Re: Digital Room "Correction"

Scott Dorsey wrote:

MD <imispgh@xxxxxxxxxxxx> wrote:

What sounded better about the non-processed system (by the way I have until recently been a believer in less is more. I tried the DSP and can't hear the negative. What do you think I am missing? is it possible the digital DSPs are better now and you need to update your experience?)


I doubt it, because the theory is still bad. Part of the issue is that
I tend to prefer no low end rather than bad and out of control low end.
And the dsp boxes didn't really do anything to help the out of control
low end.


On bumping up the low points. I agree it seems they move a bit - maybe 3 db - but then no matter how much you add you get nada (except for damaging your system I am sure). How would traps help this? Aren't these caused by certain frequencies bouncing off certain surfaces and canceling at my ear? Traps don't affect phase so where's the benefit?


Traps stop the standing wave problem in the first place, so you don't
have the peaks and nodes. If you can stop standing waves from forming,
most of the low frequency room issues go away.

Sit in a bathtub and wave your hand back and forth... you will find
that there are several different frequencies at which you can create
standing waves in the tub. That is, the wave reflects off the wall,
and returns in phase with the outgoing wave, so there are obvious peaks
and troughs that don't seem to move.

You can think of the reflection as being the result of an impedance
discontinuity between the water and the side of the tub. The side
of the tub is much more solid and less compliant than the water.

If you do this in an Olympic swimming pool, you can't make the same
thing happen, because the wave dies out by the time it gets to the
end of the pool. There are still frequencies at which it would occur,
it's just that they are very, very low and you'd have to excite it very strongly.

If you put a wooden box inside the pool, you'd get the same effect
with the water reflecting off the side of the box. BUT, if you put
a flexible box made of rubber, the wave would strike the box, the box
would excite the water outside, and the wave would continue to expand
without being reflected back. This is because the impedance of the rubber diaphragm becomes approximately the same as the water behind it.

The whole notion of the bass trap is that it's a gadget that provides
the same impedance as the free air, so the wave goes into it and is
not reflected back.
--scott
OK - thanks

Still looking for an answer to why the DSP is bad as opposed to not as good. What am I hearing or not hearing? What test can I run to tell? I can run sweeps, single tones, white noise and music. tell me what to A/B and I will try it. I am not sure how I got this label, on this thread, of being hard over on DSP - HOWEVER - if I experience something different I will have no problem admitting I was wrong.
.

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