Going down in frequency:

A 27.5
G 24.5
F 21.83
E 20.6
D 18.35
C 16.35*

*This is a 32' C pipe of a pipe organ, and none of these notes are associated with music, other than a pipe organ that's that big, so accuracy down in this realm is of no concern to me.

That's why I use the standard 1/12th octave sine wave disc for the LFE sub.

The RB, or music sub, was designed to play flat to 30 (-3dB@25, and with a second order roll off from there), which is at the actual low end of instruments, and to have extremely low group delay (5ms@30Hz) and have immense headroom for transients and to have adjustable damping (Q of .5 to 1.0) for personal taste.

I've been saying this for 2 years now, largely onto deaf ears, but summing the LFE channel with the redirected bass is the culprit in FR problems at the listening position.

When you design a sub that has to withstand the signal that all redirected bass+LFE+10 represents, you have a sub that's capable of subsonic reproduction at high levels.

Many of your favorite music discs were never monitored with subsonic capability and, therefore, include subsonic artifacts (yes, digital sources too) that a good music sub will discard, without the use of a subsonic HP filter, which causes phase shift problems that need adjustment when the filter is engaged.

A good RB+LFE+10 sub will not only reproduce those artifacts, the room it's in will grossly distort them as much as double or more. It's also almost always a ported or passive radiator design (and is BIG), and increasing order of subwoofer box design equals increasing group delay.

To those who argue that 20-30ms of time smear isn't audible down low, or if you tune a 4th or 6th order sub low enough, the group delay spike moves into the inaudible frequency range, I say..."Lay $1,000 on the table and subject me to a blind test, if I guess right every time, I get the dough."

The whole 'music vs movie' sub thing pretty much proves my theory. Contrary to lots of manufacturers claims, no one sub design does both exceptionally well. So, the answer to that is simple...have one of each kind of sub.

A smaller, sealed, high-quality sub that's flat to 25 Hz allows for it to be so much easier to reintegrate the redirected bass back into the soundfield from which it was taken, in any room, than a big, subsonic 'summed, single digital signal' subwoofer.

The LFE sub can be run hot, is silent during stereo playback, can be governed by any filter corner and slope, without affecting the RB sub and can be attenuated or even shut off when playing MC audio sources.

Otherwise, there is no tweaking required when switching back and forth from movies to music.

Keep in mind that movie discs are soon to have lossless soundtracks with much more headroom and accuracy of the signal, making multiple subs an even better idea.

Just an opinion.