Sean,
> Do you personally believe what all the other manufacturers say? <
Heck no! I'd say that 90 percent of these vendors are absolutely clueless. I know many of them personally.
> I just don't like to see people blindly following acoustic treatment recommendations from manufacturers <
I agree completely. See above.
> In many cases, there are less expensive solutions available for the do-it-yourselfer. <
Of course, but that's not the issue. Heck, why spend $4,000 for a high-end tube preamp when you could build it yourself for only $100? Why pay Dell or Gateway to build you a computer when you could buy a motherboard and power supply and RAM etc and DIY for hundreds less? No question, DIY is a great way to save money if you know what you're doing and your time is worth less than the price difference. I've been pushing DIY room treatment since before the Internet.
> I would love to chat at length with you about all this sometime. <
That's exactly why I'm here, so let's discuss. I see a lot of misinformation about acoustics and treatment from people who have little knowledge but express strong opinions anyway. I'm currently involved in a dissusion elsewhere with a guy who believes EQ is a satisfactory substitute for bass traps, yet he freely admits he's never even heard a room with bass traps. Think about that! I promise you my only agenda is educational, not commercial.
> Storyk and Moulton ... apply different techniques than what you offer, like room shape <
I never said that room shape is not important! But the vast majority of people I help have no choice but to work in an existing room. As for diffusion, I'm all for diffusion given a room large enough to support it. The main "problem" with diffusion is that good diffusors are complicated - either expensive to buy or difficult and time-consuming to build properly - and the simpler diffusors are worse than a bare wall IMO. Further, as great as diffusion is, it's more icing on the cake than a staple. All rooms need substantial bass trapping much more than they need diffusion. And absorption does 90 percent of what diffusion does anyway. In my opinion of course. And I agree that this is one area where opinion is as valid as the science.
> I also believe some rooms don't need all that. <
All what? A bunch of bass traps? Here's a friendly challenge for you: Show me a low frequency waterfall plot for any smallish room that has no bass traps, where the response does not vary by at least 20 dB and there is not severe high-Q ringing.
> If it is possible to change the shape of the room, for example, that may be more effective than insulation in the corners. <
In fact, the best solution is always both.
> Throwing insulation in the corner of a room does not guarantee that the peaks and valleys at the mix position will magically disappear. <
It does! Well, maybe not disappear, because it's impossible to make any small room even close to flat. But adding eight
good broadband bass traps in the corners of a room
always makes the response and ringing better, and
never makes them worse.
> Early reflections are not all bad, either. <
Okay, here's another friendly challenge for you: Show me a room - any room - that does not benefit from absorption (or diffusion) at the first reflection points.
> I disagree with your statement that low listening levels makes nulls appear worse. <
There's nothing to disagree with, and this can be proven with a simple test. Measure the room once at a low level and again at a high level. You'll see that the
relative response and ringing are exactly the same. The nulls are just as deep at low levels, the peaks are just as big, and the ringing sustains for just as long. (Until you get below the room's noise floor of course.)
--Ethan