# Acoustic Room Treatment for New Studio - What am I doing?



## NathanTiemeyer (Mar 11, 2017)

Hey all!

I've been reading up lately here and several other places on what to do and what not to do when it comes to acoustic treatment.

My room is a square, a 12 ft by 10 ft old bedroom which is soon becoming my new studio.





I work almost exclusively with virtual instruments and only record some voice over occasionally, so the treatment would be for mixing.

My monitors are a pair of JBL LSR 308's (which I'm loving btw  ) In case that helps!

Do I really need to invest a fortune into a room that was never destined to be a studio in the first place? 

At first I thought I'd go the acoustic foam route- apparently it's "useless."
So I looked at panels, GIK's products looked great but they were just out of my price range.
Then I saw some panels and bass traps from ATS and they seem to be just what I'm looking for.


I think it'd be a good idea to start out with:
2 x ATS Acoustic Panel - 24 x 48 x 2
and
2 x ATS Acoustic Bass Trap - 24 x 48 x 4-
... The panels to be placed on the sides of the room, and the bass traps to be placed in the front corners.

Will these efforts really make that much of a difference, especially considering the square room I'm working with?

Should I consult a professional before I purchase any of this?

What do you guys think of this idea?

Anyone else working in a similar situation?

Thanks in advance for the help


----------



## ryanstrong (Mar 11, 2017)

I am not an acoustician nor do I have a great understanding of acoustics so I will just RELAY what my "acoustic guy" told me I needed to do with a similar setup but he HIGHLY suggested putting "monster" bass traps immediately behind you more then any other spots as a starting point.


----------



## Gerhard Westphalen (Mar 11, 2017)

I'd start by taking some measurements. If you don't have a measurement mic (the cheap $60 Behringer one is fine) use another mic that has a flat frequency response in the low end. All we're looking at is the low end (starting below around 300Hz). This will determine how much of a problem you have. If you don't have the low end controlled then anything else you do won't really help very much.

An absorption panel on the corners won't do all that much. If you have problems in the bass you need real bass traps like membrane, diaphragmatic, or Helmoltz technologies. The GIK seem to be some of the cheapest options. You could contact them to get their treatment suggestion.

For treating the higher frequencies I'd go with 4" panels (or thinner panels spaced 4" from the wall). If you don't do this then you won't attenuate everything and get partial reflections which is worse than getting the full frequency reflection.

I believe that treating the front and back wall reflections as well as the ceiling is more important than the lateral reflections so I'd start there. As long as you're not getting flutter echo at the listening position, treating the lateral reflections isn't necessary and more of a personal choice.

If you have access to tools then I'd suggest building your own 4" panels and investing the rest into bass treatment.

Regardless of what you do, I'd suggest factoring Reference 3 into your budget.


----------



## Nick Batzdorf (Mar 11, 2017)

The bass traps are likely to be a good idea. But those acoustic panels will knock down high frequencies. I'd wait to see whether that's what you need, and if do then I'd place them anywhere other than where you have them.


----------



## chillbot (Mar 11, 2017)

Nick Batzdorf said:


> The bass traps are likely to be a good idea. But those acoustic panels will knock down high frequencies. I'd wait to see whether that's what you need, and if do then I'd place them anywhere other than where you have them.


Whatever, Nick.

I have a lot of expertise in this area here is a rough sketch of what you want to be doing.


----------



## Nick Batzdorf (Mar 11, 2017)

Great design, chillbot. Love it.


----------



## synthpunk (Mar 12, 2017)

Or you could spend 10k and get Attack Wall.
http://www.asc-studio-acoustics.com/products/attack-wall/


----------



## gsilbers (Mar 12, 2017)

synthpunk said:


> Or you could get Attack Wall.
> http://www.asc-studio-acoustics.com/products/attack-wall/



that thing was amazing!!! i checked it out at AES and ocudnt believe. 
but pricey


----------



## gsilbers (Mar 12, 2017)

NathanTiemeyer said:


> Hey all!
> 
> I've been reading up lately here and several other places on what to do and what not to do when it comes to acoustic treatment.
> 
> ...




This opinion will be a little far out and crazy for some...

but you can buy the sound treatment panels in ebays stores for a fraction of the price of GIK and auralex products. you would think its lower quality etc. but when you start to read about those stores, its normal foam companies who just copied the design and material from those acustic brands who need to pay for marketing and shelf space at GC.
you read the absorvency and other acoustic measurements and they are about the same. ITs not rocket sciene or anything complicated and if you have a foam store, why not release acoustic products?
there is a company around there thats two ex auralex guys who sell fro their ebaystore. forgot the name. I got a chance to get a auralex panel and one from those stores and didnt hear a diference. the gearslutz forum is filled with snobs in this dept so watch out. they are also sales poepple there posting. 
but anyways, i mention this because you can buy bass traps, panels etc for the whole room for a really low price and then figure out if it work or not without having to sweat the price. Fill the whole room with panels and bass traps and slowly listen the difference.


----------



## gsilbers (Mar 12, 2017)

chillbot said:


> Whatever, Nick.
> 
> I have a lot of expertise in this area here is a rough sketch of what you want to be doing.



and the Himalayan salt lamp? 

Cable covering plants as well.


----------



## wst3 (Mar 12, 2017)

Read between the lines in Nick's post...

Set up the room
Listen
Correct the problems
I don't want to sound snide, but it really is that simple. Well, except for the "correct the problems" part, that could be simple or complex.

You have a couple things working to your advantage, the rooms is not square, so treating room modes will not be awful. And the layout is somewhat symmetrical, which is a big help.

If I were in your shoes I'd set up my gear, stick the monitors somewhere, and listen. Then I'd move the monitors and listen some more. It is difficult to predict optimal placement of the loudspeakers and your ears. You can get good at guessing if you build a few rooms, but you are still guessing.

There is software out there that can model acoustical spaces, but it works much better on large spaces (it barely works for small critical listening spaces), and it costs more than you are prepared to pay for the treatments. So let trial and error be your friends.

And avoid tuned solutions if you can. Sometimes you can't, but a tuned trap can introduce as many problems as it solves.

And be very careful of any and all free advice - even this!


----------



## synthetic (Mar 13, 2017)

I strongly disagree with Nick. I think your acoustic trapping plan is the bare minimum I would want in that room. I just lost my mind and put in tons of trapping in my studio. It looks insane but sounds AMAZING. I have 8' tall corner traps in the front corners now, and 45 degree to either side of me at the ceiling. As long as you combine bass trapping with absorption you negate most of the low frequency buildup you get with excessive absorption alone. And a room that size wouldn't benefit from diffusion, you're better off with absorption. 

Here's a pic I took during construction. 



I built all of these traps myself. They are very easy to make and end up costing under $20 each. Go buy some 703 or 705 fiberglass, I prefer the more rigid 705. In Los Angeles you can buy this from CWCI insulation in City of Industry. Get some 1x2s from Home Depot and build a frame for the fiberglass (inner dimensions 24x48", outer 25.5 x 49.5.) Go to a fabric store and get some upholstery fabric (in Los Angeles go to Michael Levine downtown, I used fake suede.) Stretch this fabric over your frame and staple it to the back. Push the fiberglass in (wear gloves and long sleeves), get some picture hanging wire, and put them on your wall. For the corner traps go 2-layers deep (2") or more, you have to cut the fiberglass at a 45° which sucks. These traps are identical to the ones you buy for $300 a pop at retail, except they look better. 

I was actually thinking about upgrading my monitors before doing this. Now it sounds awesome in there. I already did a quick mix and now EQ is so much easier to hear and carve. I'll post a pic of the final if anyone is curious. 

Nick and I have been arguing about absorption for years. Nick, come to my studio and I'll prove you wrong once and for all.


----------



## synthetic (Mar 13, 2017)

Also, consider a ceiling cloud. Really helped me to hear imaging.

Most acoustic companies like GIK and Auralex will send you a free design recommendation. To sell their products of course but it might also be helpful if you want a professional opinion.


----------



## synthpunk (Mar 13, 2017)

DYI is the way to go if you go this route.

Just one very important skull and crossbones note of caution... beware of any loose fibers that can float around your room and end up inside your lungs not a good thing whatsoever. I would also advise keeping your room well-ventilated at all times.



synthetic said:


> Also, consider a ceiling cloud. Really helped me to hear imaging.
> 
> Most acoustic companies like GIK and Auralex will send you a free design recommendation. To sell their products of course but it might also be helpful if you want a professional opinion.


----------



## Nick Batzdorf (Mar 13, 2017)

> Nick and I have been arguing about absorption for years. Nick, come to my studio and I'll prove you wrong once and for all.



You're on, Heffe!

But don't expect it to prove either of us wrong or right. I'm sure it sounds great. My argument isn't that side mufflers always sound bad, it's that they don't help the imaging - and that there's zero scientific basis behind the conventional "imaginary mirror" old wives' tale.


----------



## synthetic (Mar 13, 2017)

Nick Batzdorf said:


> it's that they don't help the imaging - and that there's zero scientific basis behind the conventional "imaginary mirror" old wives' tale.



Well, the theory is to absorb or diffuse first-order early reflections as much as possible. Because if I'm hearing a lower level reflection 3ms after the initial sound from the speaker from the other side of the room, it's just going to confuse the left/right image or cause phasing problems. And the first order reflections (single-wall bounce) are going to be higher in power (volume) than 2nd, 3rd, etc. So try to reduce those first-order reflections where possible, especially right up in the mix area. That's where the mirror trick* comes in, the strongest reflection you can generate is from the speaker to the wall right next to you. The second strongest is going to be from the ceiling, because that's probably the next-closest surface in a typical bedroom. 

F Alton Everest is in my posse on this. 

* put a mirror on the wall, move it until you can see your tweeter from the mix position, then put absorption there.


----------



## synthetic (Mar 13, 2017)

synthpunk said:


> Just one very important skull and crossbones note of caution... beware of any loose fibers that can float around your room and end up inside your lungs not a good thing whatsoever. I would also advise keeping your room well-ventilated at all times.



I build the panels outdoors. But the 705 fibers don't tend to float, they're pretty heavy. Unless there's an invisible cloud that I was breathing, in which case see ya later.


----------



## Nick Batzdorf (Mar 13, 2017)

> Well, the theory is to absorb or diffuse first-order early reflections as much as possible



I know that's the theory, and it's wrong. As I keep saying, your brain separates sounds coming from different angles all day long. Microphones don't, brains do.


----------



## wst3 (Mar 13, 2017)

I really wish I could share some of the AES and ASA papers on this topic, but of course I can't. There has been a great deal of effort put into understanding how early reflections work (or don't work<G>) in a small, critical listening space. The jury is still out, it's probably too early to say the older theory is incorrect, but it is certainly under the micropscope.


----------



## synthetic (Mar 13, 2017)

Whatev, my crib sounds tight. Even if it (appropriately?) looks like a padded cell.


----------



## synthpunk (Mar 13, 2017)

Actually you should also let you panels vent outside for a few days before installing.

Do you think 705 is the best choice over Roxul? 



synthetic said:


> I build the panels outdoors. But the 705 fibers don't tend to float, they're pretty heavy. Unless there's an invisible cloud that I was breathing, in which case see ya later.


----------



## Nick Batzdorf (Mar 13, 2017)

Okay Bill, let me put it this way: nobody has ever heard side bounces comb filter with the sound straight from the speakers in the history of mankind.

But the jury is still out.


----------



## FriFlo (Mar 14, 2017)

Why do people always think, they can just purchase some panels to make a room sound better ... well, I must remember, I thought that as well some time ago.
Dude, I don't want to belittle you, but this is a tiny bedroom studio and you have obviously no idea about acoustics. Reading in some forums won't change that, so it is better to not spend money on acoustics at this point.
Should you consult a professional studio builder? Well, yes, but no. Anybody should, who doesn't really know what he is doing. However, this room is not going to be worth investing so much money into.
My advice is, learn about acoustics with a good book and try to apply that on the speaker placement, which leads to more results than any treatment you could buy. Get Room EQ Wizzard and start measuring. You can learn a lot by that, but it will take you long.
If all of that sounds like to much work, don't worry and just make some music. If you are composing, you get paid (hopefully) for your good ideas and a good rough mix. Productions that have to be that stellar have the budget to give the mix to a dedicated engineer and possibly mastering on top. So, you just need to concentrate on being good with what you have.
Trust me, I know you will think back at this, when you are going to find out, how much money was wasted ...
If anything, go with the beer fridge design!


----------



## FriFlo (Mar 14, 2017)

synthetic said:


> I strongly disagree with Nick. I think your acoustic trapping plan is the bare minimum I would want in that room. I just lost my mind and put in tons of trapping in my studio. It looks insane but sounds AMAZING. I have 8' tall corner traps in the front corners now, and 45 degree to either side of me at the ceiling. As long as you combine bass trapping with absorption you negate most of the low frequency buildup you get with excessive absorption alone. And a room that size wouldn't benefit from diffusion, you're better off with absorption.
> 
> Here's a pic I took during construction.
> 
> ...



How are the dimension of your room and do you have a REW picture of you RT60? If the other side of your room is treated as much as the one we see on the picture, you will have to much absorption! The frequency response might look better, but that can be misleading ...


----------



## Gerhard Westphalen (Mar 14, 2017)

synthetic said:


> Well, the theory is to absorb or diffuse first-order early reflections as much as possible. Because if I'm hearing a lower level reflection 3ms after the initial sound from the speaker from the other side of the room, it's just going to confuse the left/right image or cause phasing problems. And the first order reflections (single-wall bounce) are going to be higher in power (volume) than 2nd, 3rd, etc. So try to reduce those first-order reflections where possible, especially right up in the mix area. That's where the mirror trick* comes in, the strongest reflection you can generate is from the speaker to the wall right next to you. The second strongest is going to be from the ceiling, because that's probably the next-closest surface in a typical bedroom.
> 
> F Alton Everest is in my posse on this.
> 
> * put a mirror on the wall, move it until you can see your tweeter from the mix position, then put absorption there.



I suggest checking out the book "Sound Reproduction" where the author goes through a number of studies done on sidewall reflections. It is geared towards more casual/audiophile listening instead of for mixing but what he says largely transfers over. I'm planning to take down my sidewall panels this summer and see if I prefer without them there.


----------



## FriFlo (Mar 14, 2017)

synthetic said:


> Well, the theory is to absorb or diffuse first-order early reflections as much as possible. Because if I'm hearing a lower level reflection 3ms after the initial sound from the speaker from the other side of the room, it's just going to confuse the left/right image or cause phasing problems. And the first order reflections (single-wall bounce) are going to be higher in power (volume) than 2nd, 3rd, etc. So try to reduce those first-order reflections where possible, especially right up in the mix area. That's where the mirror trick* comes in, the strongest reflection you can generate is from the speaker to the wall right next to you. The second strongest is going to be from the ceiling, because that's probably the next-closest surface in a typical bedroom.
> 
> F Alton Everest is in my posse on this.
> 
> * put a mirror on the wall, move it until you can see your tweeter from the mix position, then put absorption there.


Yes, but the only good way of doing that is mainly by deflection, not by absorption. Same goes for the cloud: a good one is hard-backed and angled by at least 7 degree. It will deflect direct reflection from the listening position down to the low mid frequencies. Putting 5cm apsorbiton there is just killing more high frequency reverberations, which must be protected, rather than killed, especially in small rooms.
I must admit, I am really not a professional in studio acoustics and I have much to learn ... but I see so many wrong ideas in forums like this. The topic seems to be ideal to be dead wrong on things, while still having the idea of having a certain knowledge. It is very complex, but looks simple on first sight.


----------



## Gerhard Westphalen (Mar 14, 2017)

FriFlo said:


> Yes, but the only good way of doing that is mainly by deflection, not by absorption. Same goes for the cloud: a good one is hard-backed and angled by at least 7 degree. It will deflect direct reflection from the listening position down to the low mid frequencies. Putting 5cm apsorbiton there is just killing more high frequency reverberations, which must be protected, rather than killed, especially in small rooms.
> I must admit, I am really not a professional in studio acoustics and I have much to learn ... but I see so many wrong ideas in forums like this. The topic seems to be ideal to be dead wrong on things, while still having the idea of having a certain knowledge. It is very complex, but looks simple on first sight.



The principle of deflection which you mention makes a lot of sense but it's not something I've come across while researching this (although I have seen it applied in a few rooms). Doing a quick Google search on deflection in studios doesn't turn up much. Any suggestion on resources for finding out more?


----------



## Tanuj Tiku (Mar 14, 2017)

I think Nick and Bill have made some excellent pointers there to start with. There isn't a whole lot you can do in your room but there are things to be done.

First, listen. If you know what a particular recording should sound like with some experience before hand. You will be able to tell what is working and what isn't. Trial and error. Move the speakers and see how it sounds.

Get a basic acoustic control going. There is a lot of bad information out there about bass traps and what not. You need serious trapping going on the lower you go in the frequency spectrum. It is going to be nearly impossible to do that in your room unless you put massive bass traps in the rear of the room. My rear wall is 5 feet deep. But, I do have a larger room with 15 inch LF drivers.

You should definitely listen and try a few things. Ultimately, once you are happy with a decent sound, your ears will get used to the room and you can go from there.

It is all a compromise, you just need to make the best one.

Near fields are probably going to be better in a room like yours.

Also, you do not need rockwool or glasswool to make this work. It is difficult to work with and loose fibers can cause some health issues if not done right.

You can however use cotton waste felt. Or cotton wool as it is known as in some countries. It is very cheap and works just as well. However, you will need different quantities. Some research on this will help on Gear Slutz or if you can speak to someone who knows about this.

You could also look into Celenit or wood wool boards. They are made of pine wood shavings. They are not very expensive and can absorb a wide range of frequencies. 

If you really want to learn more, grab Philip Newell's Recording Studio Design book. There are a few other books which are also good. Go through them and go from there. If anything, it will make you understand the basics of acoustic design.

I have attached a picture from my build which shows the cotton waste felt and celenit boards (in the ceiling). The good thing about the felt is that it is made from cotton so it is very easy to work with and causes no itching or eye burning. Very natural and works just as well. 

You can use the usual white adhesive and try to make all your panels from pine wood or something similar. Plywood can come with formaldehyde which is heavier and as a result will settle in your room. And if you do not have a source of fresh air, it will irritate your eyes and throat as it releases the gas. 

Do think about a source of fresh air. It will keep you fit and going for long hours. Make sure your electrical layout is decent and can function without problems for your equipment. 

And enjoy making/mixing music!


----------



## FriFlo (Mar 14, 2017)

Gerhard Westphalen said:


> The principle of deflection which you mention makes a lot of sense but it's not something I've come across while researching this (although I have seen it applied in a few rooms). Doing a quick Google search on deflection in studios doesn't turn up much. Any suggestion on resources for finding out more?


Sure! A good resource to get informed about proper studio building is the John Sayers forum. Deflection works best with completly shaping the room with dry wall and achieve a symmetrical build with non-parallel walls. This can also be combined with soffitmounted speakers. I didn't have the space to make a room in room construction, but I did build a soffit mount construction for my speakers.
Deflection can also mean treatment, like angled slat resonators, polycylindrical diffusers, etc. Where to use what takes a lot of experience, so I will admit freely, that I would always consult someone with that skill and experience level. If you built devices your self this is well worth the money, as you will be pretty frustrated, when something was wrong after spending so much time on building. To many people think, it is just about looking at a frequency curve. Then, if patient, they realize there are things like decay, also dependent on frequency! Then they realize there is much more stuff and all is kind of related to each other. It is like tuning a grand piano. In theory, it looks easy to a novice! However, most people do realize, they should tune wir piano themselves. But so many think, they can improve their room sound, which is really wrong on most cases.


----------



## wst3 (Mar 14, 2017)

Actually there is quite a bit of literature on reflection vs absorption vs diffusion, RPG and ASC both have (had??) good papers on the topic.

All three are tools, and all three can be used to great advantage.

I've mentioned before, some of my favorite recordings were mixed in really horrible little rooms with minimal treatment.

It is easier to make tracking and mixing decisions in a well behaved room, but it is possible to work, and make good decisions in a room that is not quite optimal.


----------



## Ashermusic (Mar 14, 2017)

My room treatment? Bookcases, lots of them with staggered book protrusions.


----------



## wst3 (Mar 14, 2017)

Ashermusic said:


> My room treatment? Bookcases, lots of them with staggered book protrusions.


That can be really effective! It provides absorption (mostly upper octaves) and diffusion (although the pattern isn't terribly well defined). And that can be more than enough, especially for a composer.


----------



## Ashermusic (Mar 14, 2017)

wst3 said:


> That can be really effective! It provides absorption (mostly upper octaves) and diffusion (although the pattern isn't terribly well defined). And that can be more than enough, especially for a composer.




Nick came here and thought it was reasonably effective, especially since I have one faux brick wall.


----------



## Uncle Peter (Mar 14, 2017)

I constructed this spreadsheet a few years ago to determine any problem frequencies based on your room dimensions.
https://dl.dropboxusercontent.com/u/15309428/Room%20Modes.xls

From memory, the theory on the RoomModes tab is all good. The Results tab has some formulae which are just my construction - attempting to identify where some frequencies might be clustering. E.g. whether an axial mode frequency is more or less combining with a tangential mode frequency etc..

Basic instruction:
1. Enter your room dimensions in the yellow boxes
2. Click process results and view the results in the Results tab.
3. Alter the yellow threshold box (E37) in the results tab to alter the sensitivity to clustering. The red labels highlight any problem frequencies. You may wish to alter how the clustering is flagged.

So if for example you have more low frequency issues then probably best to focus on the bass trapping.


----------



## wst3 (Mar 14, 2017)

I've seen that spreadsheet before! Not sure where, but it really is pretty cool. I built one that graphed the results, no idea what I did with it. A long time ago I wrote a program for the HP-41 to do the same thing - dang!

Jay - I have no doubts your room sounds pretty good, I also suspect you know it inside and out!


----------



## Uncle Peter (Mar 14, 2017)

wst3 said:


> I've seen that spreadsheet before! Not sure where, but it really is pretty cool. I built one that graphed the results, no idea what I did with it. A long time ago I wrote a program for the HP-41 to do the same thing - dang!
> 
> Jay - I have no doubts your room sounds pretty good, I also suspect you know it inside and out!


Ha, that's interesting - I have shared it before I think. Otherwise someone else must have done the same thing (inevitably).


----------



## synthpunk (Mar 14, 2017)

Our 110 lb black lab mix makes a good bass trap and we can move it around pretty easily


----------



## Nick Batzdorf (Mar 14, 2017)

Friflo:



> The frequency response might look better, but that can be misleading ...



That's right.

And as with everything else, the ears come first! Measuring is great, but we all have a sense for what sounds right.
Jay:



> Nick came here and thought it was reasonably effective, especially since I have one faux brick wall.



Yeah, your room sounds good. My only suggestion at the time was to move your speakers back a little, because they weren't "breathing." If I remember right there were practical limitations on exactly where you could put them, which of course is the rule with acoustics rather than the exception.


----------



## synthetic (Mar 14, 2017)

FriFlo said:


> How are the dimension of your room and do you have a REW picture of you RT60? If the other side of your room is treated as much as the one we see on the picture, you will have to much absorption! The frequency response might look better, but that can be misleading ...



No, the back is more open. I plan to add diffusion back there when I can afford it. I won't make that myself, I'll probably buy GIK Alphas for back there. I want to keep that a bit more live so I can record in that space. (Or closer to the front if I want a deader sound.) 

I measured before and after installing the latest traps. I already had corner traps but they were half the size. I have a calibrated Earthworks mic and I used Room EQ Wizard for the measurements. The before measurement showed mostly flat but with some peaks and one massive well around 220Hz. The before measurement had a swing of 39dB. After the latest treatment it's closer to 24dB. Which isn't perfect (nothing is) but probably as good as I can get without massive investment and construction. If I had infinite budget I might add QRD to the front wall to break up any bass radiation from the monitors but I think the difference would be minimal. 

My main goal was to clean up the 100-300 range, and that range was improved by nearly half 20 dB – swings went from 39dB to 20dB. I threw up a mix and that frequency range is sooo much easier to mix now. No more rocking and guessing for EQ frequencies, and I can hear minor changes very clearly. Imaging and depth of field is also improved. Like I said, I was thinking about upgrading monitors before but now I am very happy with the sound. 

My room is 19' 1.5" x 11' 8.25" x 7.96'. That puts me in the Bolt Area to reduce nodes building on top of each other. I wanted an arched ceiling but we didn't have the budget, and non-square rooms are harder to calculate anyway. 

If you want to learn more about this subject, "The Master Handbook of Acoustics" by F Alton Everest is the standard. It doesn't include all of the latest diffusion techniques, but otherwise it is very thorough.


----------



## synthetic (Mar 14, 2017)

I believe the "bookcase as diffusor" myth came from Bill Botrells old studio in Pasadena. Walters Storyk (?) built him custom diffusors made from old books. But they *cut the books* and glued them in a mathematical sequence to make it work. If you get one digit wrong in that sequence, the diffusor doesn't work at all. Math is freaky. 

But the picture was in Mix Magazine and the legend grew.


----------



## synthpunk (Mar 14, 2017)

I have also started a dedicated DIY Room Treatment thread on the Gear Talk sub forum if anyone wishes to participate please do. I am hoping that will develop as a sort of FAQ and then we can pin it.

http://vi-control.net/community/threads/diy-room-treatment-thread.60572/


----------



## Gerhard Westphalen (Mar 14, 2017)

synthetic said:


> My main goal was to clean up the 100-300 range, and that range was improved by nearly half 20 dB – swings went from 39dB to 20dB



Are you saying that there were fluctuations on the REW graph of +/-39dB?


----------



## synthetic (Mar 14, 2017)

no 39dB peak to trough


----------



## wst3 (Mar 14, 2017)

synthetic:



> I believe the "bookcase as diffusor" myth came from Bill Botrells old studio in Pasadena. Walters Storyk (?) built him custom diffusors made from old books. But they *cut the books* and glued them in a mathematical sequence to make it work. If you get one digit wrong in that sequence, the diffusor doesn't work at all.


Not exactly - the sequences used in 2D and 3D diffusors provide a "well behaved" and predictable diffusion pattern, where a random sequence of books (or anything else) will provide a more random pattern. Both will diffuse the energy that strikes them, you just might not like the results from a purely random pattern - or you might<G>!

synthetic:



> Math is freaky.


But it is also very cool (had to say that since it is March 14)


----------



## Nick Batzdorf (Mar 14, 2017)

I think whether you like it is going to depend on where it is. If it's 3' away on the sides, maybe not, but a bookcase 8' behind you is going to be fine.

At least it is in my room.


----------



## synthetic (Mar 14, 2017)

Everest has a cool example in his book of a diffusor that didn't work. A team builds an optical diffusor in the lab (same principal) and it didn't work at all. They studied it under a microscope and realized they got one digit of the sequence slightly wrong. So instead of "374693..." it was "374593..." or something. They fixed that error and it worked perfectly. It went from 0% to 100% with that small correction. So yes a group of books technically diffuse sound, because the sound bounces off of them and scatters. But it's not even close to being a real diffusor.


----------



## babylonwaves (Mar 15, 2017)

for everybody interested in all this: here's a book i can really recommend:

Focal Press
The Acoustics And Psychoacoustics Of Loudspeakers And Rooms (Floyd Toole)

https://www.amazon.com/Floyd-Toole/e/B001JS2MQ2/ref=dp_byline_cont_ebooks_1


----------



## wst3 (Mar 15, 2017)

Agreed - Floyd Toole is the man behind a number of audio breakthroughs. His book is very readable, and should be useful to someone trying to treat a room.

If you want to learn more about diffusers you might want to read https://www.amazon.com/Acoustic-Absorbers-Diffusers-Third-Application/dp/1498740995/ref=sr_1_1?s=books&ie=UTF8&qid=1489578507&sr=1-1&keywords=Peter+D%27Antonio+diffusers (Acoustic Absorbers and Diffusers, Third Edition: Theory, Design and Application)by Trevor Cox and Peter D’Antonio - Dr. D'Antonio founded RPG. This is not a cheap book, but well worth it.

Lastly, anything by Philip Newel is worth reading!


----------



## wst3 (Mar 15, 2017)

synthetic said:


> Everest has a cool example in his book of a diffusor that didn't work. A team builds an optical diffusor in the lab (same principal) and it didn't work at all. They studied it under a microscope and realized they got one digit of the sequence slightly wrong. So instead of "374693..." it was "374593..." or something. They fixed that error and it worked perfectly. It went from 0% to 100% with that small correction. So yes a group of books technically diffuse sound, because the sound bounces off of them and scatters. But it's not even close to being a real diffusor.


We will have to agree to disagree. In his book Everest is talking about the pattern that is created, and the error in the sequence prevents the pattern from following specific rules. It is still very much a diffuse field. If you dig you'll also find that Everest (and others) suggest that you need at least 11-12 feet for a diffuse field to develop (that depends on the type of diffuser, and I don't remember which is which).


----------



## babylonwaves (Mar 15, 2017)

and while we are at it, this is a good overview to start with:

http://www.soundonsound.com/techniques/making-space


----------



## colony nofi (Mar 18, 2017)

Some great references here. Everest, D'Antonio, Cox, and Toole will give you a good amount of bedtime reading... and possibly pull you into a world that is difficult to escape. But it can be a lot of fun...

This is not to say you can't compose a beautiful piece in a bedroom with zero treatment. But there are different emotional / phychological reactions to being in different sounding rooms, and they will effect what you write. Just as the ideas of natural light, light off of computer screens, the aesthetics of the space, the size of the space, how comfortable you are physically, the distractions, outside noise, etc etc. So when thinking about rooms, we need to think about all of these. And have something in mind that you want to measure it against - what your ideal actually is. Weight the different parts that are important to you. 

Sometimes composing on a train with headphones creates an environment that opens up ideas you would have never had in the best sounding room in the world.

But I will say I love having my music mixed in a lovely sounding (and therefore pleasingly feeling) room.....


----------



## FriFlo (Mar 18, 2017)

synthetic said:


> No, the back is more open. I plan to add diffusion back there when I can afford it. I won't make that myself, I'll probably buy GIK Alphas for back there. I want to keep that a bit more live so I can record in that space. (Or closer to the front if I want a deader sound.)
> 
> I measured before and after installing the latest traps. I already had corner traps but they were half the size. I have a calibrated Earthworks mic and I used Room EQ Wizard for the measurements. The before measurement showed mostly flat but with some peaks and one massive well around 220Hz. The before measurement had a swing of 39dB. After the latest treatment it's closer to 24dB. Which isn't perfect (nothing is) but probably as good as I can get without massive investment and construction. If I had infinite budget I might add QRD to the front wall to break up any bass radiation from the monitors but I think the difference would be minimal.
> 
> ...


I would strongly take my vote against QRD diffusers for your room. They have become quite a popular device, probably because they look cool and are easy to ship and therefor make money on. But in reality, they are impractical for most people! You need at least 3 m distance between your listening (or recording) position for them not to produce artifacts. This means, you move your head an inch and the frequency response changes! It doesn't look like your room is anywhere near big enough for QRD diffusers to be good. Do yourself a favor and build yourself some polycylindrical diffusers (just 5mm piece of bent plywood over mineral wool). It's a little time-intensive to build them, but fairly easy and it will improve both your listening via the speakers and recording, while the QRDs will only provide unforseeanble results.


----------



## synthetic (Mar 20, 2017)

I'm not putting in QRD, I'm using binary amplitude diffusion (GIK Alpha). Much more effective at short distances and better temporal diffusion than cylindrical polys.


----------



## wst3 (Mar 20, 2017)

FriFlo's suggestion for polycylindrical diffusers is a great idea!


----------



## Flaneurette (Apr 3, 2017)

I know this will largely be ignored, but if you are serious about mixing:

1. Consider another room. (probably not what you want to hear)

2. Hire someone who actually builds and treats studios on a daily basis, or, -if you can find one- an acoustician. Otherwise you will waste time and money. When hiring a professional, you only waste money. 

If you still want to DIY, maybe have a look at this guy's YT channel He's one of the few YT'rs who actually knows what he talks about.



$1000 Budget:


----------

