Controlling Standing Waves in The Home Studio

Great article again Tim, and very readable for those of us that it was aimed at.

Most of that article is excellent; an easily-digestible, well-written non-technical introduction to the subject. Good on ya for spreading the word!
 
I'm a little reluctant to add a "but", but...
 
Unfortunately, it gets derailed when it turns into an ARC endorsement. I'm not an ARC-hater, but the inconvenient truth is that standing waves and ringing are the main acoustical issues that ARC can't address. 

Thanks for reading the article Bit...I see your point here. ARC doesn't correct the waves other than to time them and change EQ. I think it's the timing that makes a difference with ARC. It doesn't eliminate everything  but it helps make a bad situation better. In short I think ARC minimizes the effects of standing waves.
 
I think treatment should be the first step. I didn't intend it to sound like an endorsement for ARC. I am really happy with ARC and so I guess my enthusiasm for the product shows. My main reason for the ARC pitch was because there are so many people who really have limited options and ARC is simply one of the tools that might help to bring you closer to a better mix in a bad or limited situation. I wish I had tried more of these correction systems but ARC is the only one I have used so far and it has really helped. FWIW I like to hear different OPs on this so thanks!
 
Bat- Thanks for the suggestion.Yes I did leave out vocal recording booths and I should have made mention of them as another way to get better recordings. I know you have invested in those nice sound deadening blankets and that's something I should have mentioned.Kind of a way to make a temporary portable space to record....some of these small home studios though...are small enough to be "booths" in their own right.

What ARC does is compensate for nonlinearities in room absorption and the speakers themselves. In that regard, it does indeed do something positive. But you're absolutely right that it all has to start with acoustical absorption.
 
AFAIK, nobody's come up with a way to electronically compensate for resonance. I have read about an active device that works like noise-cancelling headphones, rebroadcasting an out-of-phase copy of what it picks out of the air. Sounds intriguing, but I'd have to see (hear) it to believe it works.

True, but all it takes is for them to stand around for a second or two to screw with your bass perception.
 
When a drum hit that's 100 milliseconds long rings on for 1000 milliseconds you can't tell where one hit ends and the next one begins. Or you have one bass guitar note that's 10x louder than the preceding note. Or half an octave of bass notes that all sound like they're the same damn note. 

Cool video Mike..I hope you don't mind if I tweet that link....and I'm thinking I might have found my next barbecue grill :)
 
I agree Dave, mere milliseconds is all it takes. I'm sure it would take a little longer though to cook hamburgers.

the term "Standing Waves" comes from the original research, where single, static tones were used to demonstrate their existence. I don't think that the term is misleading if you are approaching this from a math or physics orientation, and an awful lot of musicians have that background - and vica-versa, but that's another tale!

There is a lot of research being done today in the area of digital signal processing to correct room anomalies. It ranges from the active devices mentioned by Bit to equally active arrays of microphones and loudspeakers to insanely narrow bandwidth filters. And all of them show some promise, and all of them cost orders of magnitude more than building a purpose built room<G>!

When you look at the current crop of room correction software tools (ARC, Genelec, etc) you need to really study what they can do, or more to the point, what they can't do. Otherwise you are fooling yourself, which may, or may not be an issue. If you like the way the room sounds after the correction then go for it. If you don't, then you need a little elbow grease.

And the thing is, and a lot of people ignore this at their own peril, the same is true of geometry, absorption, diffusion, and reflection. Even withing the narrow spectrum of diffusion we have multiple ways to diffuse sound, QRDs, Polys, etc, and they too have their strengths and limits.


Here's a silly example... one of the things we need in a critical listening space is the absence of noise, and sometimes we have the complimentary requirement to keep the music in the space, so that it does not become noise elsewhere. So we build an enclosure that isolates the space from the rest of the world.

What happens to the energy then? Yes, it stays in the room, so a well isolated space has MORE problems with standing waves than a poorly isolated space. OK, maybe not so silly after all?
 
So what is a person who wishes to have a reliable, accurate (define accurate!) critical listening system to do?
 
Step 1: figure out what you really need. Isolation, accurate frequency response - and how low do you need it to go, accurate transient response, all of the above? Doesn't matter, just figure out what you need.
 
Step 2: Study! Find out what techniques address your requirements. Read case studies (especially, read about the Tom Hidley designed studio at Masterfonics in Nashville!!!) In general isolation is achieved through mass, and the rest is addressed through some combination of geometry, absorption, diffusion, and reflection.
 
Step 3: Find out what your specific limitations are. Room size, room dimensions, construction, geometry, and fixtures are often the biggest obstacle since most of us have to work with an existing space. OK, so work within that framework!

Step 4: Build something... not quite anything, but you get the drift, try something!

Now 40 years ago I could spend time in studios, some well designed, some not so much. Over time I developed a sense of what worked for me. As an example, as good as modern monitors have become, I miss the Altec 604 family of monitors. That's rock and roll, that's fun!

Sadly it is much more difficult for folks to get that sense today. First, there are fewer studios, second, those studios that are still around are busy, and may not welcome visitors.

Which brings us to software designed to correct room problems...

if you are curious, and you can afford it, give it a try! I don't know that any one of them is better (or worse) than the others, so just give it a spin. Figure out what it can, and can not do for you, in your space.

Just be careful not to believe the hype! None of them will fix room resonance or bad reflections. No matter what the developer claims...

Here is a fairly common demonstration that standing waves do indeed "stand":
 

 
The catch is that you have to listen to an ear piercing test tone. :-)
 

The Big Bang Theory TV show had those guy make one. Except it was a paste when it was just sitting there (forget what it was made out of - something and water) and then they had it sit on top of the speaker (on a clear wrap or something kind of thing) and when the music started, it turn back into a liquid (looking like thick milk) and bouncing around to the music on the woofer of the speaker. (Pasty milky kind of).
 
 
 

https://www.youtube.com/watch?v=2CJJ6FrfuGU
 

This thread is both entertaining and educational. Thanks!!
 
Rocky