My multi location subwoofer thread inspired by Welti,Devantier,Geddes !!! - Page 3

Good points, I'm trying to take in all I can wrt acoustics,...it's like a fractal, the more I learn, the more I learn I don't know



What paper?


Thanks

Absolutely.

Got it, misunderstood

Thanks

Yes, but remember the only way to get efficiency at low freq is with size; it would take a ported box of several cf.



No, this one:

http://www.harman.com/EN-US/OurCompa...s/multsubs.pdf

I believe Geddes more or less pooh poohs it, saying it's too idealized to work in real rooms.

Seems to work in mine though, and it's from from the closed rectangular room the theory is based on.

I've been hanging out around the acoustics area here at AVS, GearSlutz, reading SAC, and many studio design engineering/architectural articles everywhere I can find them. I've been reading, re-reading, Toole's most recent book. I carry it and Everest's Master Acoustics book with me as I run errands etc., any extra moment I have I dig in.

Several months ago, I began performing a variety of long term experiments in my room. This began with a discussion/disagreement between myself, and Dennis Erskine. Ethan Winer chimed in, however he's been very busy with a book he working on (due out sometime soon). We started discussing Toole's assertion regarding first mirror point reflected energy in typical small rooms, and how one interprets that in their own room.

Since that brief exchange, I've taken down all my treatments and have been listening to different mains, in various situations. Diffuse, scattering, absorption, totally reflective, re-directive with the energy, etc., I haven't tried everything, but it's been fun trying the combos I have tried. Upon starting down this route, I decided to really dig deep and spend significant time on as many combos of acoustic models and environments. I've discovered some really cool aspects that apply to my room. I do measure, but I'm trying to assign characteristics for each avenue, at the LP in my room,..as that's all that matters. This isn't a dedicated room, it's a family room that all four of us share,..so everyone's been very patient thru this process.

All this theory, but what really matters is my room, at the LP. Each aspect impacts other elements, and many acoustic answers are "it depends"...true. I'm trying to determine new mains for purchase. I've considered tightly pattern controlled mains, but that un-necessarily limits lateral energy components,... which may or may not be needed. Yes, a tightly controlled directivity is ideal for many apps. But too much pattern control, in the wrong room, doesn't allow you to utilize the side wall interaction if you need it. From what I've discovered in my room, I want it available in a controlled amount.

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kgveteran
I really like those diffusers/scattering panels you made,...and the pics I've seen of your room. And when you began with your OmniMic work/subs, I was interested on seeing what you'd discover. Your small sealed filler subs will be quite interesting too. I think they need to be fairly robust, but nothing exceptional. I'd want them to do more than just fill in. Just my approach, my 2 cents I certainly not the most savvy small sealed DIY'er around.


Continued good luck, sorry for the OT

Geddes can have pretty incisive words, and tends to dismiss much of what does not align to his product line.

I use the Toole/Welti/Devantier method, and it works for me. My subs are at the front wall's 1/4 points. At some point, I do want to add some rear subs.

Either method works. The one thing both have in common is measurement to confirm....the most impotant part, IMO.

JSS

This can be at least partially achieved by toeing them in, which will give a delayed reflection from the opposite side wall.

When the minidsp arrives I would try inverting the phase. I had a similar issue with my FR and once the phase was inverted the huge null had almost vanished. A few weeks back I spent a number of hours painstakingly changing the distance on my subs by .2 feet +/- to smooth out my FR at the crossover. I was able to achieve mildly acceptable results. It might be worth spending an hour or two to measuring and changing the sub distance.




Forin

I have been following this for a while. I am very interested in seeing your results.

http://www.aes.org/tmpFiles/elib/20120309/13680.pdf

I know what I will be reading today.

Looking good KG!!!