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MyRoom Acoustic Design
Old 2nd March 2011
  #31
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Thanks Andre, lots of info on that site and the links to be found there. Like this doc :
http://www.telfor.rs/files/radovi/TELFOR2010_09_24.pdf
So I guess we throw PRDs and QRDs in the garbage and henceforth adopt this new technology ?

Out with the old, in with the new !

(glad I haven't started building yet...)
Old 2nd March 2011
  #32
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Quote:
Originally Posted by PaulP View Post
Thanks Andre, lots of info on that site and the links to be found there.
Yes, Thomas and Fran's site is great.

Quote:
Like this doc :
http://www.telfor.rs/files/radovi/TELFOR2010_09_24.pdf
So I guess we throw PRDs and QRDs in the garbage and henceforth adopt this new technology ?

Out with the old, in with the new !
I do not understand your statement. The rooms in the paper use diffusers of the phase grating origin.

Regardless, Enjoy!

Andre
Old 2nd March 2011
  #33
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Quote:
Originally Posted by avare View Post
The rooms in the paper use diffusers of the phase grating origin.
Yes, origin. I see this new form as a sort of new species that evolved out of the previous PRDs and QRDs.

The interesting thing is that it combines dispersion and bass trapping by letting sound through to the absorption layer behind. We no longer have to decide if we'll put absorption or diffusion at a particular spot, we can put both !

I'm just generalizing, and dreaming. I haven't spent the time yet to figure out if it really makes sense or not. I find the idea attractive though.
Old 2nd March 2011
  #34
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Paul,

The amplitude grating component of the design eliminates its usage for certain implementations. ISD termination for example.

A neat tool, but not a "better" tool necessarily. Just different. Figuring how the design actually works in terms of return/absorption is key.
Old 2nd March 2011
  #35
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Quote:
Originally Posted by PaulP View Post
The interesting thing is that it combines dispersion and bass trapping by letting sound through to the absorption layer behind. We no longer have to decide if we'll put absorption or diffusion at a particular spot, we can put both !

I'm just generalizing, and dreaming. I haven't spent the time yet to figure out if it really makes sense or not. I find the idea attractive though.
I understand your line of thinking now. Thank for clarifying it.

The idea of using space behind, or even in, diffusers for absorption is not new. There have design concepts for his on John L. Sayers site for years. Aslo, many lay people ignore that diffusers themselsvs provide absorption averaging around .2-.3. Cover a surface with diffusers and you have a lot of absorption. So much that the room would be considered dead.

Pleae do not misinterpret what I wrote above as diminshing the MyRoom design. It is a beautiful implementation of known acoustic "tools" to use the owrd John did in the previous post.

To give perspective on tools and implementation, I can get paint brushes just like Rembrandt's, and I can gurantee that I will never make art like he did.

Selectively artistically gifted,
Andre
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Old 26th June 2011
  #36
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Hello everyone, I'll try to explain whatever I can.

Quote:
Originally Posted by avare View Post
Thomas (Northward) has an execellent forum that he moderates about studio acoustics. A while ago Bogic Petrovic posted a link to the control room design concept that he and Zorica Davidovic developed MyRoom Design white paper. A fantastic development and much more public than Moulton and ZR Acoustics!
Quote:
Originally Posted by Max 002 View Post
It looks really good! Im going start reading it tonight...
Thanks! (to both of you)
Quote:
Originally Posted by Max 002 View Post
My question is how can you get around the racks and the surround speakers to actualy get to the workstation? It does not seam to have any room to walk by. :S
Yes, there is a bit tight... I have problem to walk between back speaker and rack (but I'm a fairly big - 2m - 120kg)... mixing engineer must be thin. ... there wasn't more space, and rack is really big.

Bogic Petrovic
Attached Thumbnails
MyRoom Acoustic Design-big_pic4.jpg  
Old 26th June 2011
  #37
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Quote:
Originally Posted by PaulP View Post
........

Nice place. A whole lot of work (and wood !) went into it. Sure get's the imagination going.
Thanks.
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Originally Posted by PaulP View Post
I'd like to know how thick the absorption is behind the diffusers. Can't be much more than 6" by the looks of things.
about 10cm-100cm (4"-40") if I remember good... for studio RES Media
Quote:
Originally Posted by PaulP View Post
Max asks a good question, I tried to find a door hidden among the diffusers but can't see any. Do you really have to move a speaker to get in ? Trap door ?
You can find door behind rack, as you can see at picture above.
Quote:
Originally Posted by 807Recordings View Post
Very Cool stuff and a great read.
Thanks.
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Originally Posted by 807Recordings View Post
I was not aware that you could place diffusors with absorbers. You learn something new every day.
It's mixed functions, if you have a small room... under 100m3 (3500ft3)... you dont have much space for both of diffusion and absorption... then... only way is to mix it. For wideband absorption you need a free air circulation, and for good surround reproduction you must have homogenous reflection planes for all five or seven loudspeakers... and diffuse sound field come to mind like best possible way.
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Originally Posted by PaulP View Post
Maybe the room is used for stereo most of the time.
It is... really.
Quote:
Originally Posted by Jeancab View Post
Very interesting link, thanks.

About the figures 8 & 11 and the AES limits, do you know what is the smoothing ?
1/3 octave
Quote:
Originally Posted by Max 002 View Post
I'm still holding on the idea of a possible hidden "Batcave" type door

Quote:
Originally Posted by Max 002 View Post

But Yea and they probably keep the surrounds stored in another room... But still its a pain to move the speaker everytime you want to go to the bathroom or ....
Yup... for PMC AML1 it IS a pain... with stands filled with sand...
Back speakers you can see at picture above.... they can be moved if needed, position is marked on floor. Also, we got a very good (stereo) listening position behind rack, where you can sit at bar chair... like you can see on attached picture below. Usually there is not need for anyone except mixing engineer to sit at main (surround) listening position.
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Originally Posted by Hannes_F View Post
No problem since this is the studio of David Copperfield.
lol!
Quote:
Originally Posted by Max 002 View Post
.....

So whenever he teleports while recording, does it cause any sort of interference in the signal?
Ummm...... this wasn't reported AFAIK.

Cheers,

Bogic
Attached Thumbnails
MyRoom Acoustic Design-dsc_2943_4_5.jpg  
Old 26th June 2011
  #38
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Quote:
Originally Posted by avare View Post
....Sorry, I know that is terrible grammer,
Sorry
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Originally Posted by avare View Post
but I do no se anything missing.
Yes, we tried to describe all basic principles but not design details that really isn't important.
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Originally Posted by avare View Post
Yes. This is dangerous to do if you are not a professional. heh
.......
Paper IS writen for professionals or skilled amateurs. heh

To all:
If there are more questions, please ask...

And, I don't really care if someone like to use hangers behind air transparent diffusers, or fluffy fiberglass... I have my preferences too, but this isn't important... basic principles of air circulation through diffuser and toward absorber that is "hidden" behind diffuser, and homogenous diffuse behavior in all directions except floor are important and define MyRoom design.

And to be clear, as I see some comments above, this principle is published to be free for all. No patent applications.

Best regards

Bogic
Old 26th June 2011
  #39
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Quote:
Originally Posted by johndykstra View Post
From what I can gather by visual and deductive (roughly 2' period, N13 with equal slat to slot ratio), It would seem the slat faces of the "air transparent" combo amplitude/phase gratings are approx 1". Would this imply that the diffusive return of such a device would only be composed of roughly 8k and up?
If I remember good, slats are 19mm thick/wide (~3/4")... and... slots between slats... hmmm... I really don't remember... but diffuser cells are about 60cmx60cm (2'x2')... then... you can calculate heh... if you like MORE detailed, BIG images... please ask... I have this
Diffusers has depth of about 10-12cm (~3-4")... this is about 1kHz of lowest working frequency.

Surfaces are veneered and coated with water based "something"... I can't remember.

Cheers

Bogic
Old 26th June 2011
  #40
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Thank you Bogic for taking the time to respond.

I would actually really appreciate more photos or info on the diffusor design. I think they are stunning.
Old 26th June 2011
  #41
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Quote:
Originally Posted by johndykstra View Post
......

I would actually really appreciate more photos or info on the diffusor design. I think they are stunning.
I'll try to prepare more pictures (800px) of RES Media later today. Still no pictures for Pressed Lizard, sorry.

Construction?
Diffusers in RES Media are made from (veneered) particle board, and in Pressed Lizard, diffusors are made from OSB... and they isn't veneered.

Both studios has double wooden frame construction similar to "room inside room", but without floating floor. First wooden frame have purpose to holds absorption behind air transparent diffusers, and second frame (surface) has purpose to holds air transparent diffusers.

Diffusers depths are usualy 10-12cm, except fractal diffuser in front of RES Media rooms.
That's all I remember now... and I think that it's easier to answer to more specific questions...

Cheers

Bogic
Old 26th June 2011
  #42
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Here's (more) pictures.

Enjoy.
Attached Thumbnails
MyRoom Acoustic Design-dsc_2918-.jpg   MyRoom Acoustic Design-dsc_2927_8_9-.jpg   MyRoom Acoustic Design-dsc_2970_1_2-.jpg   MyRoom Acoustic Design-dsc_2991_2_3-.jpg   MyRoom Acoustic Design-dsc_2933_4_5-.jpg  

MyRoom Acoustic Design-dsc_3007_8_9-.jpg   MyRoom Acoustic Design-dsc_3013_4_5-.jpg   MyRoom Acoustic Design-dsc_3016_7_8-.jpg   MyRoom Acoustic Design-dsc_3020-.jpg   MyRoom Acoustic Design-dsc_3021-.jpg  

Old 26th June 2011
  #43
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Diffuser calculations... I think all the time that it's obvious but if someone didn't catch how to do this, here is some hints:

1. Any pseudorandom sequence may be useful, we used Manfred Schroeder's formula, and you can use any practical order. (7, 13, 41...)

2. Diffusers are calculated like ordinary 1D.

3. slats for wells, that you will use anyway in ordinary 1D diffusers, are mounted equidistant from each other, with (air) gap between, and attached to frame.

4. width of gap between slats define level of transmited energy toward absorber.. (wider gap, more transmitted energy)... but...

5. ... gap between slats also define level of reflected energy (RT60) above 1KHz, and we find empirically that gap width between 80 and 120% of slat width, have good match with formula described in these documents:

1. "Multichannel surround sound systems and operations", AES Technical Council, Document AESTD1001.1.01-10, New York.
2. “Methods for the subjective assessment of small impairments in audio systems including multichannel sound systems”, ITU-R Recommendation BS.1116 (rev. 1), ITU, Geneva, 1997.
3. W. Hoeg, L. Christensen, R. Walker, “Subjective assessment of audio quality– the means and methods within the EBU”, EBU Technical Review Winter 1997, pp. 40-43.
4. "Listening conditions for the assessment of sound programme material: monophonic and two–channel stereophonic", EBU Tech. 3276 – 2nd edition May 1998, European Broadcasting Union, Geneva, Switzerland

...as you can see in our measurements.

6. Air transparent diffusers are combined phase and amplitude grating diffuser constructions

7. It's curious that slots between slats form a number of ports with random length of (hidden?) Helmholtz resonator (slat absorber) between two wooden frames, with wideband absorber inside.


hope this helps someone.
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Old 27th June 2011
  #44
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Pressed Lizard Studio.
Burst Decay Sonograms, measured at listening position.
Microphone is pointing toward acoustic axis of loudspeaker.
Dimensions of Pressed Lizard room (before any treatment) are:
width=3.56m, length=3.67m and height = 2.55m (w-11.7', l-12', h-8.4'),
Attached Thumbnails
MyRoom Acoustic Design-pressed_lizard-lch-sonogram.jpg   MyRoom Acoustic Design-pressed_lizard-rch-sonogram.jpg  
Old 12th July 2011
  #45
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I would like to say that I visited this room about year and a half ago..and that it looks great and sounds even better!!
I played a lots of material that I did in my studio in UK, and everything sounded as it meant to! Good translation of mixes.
The only thing I missed (comparing to mine studio) was feel of big speakers!
(I have Dynaudio M2 & Chord amp)
Overall vibe - great!
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Old 12th September 2011
  #46
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Quote:
Originally Posted by boggy View Post
Here's (more) pictures.

Enjoy.
I took my laptop over to my table saw so it could see those pictures. It spat a bunch of carbide sawblade teeth at me and brandished it's rip fence menacingly.
Old 5th February 2012
  #47
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Pressed Lizard control room was never completely finished from the aesthetics point of view, since it wasn’t a top priority. But the sound was always on the first place, and this is probably the best sounding small control room in my region.
The room is designed following MyRoom Design principles.


The left side of the room. Air transparent diffusers at the left side, at the ceiling, and above to the loudspeakers and a big LCD TV/monitor:






Front view from listening position:






Air transparent diffusion is a way to keep serious low frequency absorption, behind diffusers, virtually intact:







Front/side view. Both loudspeakers and a big LCD TV/monitor between (diffractions are suppressed this way). SM-3s allows full range sound field in a room at 115dB SPL max, without audible distortion, from about 4Hz to 25kHz:







This is the frequency response plot of the Pressed Lizard control room at the listening position. Left channel is blue, right channel is red:







SM-3, a custom monitoring system with DSP crossover.







Because room is very small, "room gain" appear to influence loudspeaker response below lowest room mode.






Full measured response is:







Pressed Lizard control room is described in our (already published) papers:

AES Convention paper: Davidovic Z., Petrovic B.: Acoustical Design of Control Room for Stereo and Multichannel Production and Reproduction - A Novel Approach, 129th AES Convention 2010, San Francisco, CA, USA

TELFOR Conference paper (english): Petrovic Bogic, Davidovic Zorica: A new acoustical design of control room for multichannel production and reproduction, 18th Telecommunications Forum TELFOR 2010, Belgrade, Serbia. [NEW]

Our white paper about MyRoom Design can be found here or here.
Old 7th February 2012
  #48
Gear Maniac
 

Hi Boggy, fantastic rooms!

I know you said that it is unimportant what material is used for the broadband absorbers but can I ask what material did you use ? Is it fibreglass. Also how thick did you make it ?

great work
Old 7th February 2012
  #49
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You know what would be quite interesting to measure.. spatial impression !

IAC or a similar parameter
Old 7th February 2012
  #50
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Quote:
Originally Posted by pacealmondo View Post
Hi Boggy, fantastic rooms!
Thanks!
Quote:
Originally Posted by pacealmondo View Post
I know you said that it is unimportant what material is used for the broadband absorbers but can I ask what material did you use ? Is it fibreglass. Also how thick did you make it ?
I used Philip Newell/Tom Hidley method for bass trapping (non-environment acoustic design). I'm pretty sure that simple but thick traps with fluffy rockwool will work... target is to dampen as much as possible room modes below 250Hz, before installing air transparent diffusers.
Old 8th February 2012
  #51
Gear Maniac
 

To say I'm impressed would be an understatement... I'm in awe! BTW, I've been thinking of doing a random binary pattern of strips of wood on top of my absorbers to see if it would help with some of my remaining response issues. Any thoughts on that idea Boggy?
Old 8th February 2012
  #52
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Quote:
Originally Posted by darkbuddha View Post
To say I'm impressed would be an understatement... I'm in awe!
Oh.. thank you very much! heh
Quote:
Originally Posted by darkbuddha View Post
BTW, I've been thinking of doing a random binary pattern of strips of wood on top of my absorbers to see if it would help with some of my remaining response issues. Any thoughts on that idea Boggy?
I doubt that binary diffuser over your absorbers will fix your (measured) response issues.
Better absorbers, or more of it, are better way, if your issues aren't from loudspeaker itself.
But binary diffusers at first reflections will help you to hear more detailed sound image, I mean, influence is more psychoacoustical, from my experience.
Old 8th February 2012
  #53
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Thanks. I've said it before, and I'm sure I'll say it again after this, but one day... one day I would LOVE to have a room treated like that. Functional and beautiful.
Old 11th February 2012
  #54
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Thanks for sharing all the precious information and knowledge, Boggy!

Two questions: there´s a minimal distance between the wood slats and the absorption to the diffuser works properly? And "If " the slats touches the absorption ... it defeats the purpose of the system?

Thanks again !
Old 11th February 2012
  #55
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Quote:
Originally Posted by ciro View Post
Thanks for sharing all the precious information and knowledge, Boggy!
You're welcome. heh
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Originally Posted by ciro View Post
Two questions: there´s a minimal distance between the wood slats and the absorption to the diffuser works properly?
I put 20mm thick cotton felt behind diffusers (it touches it). Next layer behind it, is Newell's panels.
I expect slight difference in low end absorption because different gap behind diffusers, but nothing spectacular.
Quote:
Originally Posted by ciro View Post
And "If " the slats touches the absorption ... it defeats the purpose of the system?
No, i have one layer which touches the absorption (20mm) and this works well...
It is better not to have loose "first absorptive layer" connection with diffusers, because it will form a membrane. This loose connection (touching) can generate very audible noise because low frequencies (I experienced that!). So use glue, small nails or staple gun to fix this connection.

Second thing that comed to my mind is to avoid tight connection and to build a small gap (5-10mm) behind air transparent diffusers.... but I think this will be less easier to build.
Old 11th February 2012
  #56
These rooms look 1) beautiful and 2) expensive. in fact they look so expensive that it surely would have been cheaper to move to a more suitably sized property. Could you fill us in on the financials for such a hi-spec finish?

All I thought that diffusors could not be placed in a repeated pattern without creating all sorts of strange artifacts, but all the wall panels look identical. Can you shed some light on this please.
Old 12th February 2012
  #57
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Quote:
Originally Posted by windmillsound View Post
These rooms look 1) beautiful and 2) expensive.
Thank you! heh
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Originally Posted by windmillsound View Post
in fact they look so expensive that it surely would have been cheaper to move to a more suitably sized property.
It can be better in "more suitably sized property" especially for surround, but not cheaper, I believe...
Quote:
Originally Posted by windmillsound View Post

Could you fill us in on the financials for such a hi-spec finish?
Financial costs depends a lot on labor costs, which varies from country to country. If someone can do all woodworking by himself, it will be cheaper (for him). With good drawings, support and CNC preparation it can be "DIYable", or at least, doable by woodworker.
If you look only at some common finished comercial diffusers, even if they aren't air transparent... this wouldn't be cheap at all.
At least, material costs may be from 20-100EUR per m2 of room treatment:
- dependent on type of material used for diffusers and its finish
- dependent on LF absorption which is needed in any type of design, already

For air transparent diffusers anything from cheap OSB to veneered and coated/lacquered particle board or MDF will works.
I include walls and ceiling in calculation. Floor is hard, wooden, lacquered parquet, as always.
Quote:
Originally Posted by windmillsound View Post
All I thought that diffusors could not be placed in a repeated pattern without creating all sorts of strange artifacts, but all the wall panels look identical. Can you shed some light on this please.
We use MLS to change orientation of same panels. There isn't anything strange in rooms response. At lest there is no audible or measurable artifacts...
Even without any reported problem from first designed rooms, for second room, which we described in our papers (Pressed Lizard, smaller one, with OSB diffusers, as shown at photos above), we have done different and custom diffuser design for every surface.
Old 12th February 2012
  #58
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Well, finally, there are more studios built following (more or less) MyRoom Design principles

Here is first:

Measurement results:


And second:

Measurement results:


Studios are located in Slovenia, and they aren't finished yet, so it is possible to expect better pictures in near future... heh
Rooms have volume of 32 and 45m3 before treatment,.... more info and impressions you can read in original post at their local audio forum PlanetAudio

Designer is Nenad Patkovic, a fellow acoustician who encouraged me to write and publish details about MyRoom Design principles.
Thanks Nenad!
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Old 12th February 2012
  #59
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Not sure why people are showing burst decay plots (that shows decay in periods instead of decay in milliseconds) but it would be nice to see a normal decay plot (normal time, not periods. 60 periods at 10 kHz is only 6 ms ...) in order to evaluate the decay of the space. An ETC would be even more interesting.
Old 12th February 2012
  #60
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Quote:
Originally Posted by Jens Eklund View Post
Not sure why people are showing burst decay plots (that shows decay in periods instead of decay in milliseconds)......
I ask him for this particular type of measurement results.
There may be some explaination: ARTA user manual
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