[Nordenstam]

Originally Posted by PaulP

So not that small, which helps enormously.

The proportions are quite nice as well.

That's beside the point here. All of our rooms fall into the small room category when it comes to acoustics! It really doesn't matter what size the room is. Honestly! The level of each reflection will still be possible to measure, independent of small or large.

It's no different than looking at frequency response graphs like this:

(chose that image because it reminds of the ETC's! :D )

But instead of scanning left to right from bass to high end, ETC's shows energy vs time. It is what it is, a measurement tool. If you're checking gear, you'll use both frequency response and THD measurements. One doesn't exclude the use of the other.

Originally Posted by PaulP

Which you continue to sidestep, just like your prophet.

It's not part of the ETC ordeal, it's a different subject. If you want to discuss low end treatment, I'll participate if I can contribute anything. My knowledge regarding the issue is highly limited. That's why you wont find me contributing much if anything at all in the umpty threads on the subject.

Originally Posted by PaulP

They're useful for the low end, as you yourself point out.

Yep. At least we can agree on something! :D

Originally Posted by PaulP

I get the feeling you've fallen into a well-layed trap. I hope that you will
get the chance to work on a truly small room sometime. ... I have a feeling most of the testing you describe was done in your
head. Sorry for being blunt.

It's not about prophets or religion. It's a measurement tool that works for determining actual real world events. I use multimeters, SPL meter, oscilloscope, crosstalk, freq response and THD measurements, observe sweeps in spectrum editors to watch for aliasing in digital, think waterfalls are excellent for low end observations in a room and I use ETC's for checking the level of individual reflections. I've done it in my room and I'll do it in a shoebox if needed. The waterfall does not give the same detail as it's weighted towards frequency discrimination, not time discrimination.


Some diffusers on the rear wall:


More diffusers on the same rear wall:


The rear reflection comes around 20ms. There also some other things happening in the comparison, please disregard that. The point is to illustrate that its' not just theory.


Not so smooth overall decay response:


Smoother response:


These pics are NOT made to be easily grasped examples. It's a response to the "pics or it didn't happen" insinuation. Haven't been doing any measurements with the explicit goal to prove any point.

Don't see that it would be different to work on a truly small room. There would still be modal issues and there would still be reflections. We use the treatment we choose and we use the measurement tools appropriate to determine the effect of using the treatment. That's it. No magic trick.

And, just like SAC, you have provided very little in the way of hard directions in measuring a room.

Sorry if I'm being dense now. What is it that you want? I realize it's a too open question, but so is yours.

I can't see much else to add to it. Reflections have energy. ETC's shows the energy for any given reflection. If one wants to absorb that energy, one can check how much energy is being absorbed by using an energy level meter like the ETC. The reason to use the overall ETC picture to evaluate the listening quality is because it corresponds well to how the ear works. Haas zone, spatial localization and all that stuff are concerned with the time/energy relation of sounds.


If this is once again read as the deluded ramblings of a religious follower, please give me a word and I'll drop it. I'm not doing this to convince anyone of a belief.