F.Oros wrote:I knew I had to wait some time before replying to your message, it looks better now (but usually the first versions contain more info, before being censored)  :mrgreen:


:twisted:  I really become tooooooooo transparent here.

The idea was not that you followed my edits, but that you read only the result after an hour or so.
1) I write the base
2) Then expand telling as if I should to somebody sitting next to me, I know very well.
3) Then notice this is public.
4) Start removing stuff ....
5) ......
6) Try to clean it up, making it readable
7) ......

:mrgreen:  I really must change my ways here, using Word or something and then copying it in the Forum.
I'm really no good at this ....

I'll use Bert's style in the future (much faster see 3 following in-depth analysises):
1) :mrgreen: I Don't trust those guys

2) :mrgreen: Don't trust RT.

3) :mrgreen: And the rest neither
.
.
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Postby bert stoltenborg » Wed Apr 19, 2006 4:28 pm

I don't trust anything.

Let's start an OT on global warming, or integrety of politicians, or journalism, or scientific research.

:mrgreen:  :mrgreen:  :mrgreen:
If you view life with the knowledge that there are no problems, only opportunities, you are a marketing manager.......this is my personal philosophy
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Postby bert stoltenborg » Wed Apr 19, 2006 4:29 pm

I'm an indepth analyzer.
If you view life with the knowledge that there are no problems, only opportunities, you are a marketing manager.......this is my personal philosophy
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Postby Zaphod » Wed Apr 19, 2006 4:33 pm

I don't trust OT  :mrgreen:
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Postby J.F.Oros » Wed Apr 19, 2006 4:45 pm

Eric Desart wrote: :twisted:  I really become tooooooooo transparent here.

A disciple has to learn his Master's ways  :mrgreen:

:mrgreen:  I really must change my ways here, using Word or something and then copying it in the Forum.
I'm really no good at this ....

I use a lot the preview buton on the post editing window, before actually sending the post  :)


bert stoltenborg wrote:I don't trust anything.

Hehe, this is like :
"I don't trust myself, and I can't trust you guys either because you can trust a guy like me !"

:mrgreen:  :mrgreen:
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Postby avare » Wed Apr 19, 2006 5:16 pm

Bob wrote:Avare:

Remember this: http://forum.studiotips.com/viewtopic.php?p=17646#17646
( i.e. "3 times wavelength" is similar to "7 feet", for, as you put it, "THOSE DIFFUSERS" )


Yep, completely... after goin back to the thread :D .  Consistent with the obfuscation of the underlying theory (that rolls off the tongue so nicely.  Thanks Scott!).

Adding to the two points in my first post in this thread:  point 3) the relatively unrecognized use of diffusers to reduce initial reflection intensities.

Non-pedanticaly eschewing obfuscation:
Andre
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Postby Scott R. Foster » Thu Apr 20, 2006 1:12 am

You are all so mean...

Bert and I offer up the Hippyfusers with nothing but love in hearts and yall just abuse us.


:roll:
SRF
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Postby Eric Desart » Thu Apr 20, 2006 8:42 am

Scott R. Foster wrote:You are all so mean...


Come here you .....
Image
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Postby Eric Desart » Thu Apr 20, 2006 8:50 am

..... and Bert

Image
.
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Postby bert stoltenborg » Thu Apr 20, 2006 9:33 am

We gonna die popular but poor, Scott.

:lol:
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Postby J.F.Oros » Thu Apr 20, 2006 10:27 am

bert stoltenborg wrote:We gonna die popular but poor, Scott.

:lol:

I wish I could grow old and die popular but poor, in a place like Scott's paradise garden, with a girl like M at my side.  :mrgreen:
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Postby Terry Montlick » Thu Apr 20, 2006 2:05 pm

Eric Desart wrote: ...
As well John in his Room mode program as well Jonessy have a mathematical approach in their respective tools, based on formulas I designed end the eighties (copyrighted stuff and I mean that).
Hence use either of those and you can find a target RT in function of Volume and Shape of your room.
...

Hi Eric,

The relationship between room size and "optimal" reverberation time is fascinating. The earliest paper I have on this subject is from 1926, and it references earlier research! Yet I don't think the phenomenon has been adequately studied to this day. Relatively recent work points to reverberation time as the critical cue for knowledge of room size. And yet without a perception (presumably visual?) of room size, we don't have a proper feel for the liveness of the space. Talk about circular reasoning! :bang

Regards,
Terry
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Postby Bob » Thu Apr 20, 2006 3:28 pm

Terry Montlick:

[humor]

recent work points to reverberation time as the critical cue for knowledge of room size


So if one is a minor bureaucrat with delusions of grandeur and a small office, then putting in a microphone/speaker/reverb-unit will leave visitors saying "Oh. My. This is a nice office."
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Postby Eric Desart » Thu Apr 20, 2006 6:31 pm

Terry Montlick wrote: Hi Eric,

The relationship between room size and "optimal" reverberation time is fascinating.......


Terry,
I'm well aware that a simple mathematical approach, can't cover all influencing parameters.
Hence I certainly should not advice to use it for projects as huge theaters, concert halls, operas etc.

Already long I thought to write about it.
But I use this approach very long already, it's integrated in software used by the Catholic Univ Leuven here. Rockwool used it to rate the projects from there acoustics division Rockfon etc.

I started (half the eighties) with a strict Volume related approach in fact directly comparable with the formula you find here.
http://www.aes.org/technical/documents/AESTD1001.pdf

That formula is a simplified version of what I used second half the eighties with an adjustable Reverberation Factor to cover not only one type of room or purpose.
Later (end eighties/begin nineties can't remember exact dates but can find that all back), I noticed that with higher RTs, ignoring the shape of the room could give significant undesirable results.
Hence I reworked that approach, and checked it with lots of real live projects, discussed it at the Univ etc.

Now I standard work with concepts as Reverberation factor and Room Shape factor.

But I know that simple mathematical things can't cover all parameters in such a complicated business.  :wink: Hence it's not the magical answer to whatever situation, not at all.

Still, the formula published by AES in 2001, was used by me already second haf the eighties in a more extended form covering not only CRs, and I improved the method end eighties or begin the nineties (and kept playing with it).

Warm regards
and glad you're here

Eric

And I'm no good at dates. My mind becomes a cheese, certainly for things who don't really matter to me.
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Postby Terry Montlick » Thu Apr 20, 2006 7:15 pm

J.F.Oros wrote:This reverb time business starts to interest me more and more, because lately I was solicited on consulting/measuring for rooms quite large (even for the Romanian National Opera Hall, that we had fun about in some early thread  :D), and I face myself with the need to study and try to understand standards (like the ISO-3382) and all kind of large rooms parameters (EDT, D50, LF, BR, etc.), and more important the practical implications of their various values.

Maybe I should buy Beranek's book (Concert Halls and Opera Houses).

In another of Beranek's books (my favorite, long out of print  -- I bought a first edition at the Harvard Coop when it was still sold new in the late 1960's :8 ) "Acoustics," 1954, McGraw-Hill, ISBN 07-004835-5, he gives a really cool graph of  room volume vs. room constant R in sq. ft. But I think the best thing about this graph is Beranek's own subjective rating of room liveness, which he expresses in terms of average absorption coefficient:

0.05 - live room
0.10 - medium live room
0.15 - average room
0.25 - medium dead room
0.4 - dead room

Sure, very simplistic, but oh so elegant!!! :D
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Postby avare » Thu Apr 20, 2006 7:35 pm

Terry Montlick wrote:In another of Beranek's books (my favorite, long out of print  -- I bought a first edition at the Harvard Coop when it was still sold new in the late 1960's  ) "Acoustics," 1954, McGraw-Hill, ISBN 07-004835-5


I knew you had depth to your character!  Not only are you are a master of one of most interesting scientific fields (acoustics of course), you are also an admirer of the great literary works of our time!  It is one of my favourites also.  At times it is by bedside, right along with the...uh...  the other books and magazines at my bedside. :)

Wildly diverse also:
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Postby Eric Desart » Thu Apr 20, 2006 8:30 pm

Terry,

Maybe you knew, but that book is taken over by ASA:
http://asa.aip.org/books/acoustics.html

I've an edition of 1996
It mentiones the original 1954, 1986, 1990, 1993, 1996 editions

Eric
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