Why do subs sound bloated or slow?

"There's an element of "When did you stop beating your wife?" to this discussion. It starts with the presumption of guilt (for subwoofers) and asks for proof of innocence."

Yes, good point!

Subs are not more problematic in general than most other ingredients used to produce good sound.

They can be done well or not just as easily.

One more thought re: cbw's observation that his subs are sentitive to movements of 1 inch. That would be a little extreme IME, but his point is taken. Small movements of the source of deep bass can audibly affect the perceived sound, but once again I'd be inclined to attribute this to room interactions (rather than increased group delay) and note that it, too, is not unique to subwoofers.

Marty

I should note that I didn't mean to be dismissive of Bryon's initial observation which (I assume) is paraphrased as:

"If you're gonna fix the room induced FR problems by separating the source of bass from the rest of the spectrum and moving it closer to the wall (in the form of a sub), you're gonna induce time domain issues."

Assuming that this was the original point (and I apologize if I've mischaracterized it), the issue I have lies not in the general idea, but in the use of the terms "slow", "bloated", and "zero sum".

Even if you concede that gains in FR come at the expense of issue in the time domain (and those using even cheap HTRs needn't necessarily concede this as these units generally compensate electrically for the difference in physical distance), that does not mean that these issues:

A: will be perceived as slow and bloated for time domain problems

and/or

B: will audibly cancel each other out (zero sum).

Indeed, I personally find the former orders of magnitude more audibly troubling than the latter. And I also believe that any audible effects in the time domain can be largely mitigated through careful set-up. In sum, I'd say that, in a well set-up subwoofer system, the benefits in FR obliterate any costs in the time domain.

But, as noted, that is me, personally, and I understand that others may reach a different conclusion.

Marty

Marty, I don't think the effect I described can be reduced to room interaction because, as I said in my earlier post, I can achieve the same result by adjusting the delay of the mains relative to the subs without physically moving anything.

Stringreen, sub level is certainly important for proper integration, but turning down the level on a misaligned sub won't solve the problem, it will just make it less noticeable (along with the bass).

Shadorne, I disagree "that you can't perceive accurately what is happening to the bass response except by what it 'masks' in the higher frequencies." If you consider a single frequency around the crossover frequency (say, 80 Hz), it is being played by both the mains and the sub(s). Those outputs will either sum properly, or not, and you can easily hear very small changes in delay. (As an experiment, try playing a constant tone and turning the phase knob on a properly-aligned sub while watching an SPL meter.)

But real signals are the sum of a wide range of frequencies, and the overlap between subs and mains is also across a range of frequencies. Properly aligned, the waveforms will sum together properly, but when misaligned they will smear out the low-frequency information. The effect is plainly audible, and can't be attributed solely to masking.