"Yes, this exactly is the purpose of B-2. Many users buy it for the variable SUBSONIC only. Every subwoofer will sound better when you filter iddle / blind power = what your amp produces but your speaker cannnot deliver. Very important for bass reflex as well: below the port tuning frequency the response curves goes down sharply - but the amp is still pumping lower frequency power into the speaker voice coil which heats up resulting in thermal compresion (higher impedance of hot coils) and eventually burning. Many use it for smaller speakers like 3-5" full range. These speakers are good for one point source but the X-max. is short = very limited bass capability. If you set the SUBCSONIC just as high as you hear slightly less bass than this is the right setting where the speaker is limited and should be relaxed from those iddle power. This will also keep yur amp cooler or you have more reserve to have more power reserve for the audible range. Do not underestimate the variable / parametric BOOST LEVEL. You can extend bass about 1/2 octave. The trick is a well set combination with SUBSONIC. .
So... the B2 has:
1. A user adjustable SSF that can go as low as 10Hz
2. A user adjustable one band, one octive parametric EQ filter that can boost the signal up to 12dB
3. A gain adjustment knob that can decrease gain, but also increase it up to 10v
Sonnie has a B2 that he uses and has found that the SSF when set to 10Hz actually performs like it is set to 12Hz. That tells me this device has a lot of potential, but is not as accurate as it could be. To get around this, all one has to do is to run closed curcuit sweeps with REW to see what the various adjustments really do. Considering what we already do with REW when setting up our BFDs, that should be pretty simple. Then we modify our SSF and low frequency boost settings based on what WinISD recommends for our subwoofers given how many watts we send each drivers.
Based on my needs and what I've heard so far, I went ahead and ordered a B2 for my HT. It will take a while to get it set up (I recently moved), but I'll report back once my HT is properly installed. This device could work really well for sealed subs, IB subs, ported subs (LLT or otherwise) and large main speakers alike.
Read more:
http://www.hometheatershack.com/forums/ ... z2VpdvmU3D"