Proper Bass Redirection (and related question)

[Georg]

I have experimented a bit with bass redirection using EAPO.

The goal is to find out whether doing it via EAPO would have benefits (more flexible, better sound etc.) than activating bass redirection from the Soundblaster control panel.

Would this be a correct way to go about it???

`Preamp: 0 dB
Device: Speakers Creative SB Audigy 2 (WDM) {9f7619fd-9102-4e7d-bb8d-36525717c23d}
Copy: VSUB=0.3L+0.3R+0.3C+0.3LFE+0.3RL+0.3RR
Channel: L R C RL RR
Filter: ON HPQ Fc 70 Hz Q 0.6559
Filter: ON HP Fc 70 Hz
Copy: LFE=VSUB

Channel: LFE
Filter: ON LPQ Fc 120 Hz Q 0.8071
Filter: ON LP Fc 120 Hz
Preamp: 6.1 dB`

The above is some example code I found somewhere. The guy says it has an advantage because he is using a Highpass and a Lowpass, so one has more control over a possible sound "gap" between lows and his.

WHY is he always using two filters in a row for each??

Looking for example code/commands to do it "properly" for a 5.1 system. (If I don't have bass redirection on in any way, there is no sound from the sub).

(I have an analogue 5.1 system where the vendor is recommending a crossover f of 120hz in the Soundcard control panel. Huge sub, center and 4x small sats)

Related:

If I disable bass redirection in sound blaster control panel (which I assume I need to do for using bass redir in eapo?), what EXACTLY in Equalizer APO code does the redirection ???

Just applying the Highpass and Lowpass filters? How do the filters alone redirect the bass to the sub? This is what I don't understand.

Thanks!!

[Peter Verbeek]

Would this be a correct way to go about it???

It could be one way. I'm not sure what bass reflection is. These commands are taking the lower frequencies of the others channels and put it on the sub woofer. But if there's already sound coming from the sub woofer it gets overwritten. Other people have mixed this sub woofer sound with the sound of the other channels, for instance like this:

Copy: LFE=0.5*LFE+0.5*VSUB

Btw. Copying the sound to the subwoofer may already be done by the audio system, being the audio card/chip, the software audio driver and/or the hardware amplifier (if any connected to your pc), sometimes without one knowing. As you have switched off the one in the Soundblaster, there shouldn't be an issue. But if you notice strange sound effects from the subwoofer there might be something still enabled.

WHY is he always using two filters in a row for each??

To make the slope steeper so to get a clearer divisions between the low and high frequencies. How many filters is up to you. For example, I use up to 50 filters (in a row) for a brick wall filter in the Peace equalizer interface.

I assume the commands work on a 5.1 or 7.1 system. They seem so.

what EXACTLY in Equalizer APO code does the redirection ???

I don't know. Besides the common definition there probably are several other ones. So it's about what you need.