Acoustics/Treatment Reference Guide - LOOK HERE!

[Torea]

If you're looking for the quickest way to get started, I suggest checking out 1c, 2b, and 2a. These briefly and simply cover the basics (and have lots of pictures ).

This is a reference guide for basic acoustics and room treatment. Whether you're just getting started or want some touching up, this should be a good place to start. It's a big group effort and we're in the process of trying to make it easier to understand/use. Feel free to join the conversation here - Sticky with links? - And please post comments and suggestions about this reference in that thread! I'll document changes in the "Last edited" box, so you can know what's changed since you last checked.


Don't be bewildered by the amount of information here. It will take time to absorb it all, but this reference was made with the intent of making it easier to find what you want to absorb. Take it in steps and you'll learn a ton.


Enjoy


1) General Info
a) Soundproofing vs Treatment - What's the difference between soundproofing and acoustic treatment?
b) Soundproofing Myths - 7 Silly Soundproofing Myths to Avoid
c) A bit of everything - RealTraps - Acoustic Basics
d) A lot on absorption, a good read - Acoustic Treatment and Design for Recording Studios and Listening Rooms
e) Another good primer read - GIK Acoustics presents Acoustics Primer: Some Basics on Acoustics.
f) A handful of videos on acoustics - RealTraps - Videos

2) Room Set-Up/Testing
Set-up
a) An article on set-up - RealTraps - How To Set Up a Room
b) An starting place on how to orientate/place traps GIK Acoustics: Room Setup
c) Monitor set-up - Monitor Positioning. GIK Acoustics Articles and Newsletters
d) More on trap placement - RealTraps - Placing RealTraps
Testing
e) Alternative Testing Methods - RealTraps - Alternative Test Methods
f) Ethan's Mic Test - RealTraps - Measuring Microphones
g) Room EQ Wizard (REW) - REW - Room EQ Wizard Home Page
h) FuzzMeasure (FM) - FuzzMeasure Pro 3
How-Tos and Measuring Help
i) Dandan's Primer Thread - http://www.gearslutz.com/board/studi...er-v2-1-a.html
j) Ethan's Primer - RealTraps - Room Measuring Series
k) Jens' REW How-To - How to use REW
- Personally I'd say this should be its own sticky, until then, it can be here
l) Glenn's REW Video (posted in #19 below) - Measurement Tutorial

3) Absorption Info
Articles
a) Absorption part from 1b - Acoustic Treatment and Design for Recording Studios and Listening Rooms
b) Glenn's "How Bass Traps Work" - How Bass Traps Work. GIK Acoustics Articles and Newsletters.


4) Diffusion Info
Articles
a) GIK Acoustics presents "How Diffusion Works!"
b) QRD diffusers: Technical Overview

Videos
c) RealTraps - All About Diffusion


5) Early Reflections
a) What Is SBIR?, from Glenn at GIK - "What is SBIR" Acoustic Panels and Bass Traps.
b) What Are Early Reflection Points?, from Glenn at GIK - What Are Early Reflection Points. Acoustic Panels and Bass Traps.
c) Reflection Free Zone (RFZ) - RealTraps - Creating a Reflection-Free Zone


6) How-Tos/Calculators
Calculators
a) Google Sketchup, an excellent tool for creating 3D models - Google SketchUp
b) Google Sketchup Help - Google sketchup questions and trouble shooting. How can I help?
c) jhbrandt's webpage, calculators for modes, QRDs, absorption, first reflection, and more - JH Brandt - Recording Studio Design/Consulting - Publications
d) QRDude QRD calculator - QRDude: Quadratic Residue Diffuser calculator
e) Online QRD calculator for people who can't use QRDude - QRD Diffuser Well Depth Calculator
f) Skyline setup - PME Records QRD Diffusor Construction
g) Skyline Calculator - Calculate a Two-Dimensional Primitive Root Diffuser
h) Sorry, I forgot where I heard about this place, it has lots though - mh-audio.nl - AcousticCalculator
i) Porous Absorber Calculator - Porous Absorber Calculator V1.58
j) Internet Porous Absorber Calculator - Porous Absorber Calculator
k) Bob Gold's Mode Calculator - http://www.bobgolds.com/Mode/RoomModes.htm
l) RealTraps Mode Calculator - RealTraps - ModeCalc
m) Unit Conversion Calculator - Digital Dutch Converter

7) Stuff on Fiberglass
a) From Ethan on density (with measurements!) - Rigid fiberglass density tests
b) Bob Gold's Absorption Coefficients, to find similar insulation products - http://www.bobgolds.com/AbsorptionCoefficients.htm
c) For fluffy fiberglass, a quote from Andre (avare) - http://www.gearslutz.com/board/6232561-post16.html

8) Suggested Reading
a) by Rod Gervais - Home Recording Studio: Build It Like the Pros
b) by F. Alton Everest - Master Handbook of Acoustics
c) by D'Antonio/Cox - Acoustic Absorbers and Diffusers: Theory, Design and Application
d) by Philip Newell - Recording Studio Design
e) by Marshall Long - Architectural Acoustics
f) by Heinrich Kuttruff - Room Acoustics
g) A FREE publishing from the BBC (also listed in Andre's compilation) - Rose's Guide to Acoustic Practice
g) A ton of FREE writings, compiled by Andre - http://www.gearslutz.com/board/6634314-post70.html



Lastly, following the links are posts from some of the pro guys who often answer the questions in this forum. Give em a break and read the stuff they contributed to this reference, they might just end up pointing you back here anyway.

[Torea]

A few things from Ethan Winer, of RealTraps

Originally Posted by Ethan Winer

...This is a self-help forum. We will give you links to all the information you could possibly need, and then some. And when questions arise we'll gladly answer in detail. But few of the experts here have the time or energy to design your room for you, or provide one-on-one personal consulting for free. If you prefer to be handed a solution rather than spend the 5-20 hours needed to learn what's most appropriate for your specific room, you should consider hiring one of the acoustic consultants who post here often. Or rather than DIY your treatment, buy from a knowledgeable treatment vendor. Many treatment companies offer free placement advice, and often other acoustics advice, for free as part of the purchase of their products...

Originally Posted by Ethan Winer

1) Posters, PLEASE tell us the size of the room(s) you're asking for advice on. It doesn't have to be accurate to 1/4 inch, but at least within half a foot or so. American or Metric is fine.

2) Be sure to say where you are located, because the availability of acoustically useful material varies around the world. Ideally your location will be in your forum profile, so it appears every time you post as a reminder to us. Otherwise, at least state your location in your first post.

3) Please do NOT post enormous photos. Pictures should be 600-800 pixels wide at most. Viewing posts with huge photos is difficult and a nuisance.

4) Speaking of photos, the best photos are distant shots that show the entire room in context. Close-up photos are not useful. Stand outside the door if you have to. We need to see where the mix position is in the room, where your speakers are placed, what's on the side and rear walls, where the doors are, and so forth. The fewer photos needed to show all of that, the easier and faster it is for us to help you.

And from Jens Eklund

Originally Posted by Jens Eklund

1. Learn how to make measurements: REW - Room EQ Wizard Home Page
Don’t do anything without measurements.

2. Find the best position. Usually centered up against a short wall, is the best place to start. Confirm with measurements. If the room is big, you can experiment with a position away from the wall but then usually more than approx. 1,5-2 meters from it (speakers).

3. Identify and treat your modal and SBIR related issues and educate yourself about different bass-absorbing techniques.

4. Treat areas that otherwise creates early reflections.

5. If the room is big enough, add diffusers (but read up on how to use diffusers before going nuts).


Always base your decisions regarding different treatment, on measurements. Avoid thin porous only absorbers (including wall to wall –carpet, drapes etc.) unless a measurement indicates the need for it. There are many informative threads lying around; find them.

From Hannes regarding this thread

Originally Posted by Hannes_F

It would be important that reading the mentioned stickies and following the most popular suggestions will get you most probably to level 1 or 2 of the following list. The higher levels need more information and - and this is very important - individual measurements and calculations. For most people hiring a consultant will be the only way to ever get there.

Level 1 or 2 can be sufficient for the given project or not depending on the conditions and purpose. However it should be important to realistically estimate the goals and to give at least a glimpse on advanced possibilities.

1st level: Hanging absorptive panels in an existing room
Result: FR (edit: frequency response) +/- 10 to +/- 15 dB, can be optimized to +/- 8 dB at best if a measurement microphone is used for placement. Nevertheless massive modes. Lots of real world projects end up worse than +/- 8 dB.

2nd level: Hanging absorptive panels in an existing room plus installing SuperChunks
Result: FR +/- 6 dB at best, reduced modes. Lots of projects are worse than +/- 6 dB though.

3rd level: Using commercial membrane absorbers plus corner absorbers
Result: FR +/- 5 dB at best, even better reduced modes

4th level: Using closed layers of thick absorption
Result: FR +/- 4 dB at best, strongly reduced modes except the lowest, however decay on the dry side

5th level: Using closed layers of thick absorption in conjunction with reflection
Result: FR +/- 3.5 dB at best, cleaned up ITG (initial time gap) strongly reduced modes except the lowest, still on the dry side but not so bad as #4

6th level: Using tailored tuned traps, process well monitored by ETC measurements
Result: FR +/- 3 dB at best, cleaned ITG, fully controlled modes, no problem with the room being too dry

7th level and above: Integrated design using tailored tuned traps plus construction methods, soffit mounting etc.

And SAC

Originally Posted by SAC

+1 Hannes makes some very salient points.

Exuberance is great.

But it takes a bit more awareness (measurements) and knowledge in order to treat some issues (assuming one even has a defined acoustical response model in place!) than to simply install beau coup porous absorbers and an obligatory diffusor or two.

And recognizing what you don't know is as, if not more, important than simply rushing ahead with only a partial understanding and the assumption that brute force can optimally solve the issues.

This is NOT meant to discourage folks! But there is a bit more to the science of acoustics (and yes, for all the artists, it is ultimately a science) than what someone can learn by simply reading a few how to and DIY articles. No less than one can reasonably expect to buy a guitar and the right clothes and reasonably expect to become a virtuoso on the instrument in a few weeks or months (ocarina excluded!). It should be evident simply by virtue that we approach the science here to the almost complete exclusion of math, and where everything is treated as linear - just add more and the benefit increases accordingly!

And where only a few have seriously ventured to familiarize themselves with tuned resonators and diffusion. And perhaps fewer have become intimate with actually taking and using measurements. And we have only scratched the surface in this regard! Some really nice and powerful tools have become available, but they do not eliminate the fundamental need for a bit more in depth knowledge. And it is wise to recognize just how far one is willing to invest in learning this, and the limits of exactly what one knows, and to recognize when it is best to call in someone who knows just a bit more.

Folks just need to realize that while some basics are great - and an awareness of the fundamental challenges are a beginning, it is not sufficient as an end. ESPECIALLY if one fantasizes of actually building a serious studio - which ALSO necessitates a serious business plan - as witnessed by so many famous/prominent studios closing in droves around us as we speak - and the live touring business is drying up as well with the last two years seeing actual shrinkage in this sector...(oh, and with the top ten drawing acts all being over 50 years old!) (Read FOH, SCN, and other trades...)

[Torea]

BBC Documents: Lots of information here...

Library from Andre (avare)
http://www.gearslutz.com/board/6634314-post70.html

Library from PaulP
http://www.gearslutz.com/board/5217856-post1.html

[Raptor25]

Sticky!!!!

Excellent work!!

[Ihsahn1981]

Great thread!

For us used to the metric system, here is a small conversion table for some of the more common units encountered in this forum:

Inches:
1’ = 2.54 cm
2’ = 5.08 cm
4’ = 10.16 cm
6’ = 15.24 cm
24’ = 60.95 cm
32’ = 81.28 cm
42’ = 106.68 cm
48’ = 121.91 cm

Lbs (pounds):
1 lbs = 0.45 kg
2 lbs = 0.90 kg
4 lbs = 1.8 kg
6 lbs = 2.72 kg
10 lbs = 4.54 kg

[Ethan Winer]

Another small but important point: Sketchup is a great tool for planning a studio space, but not everyone has that program. If you want to show your plans for us to comment on, please post them as jpg or gif images that all browsers can display.

--Ethan

[Ethan Winer]

I don't want to bloat this thread with chit chat, but this is an important point:

Gearslutz is a public forum. This means you ask questions in public, and one or more people will reply to help you. The advantage is that everyone sees the answers and benefits, not just you. This also gives Jens fodder for links to important topics.

So please don't send PMs asking people to give you one on one personal private consulting. Most of the experts here charge for private consulting, even though they gladly pitch in publicly.

--Ethan

[Jens Eklund]

Originally Posted by Brian Cares

May i carefully suggest to add "Loudspeaker Placement" to the Sticky?

It is in there.

Originally Posted by Brian Cares

If you think, you are pretty much there, go and get the RPG Room Optimizer.

RPG Diffusor Systems

Make yourself familiar with the tool and start optimizing again.
Use the frequency based calculation and use the max number of solutions. With todays computing power you get the results in an afternoon.


If your room sounds good already, then start adding treatment!

If you plan to set up your speakers in a bomb shelter and without any treatment, then knock yourself out with "Room Optimizer"!

If however, you have a normal room and plan to treat some (high probability since you’re reading this thread); forget any simulations unless you find one that can handle boundary conditions with complex impedance (and add to this that you actually need to know the complex impedance behavior of each boundary!).


Oh, by the way; I have both “Room Optimizer” and ”Room Sizer” from RPG …



To avoid clutter in this thread, I’m replying to the below post here:

What I’m saying is that as soon as the walls are not extremely rigid and/or openings or treatment exists, any model will fail unless the model can handle complex impedance boundary conditions, but who would be able to source the data needed for each boundary unless an empty bomb shelter?

[Torea]

Not to be that guy, but

Originally Posted by torea

Please post suggestions or comments about this reference in this separate thread to keep clutter low. Thanks =)

Don't mind suggestions, I'll gladly add them in if they don't seem overly redundant. Just don't want this thread getting bogged down with extra stuff

Thanks!

[Insulation Man]

The Bob Golds' Absorption Coefficient is a really good link! Nice to see it all in once page and easy for comparison.

[Craigster]

Originally Posted by Ihsahn1981

Great thread!

For us used to the metric system, here is a small conversion table for some of the more common units encountered in this forum:

Inches:
1" = 2.54 cm
2" = 5.08 cm
4" = 10.16 cm
6" = 15.24 cm
24" = 60.95 cm
32" = 81.28 cm
42" = 106.68 cm
48" = 121.91 cm

Actually the designation of one apostrophe/single quote (') designates "foot" (i.e. 12 inches). For inches, you want the double apostrophe/double quotes ("). So, I have made the correction above.

Here, I'll reverse it for the benefit of those used to the Imperial system for translating from metric:

100 mm = 10 cm = 3.94" = approx. 1/3 foot
200 mm = 20 cm = 7.97" = approx. 2/3 foot
300 mm = 30 cm = 11.81" = approx. 1'
400 mm = 40 cm = 15.75" = approx. 1' 3 3/4"
500 mm = 50 cm = 19.685" = approx. 1' 7 2/3"

[xuandma]

this reference was made with the intent of making it easier to find what you want to absorb. Take it in steps and you'll learn a ton.

[lostprin36]

Nice post. Many thing I have learn from this.
Thanks.......





Are you looking for Music or Musician!

[College_Records]

Wavelength frequency convert lambda Hz sound conversion acoustics acoustic audio radio speed of sound and radio waves wave length light vacuum equation formula speed of light color spectrum - sengpielaudio Sengpiel Berlin

Calculator to determine the length of sound waves at all frequencies

It's helped me considering you need to affect at least 1/4 of the wavelength in order to make a difference.

[DanDan]

Before you go far down that well worn 1/4 wavelength road....
1/4 is for 100% total absorption.
For a useful difference, between 1/10 to 1/20 are common figures actually used.

See the thread Q4Avare

DD

[College_Records]

Originally Posted by DanDan

Before you go far down that well worn 1/4 wavelength road....
1/4 is for 100% total absorption.
For a useful difference, between 1/10 to 1/20 are common figures actually used.

See the thread Q4Avare

DD

Ohhhhhhhhhhhhhhhhhhhh........... I see. Still learning

[captshiznit]

Amazong thread,

Thanks OP You rock!

[moorethanart]

Fabulous thanks!

[Glenn Kuras]

Just did a video on setting up REW and taking a measurement. Let me know if you want it in the list or just keep it here.

REW: Room EQ Wizard Room Measurement Tutorial - YouTube

[akebrake]

Originally Posted by Glenn Kuras

Just did a video on setting up REW and taking a measurement. Let me know if you want it in the list or just keep it here.

REW: Room EQ Wizard Room Measurement Tutorial - YouTube

Excellent initiative Glenn! REW isn't simple to use for the newbie (but an extremely competent program! )

This video is a great help how to start start. Go on, measure with it!


What do I think? (of the video)

It's a little bit fast to follow. But of course you can stop it, rewind and think.

Fade down the (terrible) backing music now and then

Other wise...

The video is GREAT!

If I want it in the list? Sorry I don't understand the question.

It belongs to a sticker I think, for those who want to learn

Cheers

[Glenn Kuras]

It's a little bit fast to follow. But of course you can stop it, rewind and think.

My fault, when I went over the content with my staff I wanted all of that in the video and told them under 10 min.

Fade down the (terrible) backing music now and then

Not my pick. Sometimes you have to go with the flow.

[Torea]

Ok, it's added. Didn't get a chance to watch it (actually on vacation in Atlanta right now!) but I trust you got it right I think all the help for properly using REW is great to have, Jens' and DanDan's tutorial's are great, but it's also nice to have something visual.


I don't check GS as often anymore but I do make an effort to check this page and also the page where we started the conversation. I definitely don't mind putting more stuff in here, just as long as it's not overly redundant (something need to be covered in different ways) or otherwise unfitting to be put in. But I'm not exactly the best person to make that decision, especially with all the pros hanging out here. So feel free to toss stuff around in the other thread, just let me know when something should be added.

[btbam513]

how do these graphs look? this is my vocal booth. I think the decay time is good, but i am trying to figure out how to smooth out all those valleys