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MyRoom Acoustic Design
Old 6th January 2016
  #151
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Quote:
Originally Posted by boggy View Post
I never spend more than 2.5' thickness of treatment, diffusers including... but I didn't do large rooms
Roughly, what is the largest room you've applied this design to? Have you found a strong correlation between the ETC (initial diffuse level and decay slope) and room size?

The space I'm in now still has to have the potential to function residentially on occasion, so the treatment plan is fairly typical corner and first reflection trapping. I'd really like to apply the MyRoom design to a mix suite and am trying to build a loose set of sizing criteria to assess potential commercial spaces.

I'm also curious how(if) your air transparent diffusor design has evolved.
Specifically thinking about the effectiveness and predictability of the diffusion as well as controlling the transition zone between absorption and diffusion.

Switching from professional mixer to very amateur acoustician: I've been toying around with the idea of a 2D diffusor made of fiber-filled square tubing with holes in the end-caps.

Thanks again for your time and all the information you've shared.

-Jim

Last edited by soundthinker; 6th January 2016 at 11:46 PM.. Reason: Changed last two lines
Old 7th January 2016
  #152
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Quote:
Originally Posted by soundthinker View Post
Roughly, what is the largest room you've applied this design to? Have you found a strong correlation between the ETC (initial diffuse level and decay slope) and room size?
Well, I'm nearly at the end of construction of first ever Control Room built following new MyRoom Mk2 principle, so yes, it is the biggest!
Without joking, this one has recommended room height, just noted in our conversation, but length and width are still bedroom size, with floor surface size (without treatment) of 22m2 (237ft2).
After first final measurements, I noticed an increase in room decay time, more stable T(30) through whole frequency range, compared to my usual designs of rooms with similar volume.

EDIT: I forget the link, this is the studio project construction shown in gearslutz tread:
https://www.gearslutz.com/board/11016381-post2.html

Quote:
Originally Posted by soundthinker View Post
The space I'm in now still has to have the potential to function residentially on occasion, so the treatment plan is fairly typical corner and first reflection trapping. I'd really like to apply the MyRoom design to a mix suite and am trying to build a loose set of sizing criteria to assess potential commercial spaces.
Good to hear.
MyRoom Design was initially invented for smaller surround control room, and I never experience a better way to treat the residential size of the rooms, where you can successfully control both low frequency stability and more liveliness in the room, without diffuse, not specular reflections.
Quote:
Originally Posted by soundthinker View Post
I'm also curious how(if) your air transparent diffusor design has evolved.
Specifically thinking about the effectiveness and predictability of the diffusion as well as controlling the transition zone between absorption and diffusion.
Well, air transparent diffuser is extremely important for whole (bigger!) picture, because it defines the room diffuse field, main price of the room acoustic building, low end absorption, ... So... Diffusion is just part of the story, if someone goes to real building and try to make things better, air transparent diffuser improvement define success of the whole project, including decreasing price of the building.

EDIT: I plan to write paper about development of MyRoom Design, compared to first introduction, for an AES convention in Paris this year. So, more will be later about this topic
Quote:
Originally Posted by soundthinker View Post
Switching from professional mixer to very amateur acoustician: I've been toying around with the idea of a 2D diffusor made of fiber-filled square tubing with holes in the end-caps.
Curiously, something as that, was planned for second room in Novi Sad 2006-7, when first ever MyRoom Design was introduced... It was never built, because tight timing...
Quote:
Originally Posted by soundthinker View Post
Thanks again for your time and all the information you've shared.

-Jim
My pleasure.




Last edited by boggy; 7th January 2016 at 03:59 AM..
Old 7th January 2016
  #153
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Quote:
Originally Posted by boggy View Post
After first final measurements, I noticed an increase in room decay time, more stable T(30) through whole frequency range, compared to my usual designs of rooms with similar volume.
...
this is the studio project construction...
I was following that thread. Looking forward to seeing the completed studio. What do you think contributed to the increased decay?
Quote:
I plan to write paper about development of MyRoom Design, compared to first introduction, for an AES convention in Paris this year. So, more will be later about this topic
That's one paper I'll certainly be buying from AES. Sorry I won't be in Paris to see it presented.
Quote:
Curiously, something as that, was planned for second room in Novi Sad 2006-7, when first ever MyRoom Design was introduced...
Currently spinning my wheels pondering optimal hole sizing and spacing. Probably at the point where I should just make up a number of different end-caps and do some rudimentary testing.

-Jim
Old 7th January 2016
  #154
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Quote:
Originally Posted by soundthinker View Post
I was following that thread. Looking forward to seeing the completed studio. What do you think contributed to the increased decay?
I deliberately decreased the gap between slats, so it is expected.
Decay time is measured about 200ms, and very coherent.
Quote:
Originally Posted by soundthinker View Post
That's one paper I'll certainly be buying from AES. Sorry I won't be in Paris to see it presented.
Thanks, I will be glad.
Quote:
Originally Posted by soundthinker View Post
Currently spinning my wheels pondering optimal hole sizing and spacing. Probably at the point where I should just make up a number of different end-caps and do some rudimentary testing.

-Jim
I was thinking about using PVC tubes for plumbing, they may be cheap and strong.




-BP
Old 7th January 2016
  #155
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Quote:
Originally Posted by boggy View Post
…..I was thinking about using PVC tubes for plumbing, they may be cheap and strong.




-BP
+1

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Old 7th January 2016
  #156
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Here are preliminary measurement results of T30 from Control Room in M2932 Studio:








-BP
Old 8th January 2016
  #157
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Thanks for sharing the T30 measurement.

That leads me to a broader, off-topic question. Assuming you are looking for a consistent decay over as much of the frequency spectrum as possible, would a good strategy be to:

1. treat the low-end as much as is reasonable first
2. measure the decay at ~100-200Hz (where the AES RT60 recommendation flattens out)
3. use that decay as the target for the mid-high spectrum?

In other words, I'm looking for a way to determine the 'best reasonable' decay that I should aim for in the context of a room with space and construction limitations. If I can only get my LF decay to 300ms, does it make sense to work to make the mid-high decay any shorter than that?

Not sure if this question make sense...


Quote:
I was thinking about using PVC tubes for plumbing, they may be cheap and strong
I thought about that in two ways:

1. Cut the tubes to the different QRD/PRD lengths and plug the ends
2. Cut the tubes to the same length and use them as the 'fins' of the diffuser with circular plugs inserted to different depths.

Either way the space between the stacked tubes acts as the pass-through to the absorption behind. The first option might offer more scattering from the sides of the tubes, but the second option seems more predictable.

-Jim
Old 8th January 2016
  #158
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Quote:
Originally Posted by soundthinker View Post
Thanks for sharing the T30 measurement.

That leads me to a broader, off-topic question. Assuming you are looking for a consistent decay over as much of the frequency spectrum as possible, would a good strategy be to:

1. treat the low-end as much as is reasonable first
2. measure the decay at ~100-200Hz (where the AES RT60 recommendation flattens out)
3. use that decay as the target for the mid-high spectrum?
Well, I cannot be that impatient. Measurements are tricky business... If you don't precisely know what you measure and why you measure, results may drive you to the wrong conclusion in musical acoustics, especially.

You can increase decay without diffusers. There are many ways... More cheap... But higher decay only, can't guarantee that you will get an excellent control room. Empty, untreated room already has high decay too.

I was patient with this decay process, during the years, because I primarily respect people's subjective impressions than strictly my measurements. I use measurements to increase people's positive subjective impressions, but not measurement results itself.
What I actually know, from my experience, that is only serious and quality bass room treatment drive all people to the very excited positive expression... all after that still may be a taste and personal preference, or topic for the debate, in other words.
Quote:
Originally Posted by soundthinker View Post
In other words, I'm looking for a way to determine the 'best reasonable' decay that I should aim for in the context of a room with space and construction limitations. If I can only get my LF decay to 300ms, does it make sense to work to make the mid-high decay any shorter than that?

Not sure if this question make sense...
Well, I'm not the guy able enough or brave enough to qualify whole room treatment from only bare measurement results, except for Frequency Response flatness below 200Hz, I noted that earlier
There is no reason to expect in every room decay of 300ms, if we have a Sabine equation in mind, where reverberation is volume dependent. Only what I want is to reach the upper limit from the recommendations:

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”, ITU-R Recommendation BS.1116 (rev. 3), ITU, Geneva, 2015.
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

Quote:
Originally Posted by soundthinker View Post


I thought about that in two ways:

1. Cut the tubes to the different QRD/PRD lengths and plug the ends
2. Cut the tubes to the same length and use them as the 'fins' of the diffuser with circular plugs inserted to different depths.

Either way the space between the stacked tubes acts as the pass-through to the absorption behind. The first option might offer more scattering from the sides of the tubes, but the second option seems more predictable.

-Jim
This looks similar to a bunch of bass reflex tubes ... Good luck!





-BP

Last edited by boggy; 8th January 2016 at 12:12 PM..
Old 8th January 2016
  #159
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Quote:
Originally Posted by soundthinker View Post
…..I thought about that in two ways:

1. Cut the tubes to the different QRD/PRD lengths and plug the ends
2. Cut the tubes to the same length and use them as the 'fins' of the diffuser with circular plugs inserted to different depths..-Jim
(I am not Boggy)
You can read about construction of a BBC prototype diffuser using plastic material here.
http://downloads.bbc.co.uk/rd/pubs/reports/1995-01.pdf
Old 11th January 2016
  #160
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Quote:
Originally Posted by boggy View Post
Measurements are tricky business... If you don't precisely know what you measure and why you measure, results may drive you to the wrong conclusion in musical acoustics, especially.
...
only serious and quality bass room treatment drive all people to the very excited positive expression... all after that still may be a taste and personal preference, or topic for the debate, in other words.

Well, I'm not the guy able enough or brave enough to qualify whole room treatment from only bare measurement results, except for Frequency Response flatness below 200Hz, I noted that earlier
...
-BP
Thanks to you and akebrake for the links.

I'm very much in agreement with the holistic, no one treatment fits all approach advocated here.

More off-topic musings: There is plenty of information on gs about specific room treatments and some general guidance about picking a room model, treating the low end, and adjusting the response from there as the room is built. I'm curious how often and how much a room's design changes during a professional build? andre's signature about 90% design makes me wonder how much detail I should try to figure out on paper before doing any construction and how much I should expect to measure and build incrementally.

There is a build here by G.E.(IIRC) where he planned a rise around 1kHz when the room was empty in anticipation of the response changing when full of musicians. How close do the pros get when estimating the treatment needed to get a particular response?

-Jim

EDIT: By design changes, I'm mostly referring to types, placement, and amount of acoustic treatment, not changes in the targeted room model.

Last edited by soundthinker; 12th January 2016 at 02:54 AM.. Reason: Clarification, and spelling
Old 11th January 2016
  #161
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Quote:
Originally Posted by soundthinker View Post
andre's signature about 90% design makes me wonder how much detail I should try to figure out on paper before doing any construction and how much I should expect to measure and build incrementally.

EDIT: By design changes, I'm mostly referring to types, placement, and amount of acoustic treatment, not changes in the targeted room model.
It is fairly easy to tell people who have not spent enough time in the design phase as an empirical relationship evolves of spending 3 times as much as they planned.

There can be a fair amount of tuning with tuned acoustic treatments, but I have relatively little, as in I do not recall ever, work where I has to make adjustments to the quantity or type. Placement has had some adjustment for listening area.

On budget,
Andre
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Old 13th January 2016
  #162
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Recalculations

Quote:
Originally Posted by soundthinker View Post
... There is a build here by G.E.(IIRC) where he planned a rise around 1kHz when the room was empty in anticipation of the response changing when full of musicians. How close do the pros get when estimating the treatment needed to get a particular response? ... By design changes, I'm mostly referring to types, placement, and amount of , not changes in the targeted room model.
I think you're recalling the image (dusty screenshot, empty room before and after treatment) below from a quite large rehearsal room. With a project like this you simply have to meet the civil engineers target (which basically was 600ms ±200ms). The larger the room the more developed the sound field is the better Sabine calculations work. I could have changed the number/type of modules (~120 in this room) to reach the target but there was no need.
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MyRoom Acoustic Design-t30.jpg  
Old 7th April 2016
  #163
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Hello everybody,

Quote:
Originally Posted by boggy View Post
..........
EDIT: I plan to write paper about development of MyRoom Design, compared to first introduction, for an AES convention in Paris this year. So, more will be later about this topic ......
Well, paper is accepted from AESorg, and will be presented at Convention in Paris, June 4 - 7, 2016.

I think this is a good moment to continue the discussion in a new thread, and lock this old.
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