Excellent article about small room acoustics

[vespiz]

Well, take that 1:1.14:1.39 ratio for example.
It means that if you have a height of 10 feet, then the ideal measurements would be 11,4 feet for width and 13,9 feet for length.

Right?

 

[Eschatologist]

*Sigh* That graph pretty much describes my little studio room....

 

[James-Doolan]

http://downloads.bbc.co.uk/rd/pubs/...tural-acoustics/bbc_guideacousticpractice.pdf

skip to section 3 or read the whole thing if you have a lot of time on your hands

 

[smy1]

Would one solution be to completely cover all the walls/corners with broadband absorbers as well es building a cloud over the mixing spot?

 

[Splat88]

I can speak from experience though, the nulls are what really kill you. That 80Hz null on the plot above would make mixing low-end horrid in that space. I have the same sort of thing except ranging from 90hz to 110hz.

I have this same problem with my current mixing setup. I've been mixing in the same 10x10 room since 2004 and the first thing noticed after coming from a large room was that my monitors had absolutely no low end. just a big indistinguishable blurry mess. That's why I mix almost exclusively on headphones anymore, but that opens up a whole other can of worms. The good news is that my wife and I have our house on the market. Now that we have two kids, we need a bigger house so I can still have a dedicated room to mix and keep all my shit in! Whenever that move occurs, I can guarantee that a nice mixing room will be factored into our house buying decision.

 

[Soundlurker]

Thanks for that BBC link, there's some useful stuff in there

 

[James-Doolan]

Thanks for that BBC link, there's some useful stuff in there

No prob takes a little bit of time to sift through the information though

 

[Melodeath]

How do I plot a frequency graph like that? I just made a recording of my room with that SONAR project file on Ethan's site.

 

[SocialNumb]

Well, take that 1:1.14:1.39 ratio for example.
It means that if you have a height of 10 feet, then the ideal measurements would be 11,4 feet for width and 13,9 feet for length.

Right?

I'm going to check out the Modecalc program on the site later on. Will report back here. (I probably won't know what I'm doing )

 

[Ermz]

Thanks for the link Ermz.

My band actualy just moved into our monthly rehearsal spot. It is about 15'x15', open ceiling with some ventilation shafts and pipes exposed. It is the roof of the building actually.

Is there some better info. I can find regarding what broadband absorbers are, what they do, maybe how to build some, and the ideal placement?

I get the basic idea of a bass trap, but am not sure if I should just build some of those, some broadband absorbers (or both), and where to place em.

Thanks,
-Joe

In most cases you'd want to treat a rehearsal room as a 'live space'. That usually entails lots of bass trapping and a fair amount of diffusion rather than just plain absorption. Since diffusors are pretty hard to build DIY, you may just have to settle for broadband absorption.

It's very simple really. In all the room corners build superchunk bass traps (look for info on these in the John Sayers and GS Acoustics forum). These are very effective broadband bass absorbers if you use the right insulation. Along all the parallel walls put broadband absorber panels. If you have any more willpower left after all this then straddle every open corner in the room with broadband absorbers. You can never have too much bass absorption, so go crazy!

 

[J.DavisNJ]

In most cases you'd want to treat a rehearsal room as a 'live space'. That usually entails lots of bass trapping and a fair amount of diffusion rather than just plain absorption. Since diffusors are pretty hard to build DIY, you may just have to settle for broadband absorption.

It's very simple really. In all the room corners build superchunk bass traps (look for info on these in the John Sayers and GS Acoustics forum). These are very effective broadband bass absorbers if you use the right insulation. Along all the parallel walls put broadband absorber panels. If you have any more willpower left after all this then straddle every open corner in the room with broadband absorbers. You can never have too much bass absorption, so go crazy!

Thanks man. I'm just looking to optimize the sound in the most cost effective way. Right now the walls are totally bare and the sound reflects like a motherfucker! We play loud as shit too.

-Joe

 

[Ermz]

Cool. If you do it right you will find that intelligibility within the room will improve a ton. You will actually be able to hear each other and everything will sound much tighter. The room plays a MUCH greater role in what we hear than most people realize. It's massive, really, way more important than even switching monitors.

 

[J.DavisNJ]

Cool. If you do it right you will find that intelligibility within the room will improve a ton. You will actually be able to hear each other and everything will sound much tighter. The room plays a MUCH greater role in what we hear than most people realize. It's massive, really, way more important than even switching monitors.

Cool, I'm excited. The corners I think I can build no problem.

What should I do about the broadbands? Buy pre-existing dealies?

I haven't seen many tutorials on building broadband absorbers so I'm a bit in the dark about em.

-Joe

 

[Ermz]

It's very simple. All broadband absorbers are, are frames with a cloth covering that contain a panel of insulation material. You're in the states so Owens Corning 703 is your best bet. It's rigid fibreglass insulation that will stand up by itself, so all you need to do is create a wooden or metal frame for it and cover it in some kind of cloth that's breathable (poplin worked well for me!). If you have some handyman know how it's fairly basic stuff. But if you can't be arsed then GIK Acoustics and Realtraps should be your next stop!

 

[J.DavisNJ]

It's very simple. All broadband absorbers are, are frames with a cloth covering that contain a panel of insulation material. You're in the states so Owens Corning 703 is your best bet. It's rigid fibreglass insulation that will stand up by itself, so all you need to do is create a wooden or metal frame for it and cover it in some kind of cloth that's breathable (poplin worked well for me!). If you have some handyman know how it's fairly basic stuff. But if you can't be arsed then GIK Acoustics and Realtraps should be your next stop!

Thanks Ermz, much appreciated again.

That sounds exactly like every bass trap tutorial that I have seen floating around. What would the difference be really? Less insulation, more?

Also, for the corner traps, would it make any difference to build them as wedges or to just use a rectangular shape and prop it in the corner?

Thanks again,

-Joe

 

[Ermz]

Hey joe,

The superchunk method is to cut triangular pieces from your insulation panels and stack those in the corners from bottom to top. This is the most effective corner trapping method because you're filling the entire corner, with no air gaps left for the low-end to escape. Do these in as many corners as you possibly can. It's very straightforward, all you do is cut and stack, and then stabilize them somehow, and cover with material after to stop the fibers from floating around.

Check the GS Acoustics forum for tutorials on building broadband absorbers. You will find what you need to there. Lots of people doing it a few different ways. Some end up looking and functioning more professional than others.

 

[vespiz]

I'm going to check out the Modecalc program on the site later on. Will report back here. (I probably won't know what I'm doing )

Ah, just to clarify, Modecalc is used to calculate the room modes, ie. those frequency build-ups that cause the most problems. You measure the room (height, width and length), enter those into the room and it shows the modes. It also states some ideal room ratios, where these modes are spaced apart so as to not cause that much trouble. I'm making it sound more complicated than it really is...

Why use it? Well, you could always try guessing what's wrong with your room, but with this, you can calculate what's being caused by the room (dimensions) and not by something else.

Still, the answer is after all measurements... more bass trapping!! :Smokin:

 

[vespiz]

Hey joe,

The superchunk method is to cut triangular pieces from your insulation panels and stack those in the corners from bottom to top. This is the most effective corner trapping method because you're filling the entire corner, with no air gaps left for the low-end to escape. Do these in as many corners as you possibly can. It's very straightforward, all you do is cut and stack, and then stabilize them somehow, and cover with material after to stop the fibers from floating around.

Check the GS Acoustics forum for tutorials on building broadband absorbers. You will find what you need to there. Lots of people doing it a few different ways. Some end up looking and functioning more professional than others.

Very easy and highly recommended.

The "ghetto" way is to buy them in rolls/packs, stack these packs into the corners and just cover with a cloth so that the place doesn't look like a construction yard.

 

[Ermz]

. more bass trapping!! :Smokin:

Yes, always more bass trapping in smaller rooms!

It's not even the nodes that are so problematic. I mean sure the modes in the sub frequencies that cause large booming can be problematic, but they are nowhere near as devastating as the nulls. Having the range from 80 to 120hz sucked out almost 30dB is nothing short of catastrophic for mixing. The only way to fix that in a smaller space is by cramming everything with insulation. You can move yourself and your speakers around all you want, but all you are doing is shifting the null to a slightly different location.

Bear in mind the article which I linked. It highlights that smaller rooms are subject to even more issues than the simple, mathematically-calculated modes. I won't try to explain it here, so everyone who's currently in the 'modes' mindset, look it over. The modes essentially don't matter, because there are so many peaks and nulls in small rooms spaced so closely to each other all you can really do is opt for a broadband approach. Having a tuned resonator is no use to you because you likely need in excess of 10 of them! Once again, article says it better than I!

 

[vespiz]

Yes, always more bass trapping in smaller rooms!

It's not even the nodes that are so problematic. I mean sure the modes in the sub frequencies that cause large booming can be problematic, but they are nowhere near as devastating as the nulls. Having the range from 80 to 120hz sucked out almost 30dB is nothing short of catastrophic for mixing. The only way to fix that in a smaller space is by cramming everything with insulation. You can move yourself and your speakers around all you want, but all you are doing is shifting the null to a slightly different location.

Bear in mind the article which I linked. It highlights that smaller rooms are subject to even more issues than the simple, mathematically-calculated modes. I won't try to explain it here, so everyone who's currently in the 'modes' mindset, look it over. The modes essentially don't matter, because there are so many peaks and nulls in small rooms spaced so closely to each other all you can really do is opt for a broadband approach. Having a tuned resonator is no use to you because you likely need in excess of 10 of them! Once again, article says it better than I!

True. Maybe I ought to read the article? I'm trying to keep things simple here, not everyone understands acoustics so why not start at something that's pretty simple to understand? I'm not saying that I understand all of it, far from it, but I've learned something along the way and I'm willing to learn more!