Localized Bass?

[Steve81]

Say you have a 2.0 system. All bass goes to either the Left or Right channel. If the tone is above ~120Hz, you can determine if it's coming from the L or R. If it's below ~120Hz, you can't.

I've posted a little bit about the topic lately, so I'll toss in a couple pennies. As far as actual research on the topic, this paper is a biggie. Their finding was that with an XO at or below 120Hz (4th order filter), none of the listeners could detect the subwoofer with the samples used. What was more interesting is that half the users couldn't detect the subwoofer at the highest crossover frequency used (227Hz). The thing to keep in mind here is that real world content is a very different animal from playing 120Hz sine waves, which you may or may not be able to localize on their own.

Placement matters a great deal as well with respect to how high of an XO we can tolerate. If your subs are behind you for example, you'll have an easier time detecting the sub as the crossover frequency rises versus having your sub located near your L/R speakers.

As it relates to HT, here's something else to consider. Back in ye olden times, the LFE track was steeply filtered at 120Hz. Modern formats dedicate a full range channel to LFE, and leave the filtering to a low pass filter in the AVR. The practical effect of this switch is that the bandwidth a subwoofer is expected to reproduce for the LFE channel isn't markedly different from crossing your speakers over at 120Hz.

 

[AcuDefTechGuy]

What was more interesting is that half the users couldn't detect the subwoofer at the highest crossover frequency used (227Hz).

I can attest to that. When I raised the XO from 120 to 150Hz, I couldn't tell much of a difference.

 

[lsiberian]

One sidebar, although I can listen to music and movies at a volume which I perceive as being "right" from my 100 watt per channel amp powering mains and surround speakers, my sub demands a lot more power. I originally hooked it up to an amp producing 300 watts in bridged mode and still experienced clipping. Do you know what clipping sounds like from a 15 inch low frequency driver, it sounds like a sledge hammer banging on a steel pipe. Now, I have a 560 watt amp which so far allows for the highest volume level that I can stand without my ears bleeding.

This is true only if the subwoofers are more inefficent than woofers. The Dayton Reference line is an example of a very efficient line. So much so that I'm considering using them as a bottom in my next 3-way build.

 

[lsiberian]

I can attest to that. When I raised the XO from 120 to 150Hz, I couldn't tell much of a difference.

This applies to so many things in audio honestly.

 

[AcuDefTechGuy]

This applies to so many things in audio honestly.

You mean that every case is different and there is no such thing as one-size-fits-all ?