Originally Posted by sdurani
The "penalty" he's talking about seems to be output, though he admits that it will "even out the room response". Which is not quite the "its hard to get them set up right" comment you attributed to him earlier.
The quality vs quantity trade-off comes down to personal preference, so you have to decide whether you want smoother bass or louder bass.
Yes, my main consideration is output. Mid wall placement is good to deal with room mode. But it comes with a price, the output is 3-5db less than a corner loaded sub. Our standard recommendation for sub placement is corner. There are some subs that are borderline boomy. Corner placement will further exacerbate the problem. Mid wall placment can sound better because it takes some energy away from the bottom end to make it sound less boomy. The sound quality from the subs does not change because we change placement. On the other hand, our subs are more articulate and we can take advantage of corner loading. In addition, very often the corner is also close to the front speakers, which makes the time alignment and coherence better than say mid wall placement of side walls.
The room mode is a problem with static/stationary signals. The so-called peak in frequency domain is not really a peak, instead, it is a ring that spreads out in time domain. When you have, say, a contant 20hz, the reverberation accumulates and that is how you get the peak and null. But when the signal is constantly changing, the reverberation is often heard later when the speaker signal already changes to a different frequency. The reverberation of the latter will arrive even later. So at any given moment, what we hear is not same as FFT (which is the mathematics giving us the frequency response). A lot of FFT are looking at 100ms or even longer time window. A better metric should really be a windowed FFT, in which we only look at say 30ms at a time. Why 30ms, that is about the time we cannot differentiate the signal arrival time.
-Edited by Rythmik - 8/28/13 at 6:58am