howlback wrote on Sun, 12 March 2006 00:18 |
Alex's original post mentions multiple formats. Some formats will apply a +10 dB in-band gain to the sub. Depending on you mixing process, you must keep this in mind, shouldn't you?
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Of course. Your monitor system must keep this in mind and be correctly aligned. But it's very important to not use the generic term "sub" when discussing this subject. Please use the term "point 1 channel" or "LFE" channel to refer to the EXTRA AND OPTIONAL channel that feeds the sub. This channel requires a +10 dB alignment in Dolby, DTS and to my knowledge any discrete 5.1 format EXCEPT SACD. HOWEVER, the regular "bass manager" (which is just a fancy word for a "crossover") should be aligned to flat, NOT +10 dB, and as such a 5.0 recording is totally legitimate and your bass should come out of that fine, partly directed to the subwoofer when the crossover says that the main speakers "need help".
Because of the incompatibility of the LFE channel in SACD with that in Dolby Digital, many practitioners of music surround for SACD have eschewed the LFE channel and are truly making 5.0 recordings, which have plenty of bass through the regular bass manager anyway, and will translate to any full range or properly crossed-over system, including Dolby Digital.
It's only when we venture into some types of music recordings where the extra headroom of the LFE channel becomes tempting. Such as hip hop, which eats up tremendous amounts of bass, or special effects, which is what the LFE channel (originally called the "boom channel") was invented for in the first place. Or when the producer insists he wants to hear something out of the subwoofer, even though the 5.0 is doing its job, so the engineer throws a little extra into the "Extra" channel. This is the dark side of the force, and guarantees some incompatibility issues, especially when converted to LtRt for broadcast, which does not include a "point 1" channel.
I think that in general, music producers should make a 5.0 recording first and if they really feel they should have a little "extra" and if they really feel the regular bass manager is not giving them the "punch" they want (which I highly doubt), then they should consider the LFE as an EXTRA and good luck. There are issues of phase (is your LFE connection IN PHASE and IN TIME with your regular bass manager? Will the bass that goes through the bass manager cancel or combine with the LFE?
Hope this helps,
BK