quick question

[mdocod]

So many rooms, so many variables.

Seriously speaking, I have personally experienced some pretty dramatic (very noticeable) bass loss in various points in a room depending on the drivers/boxes/placement and room characteristics combined with my position in the room. (My position in the room being the most significant player actually)

In the real world, we deal with rooms that may share an open stairwell or a shared open space with a kitchen or some such. In these real world scenarios, you should expect some major variations all through range of listening. You may be focusing on bass, but, in reality, there are probably a lot more dips and rises through the range than you may realize.

Fact is, it's easy to "focus" in on bass response because it can effect so much more than just the ear drums. As a result, you may find yourself moving about a room, "feeling" less bass in various places, while, you are simultaneously walking in and out of various "lobes" of intensity for many other frequency ranges while not noticing. The difference is, that when you are more focused on the bass range, your mind basically "fills in" the gaps of sound levels in higher frequencies, because the mind sort of "knows" what it is supposed to expect in those more normal listening ranges.

The mind will play tricks, you sort of intuitively know the expected output, so even if you are in a dip in the lobing at higher hz, the mind will say "it's over there and still exists just as loud" and thus you interpret it as being as loud.

Crazy eh?

Sorry to go all complication on the factor here.

The answer is yesyesyesnonononoyesnoyesnoyesno

[weltersys]

Originally Posted by Professor smith

Why then is it that in my room all the corners I've tried don't give me deep low bass? The best position is about half way along one wall. This contradicts the usual advice of corner placement.

What position would give the deepest bass in a cubic shaped room?

The "deepest bass" position would be dependent on room dimensions, regardless of room shape, and would depend on your listening position in the room in relation to the woofer location.

Predictions of gain going from full to 1/2 space to 1/4 space to 1/8 space are predicated on an infinite space as occurs outdoors away from boundaries.
In room response is quite different when the wavelength is large compared to the boundaries.

A 20 Hz wavelength is about 56 feet, a 40 Hz wavelength is 28 feet, a 80 hz wavelength 14 feet.
In a room with dimensions small compared to these lengths, the initial wave combines with the reflected wave in various combinations resulting in an additive peak (in phase) or more or less subtractive (out of phase) dip or null.

The distribution of the peaks and nulls (room modes) are dependent on room shape, dimensions, speaker location and frequency.

The distribution is so complicated that computer programs presently only model the modal range in 2 dimensions, but room modes are 3 dimensional.

Art