Acoustics/Treatment Reference Guide - LOOK HERE!

^^^ Excellent, now how do we make this a sticky? And not just "a" sticky, but the first sticky at the top of the list. (No offense to other sticky authors... heh)

Jay?

--Ethan

You may want to add these on SBIR and early reflection points. The question does seem to come up a lot on here.
GIK Acoustics. Acoustic Panels and Bass Traps.
GIK Acoustics. Acoustic Panels and Bass Traps.

Found this:

"Generally, you're best off if the distance from speaker face to front wall, driver centers to side wall, and driver center to floor are 3 different dimensions in order to not reinforce any specific set of harmonics by having all the boundaries generate the same SBIR effect."

Reminding me of this thread (starting on topic at post 21):

Corner bass traps blocked by speakers

heh

Thanks! I think I'll make a separate section for Early Reflections so they're easier to find.

Any posts I missed on absorption and/or early reflections? Those sections seem a little flimsy, even though "bass traps galore" seems to be a popular motto here

I reported it and kindly asked for it to be stickied

Dunno how to get it moved up though, you might have to start a petition haha

Didn't notice the development thread, thanks John. Perhaps it should have been left develop for some time before Sticking it. It will now require unsticking to add things. Be careful what we wish for.

If it does get unstuck and added to, may I recommend two prime sources.
The BBC docs and Recording Studio Design by Newell.
Also.
A cross platform Porous Absorber Calculator which includes Random Incidence
Porous Absorber Calculator - Results
johnlsayers.com studiotips.com, Auralex RPG Genelec and Harman sites.

DD

It's not locked, so we can still add and edit. I've been tweaking it a bit since it was posted.

Maybe someone can make a zip file or a link to all the BBC docs (unless that causes some legal issue), that way they're all in one, easy to reference place?

Thanks for the tip on the book and the calculator. I'll throw em in

K, DD I added your suggestions.

Also, when I add stuff, I'll try to remember to note where and why in the "reason edited" box. That way, it's easier to see the new stuff =)

If you are new to studio design, or want a marvelous series of articles in plain language about studio design to review, there are severtal great fantastic articles by Malcoml Chisholm located here.

The (great) BBC RD Reports from are here. http://downloads.bbc.co.uk/rd/pubs/r...60s_70to96.pdf

Rose's very highly recommended Guide to Acoustic Practice is here. http://www.bbc.co.uk/rd/pubs/archive...icpractice.pdf

BBC Engineering docs are here. http://www.bbc.co.uk/rd/pubs/archive...hs_listing.pdf

BBC Engineering Monographs are here. http://www.bbc.co.uk/rd/pubs/archive...hs_listing.pdf

BBC tests of studio partitions for transmission loss are here. http://www.bbc.co.uk/rd/pubs/archive...partitions.pdf

EBU Tech 3276 is a practical guide for acoustic performance of control rooms. It is not for a "world class" room, but no one would say a room meeting it is bad, or even as low as average.

http://tech.ebu.ch/docs/tech/tech3276.pdf

A similar set of documents from the ITU are:

ITU-R-BS775-1, and
ITU-R-BS1116-1.

A marvelous document and quite readable that in addition to technical recommendations includes a history of multi-channel sound and details the many types of environments it is used in is the NARAS P&E Wing Recommendations for Surround Sound Production
http://www2.grammy.com/EDCB9D23-0365...mendations.pdf

Quite comprehensive as a collection of surround sound control room recommendations is the AES TD 1001 Multichannel Surround Ssytems and Operations

http://www.aes.org/technical/documents/AESTD1001.pdf

Many of the standards listed above are interrelated related. With teutonichic precision the Tonmeister Surround Sound Forum (also known as the Tonmeister SSF, or just SSF) is about the most comprehensive of all of them.

http://www.tonmeister.de/foren/surro...E_2002_v2a.PDF


For "regular" gypsum board based walls, over 350 variations tested are in the NRC IR 761. http://www.nrc-cnrc.gc.ca/obj/irc/do...r761/ir761.pdf. Similar data for concrete block walls are in IR 586. http://www.nrc-cnrc.gc.ca/obj/irc/do...r586/ir586.pdf. Focused on stud type walls with lots of great construction detail, but only STC values is Residential Steel Framing. I strongly urge studying IR761 and IR586 first to understand MAM resonance before using this for studio wall design.

A field that has little data available for us is HVAC. The McQuay HVAC Acoustic Fundamentals Application Guide is a rare exception.


A treasure trove of acoustic information too often overlooked is in the JBL Professional Sound System Design Manual, initially written by George Augsburger, and revised by John Eargle, here, in 2 parts:
JBL :: Technical Library and JBL :: Technical Library


Sometimes we use leading edge sources for the information that we gather. A great example is this NASA document for low frequency absorption data. An Analysis of Sound Absorbing Linings for the Interior of the NASA Ames 80x120-foot Wind Tunnel
NASA also has very large reverberation chambers. Here is a paper on the one at the Glenn Research Center 227390d1301337909 nasa

There are other times when very different ideas are investigated. Here is a paper on absorbers inspired by mattresses. Variable Low-Frequency Absorber for Multi Purpose Concert Halls


An excellent practical guide for vibration and sound isolation is the US Military UFC (United Facilities Criteria) 3-450-01. http://www.wbdg.org/ccb/DOD/UFC/ufc_3_450_01.pdf. Some of the documents we can get are undergraduate level acoustics books. One such book is the ] Fläkt Woods Practical Guide to Noise Control.

A great document geared (a bit) more to the amateur is the Bradford Acoustic Insulation Design Guide Thanks to Seb for finding this one and DanDan for pointing it out. http://www.bradfordinsulation.com.au...06bffb3269.PDF

A great acoustics document from a field that is totally unexpected is from the Rockwool Marine and Offshore. It is like an acoustics course in and of itself. http://www.rockwool.it/files/RW-IT/f..._vers3_web.pdf

It is useful to compare what is involved in determing sound isolation requirements in other fields. The following deals with shooting range sound isolation requirements. Note that other than the sound source, the method is identical to what is described here on Gearslutz! Shooting Range Sound


Just about everything has some form of absorption and or diffusion. This one is about snow. Sound Abosorption of Snow

A key thing about all of the above documents is that they are first class professional writings AND FREE.

Freely,
Andre

Good, that must be a new Sticky feature. I had to get mine unstuck, thus the V2.1 to indicate that it was changed. In your case I would just keep adding in some well chosen faves. Andre's library is tops.
Spoilt for choice now but PaulP did select his favourite BBC's and collected them.
BBC documents

DD

Thank you for the complement. PaulP's selection of RD Reports is fantastic. It is hard to know where to start chosing what to suggest in them. Want a detailed report (3 actually) on a control room design that seemed great in theory but fell apart in practice? Want to know the results of recording in an anechoic chamber? Want a good sound recording with an underwater diver's helmet? They are all in the RD Reports. Want a design report on the BBC/Coles ribbon microphone? There is an Engineering Monograph on that.

As Eris Desart once remarked, the BBC RD budget is the same size as that of small countries. We have the benefit of the BBC sharing them with us for free!

Hail Britannia!

Maybe a bit British,
Andre

Well the Queen is coming to my hometown Cork very soon.
Apparently there was a bidding war for the Photo rights, Hello Mag, OK, all of them. Finally An Phoblacht, (staunchly ********** to say the least) won the bidding. All they wanted was one clear shot......

DD

Wow! Andre, where were you and that list when this all started? haha. I think I'll just link to your post (and PaulP's).



Yeah, definitely don't wanna just throw everything and anything in there, but if it can help and(/or) be easily understood, it'd be nice to have. Gonna become a problem to manage after a while, but hopefully it'll stay sort-of neat and tidy.

It started years ago. The is partial. Two of the gems I am to have come across are ROSE and the UFC document. Amazing under-known. If under-known is a word.

The hardest part is deciding what and how to group all the documents.

If you feel it worthwhile, all the papers on Leo Beranek's papers page are a goldmine on concert hall and opera house acoustics.

I f people are interested in the life of Beranek, here is an interview with him

Under recommended readng please add Long, Architectural Acoustics and Kuttruff, Acoustics. Long is a standard for the subject, and Kuttruff is the same on graduate level.

And you thought it would get easier selecting and sorting...

Not sadistically on purpose,
Andre

There is a kind of minimal sticky policy on GS, which I (strangely perhaps) fully agree with. But now that you have achieved this Torea, with much approval from many who I respect, I now fully support your venture. That is why I have been quiet.
Personally if I have a question which is of great interest to me, I have a little bunch of friends here who I ask publicly or privately as appropriate.
Again, Andre's library is the motherlode.
So as we are at it.
Thomas Barefoot's 2D Wall Bounce Calculator. Can't find a decent straight download so I put a link to it on my site. Acoustic Resources « Irish Acoustics
There is also a really useful and accurate link to a Hearing Test there.
I will, when I get around to it, add other resources there, Andre's take on Gas Flow Resistivity and Lupos Master of ETC articles. Both pending....
Lastly for now. ModeWiz is brilliant. Acoustics Forum • View topic - modeWizard: Yet Another Mode Calculator but with a twist
And a free eBook. http://www.santafevisions.com/csf/ht...f_contents.htm
All good, DD

+1 and the acoustics course is fantastic!

Andre

Some more links and docs to consider including on your master post/page.

EBU Tech 3276 is a practical guide for acoustic performance of control rooms. As I happened to write earlier today, it is not for a "world class" room, but no one would say a room meeting it is bad, or even as low as average.

http://tech.ebu.ch/docs/tech/tech3276.pdf

A marvelous document and quite readable that in addition to technical recommendations includes a history of multi-channel sound and details the many types of environments it is used in is the NARAS P&E Wing Recommendations for Surround Sound Production
http://www2.grammy.com/EDCB9D23-0365...mendations.pdf

Quite comprehensive as a collection of surround sound control room recommendations is the AES TD 1001 Multichannel Surround Ssytems and Operations

http://www.aes.org/technical/documents/AESTD1001.pdf

Andre

I ran into this post while thinking and was reminded by email of ITU. 2 documents of interest to us gearsluters are ITU 775 and 1116.

Andre

I have reconsidered and done a further U turn on the value or not of this Sticky. I believe the idea is a victim of it's own success and lacks focus. Sorry Torea. I now see people quoting this Sticky in answer to basically any question. Some of the OP's read through hours of it and come back unanswered.
If it is intended for beginners it has far too much in it, and much of it is way too high brow. Cox and D'Antonio on the coffee table?
If it is intended for avid learners, again too much and at a very varied level, from beginners How-to's to White Papers.
Furthermore most people, including myself, did not initially notice this development thread, which is a really clever way to keep the Sticky clean.
Didn't work, and some babies went out with the bathwater.
To rescue one baby, Brian Cares made the point that speaker and listener placement is a hugely over-ridingly powerful tool.
I have seen Bob Hodas call it 70% of the job.

DD

I think the problem is that some want the easy answers served on a silver plate. The sticky thread is as close to this you’ll get. If shorter and “simpler”, the risk of creating new 38% rules increases dramatically! I personally think there’s a lot of things’ missing but who has the time of compiling all that should be included.

You guys both know your onions.... Perhaps I can give a view from a "learner"..... So, based on the last two posts from Jens and Dan.......

A few years back I turned a very small spare bedroom into a very small studio/CR. I scoured forums and internet sites to form a basic understanding of what issues there are in small room acoustics, and the ways to treat them, etc. etc. By the end of the process I felt good about what I had learnt and achieved. At that time, I only dipped into the GS forum.

Then I moved house and at the beginning of this year I started the process again on a slightly bigger room. I had previously made "movable" treatment knowing that I would be moving over the next few years. But, with the new room being bigger, I wanted to add to the arsenal.

As I delved deeper into acoustics (especially here on GS) I started to realise that a lot of what I had learnt and come to understand was in fact not necessarily correct. There were "givens" on some sites and in some forums that were challenged and even ridiculed here. A few examples:

- the 38% "rule"
- more density = better bass trap
- superchunks and absorptive reflection panels = the answer....

Many others which don't spring to mind right now but which I can add if needed.

So for a while after these revelations I felt there was a real need for a sticky which directed readers to understand that some of the basic information available for home studios is in fact a turn down a blind alley. And it was good timing too..... because a few months ago there were several long threads from people in my exact same position. They had read and summised that superchunks and panels were the way forward, treated accordingly...... but then did not achieve the results they had hoped for. Many agreed that it was sad to see people (myself included) waste time and money on ineffective solutions.

So why my ramblings?

I think the sticky should start with a highlighting of some of the things mentioned above (and others)..... "myths" if you like, which should not be followed and which should be dispelled from the outset.

I then think the sticky needs to highlight the difference between the easy way and the hard way. Perhaps it can even be split into Easy and Hard sections, or Basic and Advanced or what ever.

An explanation at the start could serve to highlight why there is a need for a difference. IE - the easy way will most likely not end in the best results, but it will be less risky, easy to implement, cheaper, quicker, etc. etc. and does not rely on a good and deep understanding of the principles involved. OTOH, the Hard route will require more learning and understanding (of the principles involved, difference types of treatment, and how to make them and use them), it will be more time consuming, it may involves risks (i.e. pressure traps which may not work, etc.), will most likely end up costing more - definitely in time if not money. Of course, the return is likely to be a better sounding room.

If set out like this, the sticky will serve an important purpose in my eyes - dispelling internet myths/crap from the outset! It will also help address the silver platter syndrome, and make it clear that the "answer" is not simple. It can be made simpler, but results will most likely suffer as a consequence of simplifying the process. Or.... people have to accept that for good results there are no clear answers, but at least the sticky can then go on to provide a whole host of further reading for the folk who want to get the hands and brains dirty.

What do people think? Am I talking stupid? Or does this make sense? If the latter...... I'll be hanging around in this forum for some time to come I would imagine, and I would therefore be happy to give some time and help toward improving the sticky further, reshaping it, and adding further links as necessary.....

Or I could always just get my coat....

Cheers

Max

+1, more or less. heh

HAHA - what, as in +0.80?

Someone wants to improve their room. What to do?
Hire a Pro.....too expensive (is it really or is this a myth?)
Buy commercial products and get a room treatment plan included for free.
DIY based on generalised advise on websites, in tandem with questioning of that advice here.

Then the tabloid posters start calling some very sound starting points as myths. Even websites have whole sections exposing 'myths'.

Let me start a few more.

Acoustic treatment is cheap and simple.
Even a small amount of it yields amazing sonic benefits.
Everyone can and should do it at it's most basic.
The benefits will encourage many to take this further.

How about we just publish our bookmarks here. Let those with the time find the ones that keep cropping up in lists from respected posters.

We would end up with a great library of bookmarks.

Not a place to send newbies though. You can't have this both ways at once.

DD

DD

I deleted my posts from the sticky.

I still find it very important to point out the importance of speaker placement.

I´ve been working on my room for the past two years. I tried the usual recommendations and positions but did not go too far with placement. Instead i started with broadband absorbtion. Added more broadband absorbtion. Then i went with tunable helmholtz devices. I spent more than 2k on acoustic stuff (due to my really bad building skills).

I then invited the guy who built my speakers to check out my room and hear what his speakers sound like and he was just: "Nope. Try again!"

He advised me on a routine which worked wonders for me. Its really simple and you probably know it. But sometimes you dont see the forest for the trees...

So i started again, following his routine. Which goes:

- Listen to your speakers in the freefield to hear what they really sound like!

- Start in an empty room. With one speaker. Try to find the best sounding placement. Dont be afraid of trying unusual/unsuspected positions.

- If you think it sounds good, try again.

- Listen.

- Listen again!

- Then add the second speaker and listen.

- Move things around. Start with rather big changes. Try to get closer to the ideal.

- If you think you´re there..

- Listen.

- Move the speakers again.

- And again..

- This process might last weeks/months.

- Then, measure. (Measuring later in the process gives you the ability to learn your rooms response intimately.)

- If you think you´re there, use stuff like the RPG Room Optimizer or CaraCalc. (In the end its physics. And i suspect that most folks looking for advice do work in residential cubic rooms.)

- The software will suggest different placements. Try them. Mark them. You will be amazed by the effect of moving the speakers just a tiny little bit. (I got rid of a couple really nasty nulls and peaks around 45 dB. The whole spectrum got "flat" within 20 dB rather than 60 dB..)

- Every room has its sweetspot!

- If you think you cant get it any better, start adding treatment and adress the problems which are (of course!) still apparent.


After changing the placement, my room sounded better without all the treatment than it sounded with the bad positions and treatment worth 2k. When i then started to add the treatment the room started to sing...


I looked around in the forum. And there were tons of threads (the 80Hz null thread comes to my mind) where people discussed gas flow resistances, membrane stuff and minutae. But noone suggested to try different positions for the speakers. And to my believe (and founded on my experiences) this is the utmost important part of the game which is practically totally ignored here.

Yeah well, theres Glens little advise on placement. But its kind of hidden und buried amongst all that other stuff which makes probably only 30-40 percent of the whole picture. The placement issue should (imvho) be the very first thing to point people at. Having this information earlier in the process would have saved me serious headaches and tons of money spent. (But i understand that this is probably not in the interest of some participants here..)

Edit:

Regarding the software: If you dont have the time to experiment, by all means, use the software from the beginning. The learning effect wont be that effective but you get results rather fast. Use frequency based calculation and the max number of solutions. With todays computing power you should get results in an afternoon. I´m still amazed by the fact that this software is 14 years old but it still does work wonders for the small homestudio.
CaraCalc is even more amazing. You can enter data different from cubic rooms. You can also define furniture, mixing desks, everything one probably has in its studio. You even can incorporate your speakers data. (Theres a growing databse on the Elac website too.) Its a bit more complicated and it its intended use is more aimed at the HiFi/Sourround market. But not everything what is good for HiFi must be bad for studio. The animated 3d display of how the waveforms break up in the room really give you a different view on your environment. You can basically see what happening in your room and act accordingly..

Interesting stuff which - as we now know - goes hand in hand with Bob Hodas's "70%" in the Dave Pensando video:

vid: Dave Pensado's Place: #21-Secrets behind tuning your room.

But as someone who is still learning, I'd love to hear more about this point..... It surprises me that tiny speaker movement could have such an effect at such a low frequency.....

The way I understand it (which could be wrong.....) moving the speakers is not likely to have a dramatic effect on modes, at least not when moved in tiny amounts. And nor would SBIR be effected. Perhaps the frequency(s) might change, but again - huge amount of effect in and around 45Hz?

Without doubt.
DD

I just posted this on the other thread:

Note that I agree with what Brian Cares said but don't want to start a number that might be twisted over time.

Great sticky Torea!

Looking over the main post in light of the latest discussions about Bob Hodas' video, I suggest that 2c and 2b be switched? This gives a logical order to the section 2.

BTW, have I told you great sticky?

Andre