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Old 19th August 2019
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boggy's Avatar

Hello everybody,

I already gave my best answer to OP, and I will add that not all the walls, are (stiff and heavy) WALLS for LF working region, as people mostly assume here, so there must be a caution when making conclusions about S.B.I.R. for other visitors of this forum.

Somewhere you will find brickwall, somewhere concrete wall, resonant or dampened, plastered or not, or there will be just drywall construction with some "insulation" inside, or no "insulation" at all.

These boundaries are not the same from loudspeaker/listener perspective, even with thick, full acoustic treatment... anomalies (if they exist) cannot be "hidden".

Measurements, listening and finding best loudspeaker/listener position is still applicable to many real situations, especially to these unpredictable rooms behavior, when we adapt exising room, dimensions are not ideal, boundaries materials too, ... in short, when and where "rules" doesn't apply.

Originally Posted by Adhoc View Post
...EQ:ing is not an option to prevent SBIR. SBIR occurs due reflections of sound which has already left the speaker and you cannot stop the sound electronically after it has already left the speaker towards a reflective object. (I think = do not know for certain, John PM on this forum (the author of REW) wrote you can prevent / lessen it with EQ but it was not an easy procedure, so in practice not manageable.)
Of course, I agree. But if you "soften" reflections with carefully designed LF treatment of main boundaries (not floor), you can take back (some) control with EQ, after finding best possible position during loudspeaker/listener placement.

It is also needed to remember that EQ filter applied to loudspeaker response in carefully treated room, may be reasonable or may be not. Because that, it is needed to "measure" and discuss influence, of each filter applied, with end user/listener.
Yes It may be a long process... and if someone has listening skills and, even better, know what he want to hear... it may not be Mission:Impossible.

As @ Northward noted in his post, about 100% predictable response (in slightly different context), it is important to know, when you adapt room which you have, and not room which you do not have, you must include lesser predictability of results and be prepared for improvisation...

Then, finding loudspeaker/listener best position, really IS an improvisation, in all these non-predictable rooms.

Last edited by boggy; 20th August 2019 at 05:42 PM..