<font color='#000000'>Gene,
I read your "Bass Management, the Right Stuff" article and thought I would comment.
I think you're right about bass management not being implemented correctly on many HT processors, both prepros and receivers, that are on the market today, even those with selectable crossover frequencies.
From my persepective, the proper implementation of a LPF/HPF crossover combination should result in a smooth transition across the crossover boundary without serious peaks and dips at or on either side of the crossover boundary. This is easily accomplished with a symmetrical (LPF/HPF) 24dB/octave Linkwitz-Riley (L-R) crossover.
Actually the manufacturers typically provide a LPF that is designed as a 24dB/octave L-R, but it simply doesn't match with their misguided attempts at a HPF, which is unfortunately adopted from THX.
In addition to your LPF perspective, my beef is primarily with the implementation of the HPF. Almost all have a 12dB/octave 2nd order HPF.
Problems arise because the HT processor manufacturers (actually the DSP chip hardware vendor who supplies the software algorithm i.e., Cirrus, Motorola, others) assume you will have a speaker with a perfect 12dB/octave acoustical low frequency rolloff at the prescribed crossover frequency selected, usually 80Hz. Their misguided dream is that this 12dB/octave electrical + the speaker's 12dB/octave low frequency acoustical rolloff will sum to a 24dB/octave L-R HPF.
Unfortunately that dream couldn't be further from the truth. Many bass reflex speakers (most popular type these days)have something like an 18dB/octave low frequency rolloff or more at varying frequencies and are very unlikely to provide a satisfactory transition with any of the HPF crossover frequencies selected in the HT processor.
Typically, the only speakers that meet the 12dB/octave acoustic rolloff are sealed acoustic suspension speakers and THX rated speakers. Only the THX speakers start their 12dB/octave acoustic rolloff at 80Hz, sealed speakers can be at various frequencies, like 46Hz.
To sum it up, not a pretty picture
This is the primary reason I use the following:
large mains (towers -> -3dB @32Hz)
sub
small center
small surrounds
To get around this annoying HPF problem (I could never get a good match through any HT processor), I implement a time aligned 24dB/octave Linkwitz-Riley LPF/HPF active stereo crossover between the L&R mains and sub(s). In my case I use a crossover @60Hz, because it produces the least problems with my room modes and is about an octave above my mains -3dB of 32Hz.
This means in the speaker setup menu of my HT processor, I define
sub=No and have nothing plugged into the sub output on the HT processor. This means all LFE bass and all re-directed bass from small center and small surrounds is sent to the main L&R speakers+sub.
This provides well integrated low bass for both 2-channel and 5.1.
Any comments?</font>