Use Subwoofer output

blitter2 · Jun 24, 2010, 07:42 PM

Hi.

I would please like to know when the "Use Subwoofer ouput" of Surrounder+ options has effect. I would like to enter an 80hz value using "Bass Redirection".

Does it only work when "Surround" option is ON?

I have "Toggle "Swap and Front Rear"" option enabled and I use the black jack of Live 5.1 for my 2.1 speakers.

Do I need to add anything to the DSP for it work?

Russ · Jun 25, 2010, 04:09 AM

I am not sure what you mean... If it is enabled, it is enabled.

If your source audio does not have an LFE channel, then you will not get any audio from the subwoofer output, except that which is the result of bass redirection (when bass redirection is enabled).

Note: Some speakers sets do their own bass redirection (built in crossover), in which case the kX setting will have little or no effect (if your speakers do not have a connection to the subwoofer output of the sound card, then your speakers do their own bass redirection (and 'Use Subwoofer Output' should be disabled, as the subwoofer output is not being used by your speaker set)).

WxMan1 · Jul 23, 2010, 11:30 AM

Its pretty much like Russ says. However, there is a plausible reason to use the sub-woofer output setting: the freq response of your speakers.

You could set bass-redirection in Surrounder+ to the low end frequency response of your speakers. That way you can minimize the amount of unuseable signal the internal crossover of your 2.1 speakers would have to handle.

That might be more important if you implement a set of small sized speakers for rear channel (surround) sound. Those speakers most likely would not have a freq response as low as your front speakers (lack of sub-woofer). By setting bass redirection on, all freq below the cut-off is stripped from front, rear and center channels and appears on the LFE port of Surrounder+.

You could set bass-redirection to the low end of the rear speakers (and the signal they receive would be within range of their frequency response). You could then shunt the signal on the LFE port to the front channels (but you'd have to filter it to discard whatever the front sub-woofer can't handle). OR, you could set the bass-redirection to the front speaker low end, filter the rear channels exclusively (and discard what's on the LFE entirely).

There's and additional advantage to doing that. By eliminating unwanted low frequency signal: the final stage opamp, i.e., mixer volume setting, has more headroom; the lowest frequencies use up most of the available power for any particular volume setting. The sound card outputs at most 1 w total, and probably 50% of that is utilized by amplification of freq below 100 Hz (and of that probably 75% is utilized by sound below 80Hz).

The operation of any amplifier introduces noise into the source its acting on. And so the ideal setting for both mixer and speaker volume control is about 50% (or less); you may be able to reduce the volume of either the mixer, your speakers (or perhaps both) somewhat and still retain the same apparent volume.

Jun 24, 2010, 07:42 PM	#1
blitter2 HardwareHeaven Lover Join Date: Sep 2008 Posts: 196 Rep Power: 26	Use Subwoofer output Hi. I would please like to know when the "Use Subwoofer ouput" of Surrounder+ options has effect. I would like to enter an 80hz value using "Bass Redirection". Does it only work when "Surround" option is ON? I have "Toggle "Swap and Front Rear"" option enabled and I use the black jack of Live 5.1 for my 2.1 speakers. Do I need to add anything to the DSP for it work? Last edited by blitter2; Jun 24, 2010 at 07:49 PM.

Jun 25, 2010, 04:09 AM	#2
Russ HardwareHeaven Extreme Member Join Date: Jan 2005 Posts: 5,563 Rep Power: 62	Re: Use Subwoofer output I am not sure what you mean... If it is enabled, it is enabled. If your source audio does not have an LFE channel, then you will not get any audio from the subwoofer output, except that which is the result of bass redirection (when bass redirection is enabled). Note: Some speakers sets do their own bass redirection (built in crossover), in which case the kX setting will have little or no effect (if your speakers do not have a connection to the subwoofer output of the sound card, then your speakers do their own bass redirection (and 'Use Subwoofer Output' should be disabled, as the subwoofer output is not being used by your speaker set)). Last edited by Russ; Jun 25, 2010 at 04:27 AM.

Jul 23, 2010, 11:30 AM	#3
WxMan1 HardwareHeaven Lover Join Date: Dec 2007 Posts: 221 Rep Power: 40	Re: Use Subwoofer output Its pretty much like Russ says. However, there is a plausible reason to use the sub-woofer output setting: the freq response of your speakers. You could set bass-redirection in Surrounder+ to the low end frequency response of your speakers. That way you can minimize the amount of unuseable signal the internal crossover of your 2.1 speakers would have to handle. That might be more important if you implement a set of small sized speakers for rear channel (surround) sound. Those speakers most likely would not have a freq response as low as your front speakers (lack of sub-woofer). By setting bass redirection on, all freq below the cut-off is stripped from front, rear and center channels and appears on the LFE port of Surrounder+. You could set bass-redirection to the low end of the rear speakers (and the signal they receive would be within range of their frequency response). You could then shunt the signal on the LFE port to the front channels (but you'd have to filter it to discard whatever the front sub-woofer can't handle). OR, you could set the bass-redirection to the front speaker low end, filter the rear channels exclusively (and discard what's on the LFE entirely). There's and additional advantage to doing that. By eliminating unwanted low frequency signal: the final stage opamp, i.e., mixer volume setting, has more headroom; the lowest frequencies use up most of the available power for any particular volume setting. The sound card outputs at most 1 w total, and probably 50% of that is utilized by amplification of freq below 100 Hz (and of that probably 75% is utilized by sound below 80Hz). The operation of any amplifier introduces noise into the source its acting on. And so the ideal setting for both mixer and speaker volume control is about 50% (or less); you may be able to reduce the volume of either the mixer, your speakers (or perhaps both) somewhat and still retain the same apparent volume.