Surround Questions

[Matty Spindel]

Does a Pro Tools 5.1 surround session automatically take care of the bass management part of the mix? Sending the low end frequencies to the LFE track (track 6)?

[CLee]

no-
bass management is a function of your MONITORING system. the LEF track is a low frequenct EFFECTS track and should only contain effects, not the LF content of the entire mix. If someone has a PLAYBACK system with a subwoffer and bass management it will redirect the low frequency info from the 2 or 5 other speakers to the sub. remember, if you put something on a LFE track and someone has no sub they may not hear it, a mix could easily go out as a 5.1 mix with an empty LFE track.

are you doing music or post? I do mostly post so i dont know what music folks are doing but it would be interesting to know

[Matty Spindel]

Thank you so much for your expertise. But, I am doing a music mix in surround. Not a film or television post project. Does that mean that I am soley responsible for what ends up on the LFE track. Or does the "bass management" ALSO add low end information to that track as well?

[CLee]

its a little unclear what your asking.

the LFE track is part of the recording process, which doesn't involve bass management. think of bass management as a crossover in your playback system. the low frequency info below 125 HZ (or somewhere around there) is REDIRECTED from the satelite speakers to a sub. so what the sub reproduces is the LFE track plus the lows from the other 5 speakers. bass management only happens in playback systems designed with that feature. other systems play back full spectrum from the 5 speakers.

when recording you direct full spectrum to all 5 speakers. if you have an effect you want only to play from the sub you put it on the LFE track.

i dont do music so i dont know what people are putting on the LFE track. maybe some music engineers could jump in?

[Matty Spindel]

Again, thank you so much for your answers. I'm sorry about the clarity of my questions. Let me see if I can make myself a little clearer. Here's a scenario: I have a bass drum that already exsists in a Pro Tools 5.1 surround session. I decide to pan it to tracks 1 and 3 (left front and right front). In playback (monitoring) does P.T. automatcally send the low frequencies of that bass drum to the LFE track (track 6). Or do I have to add as much of the LFE send (on each fader) as I deem satisfactory? I certainly hope that clears up my question for you. Again, thanks alot.

[CLee]

no- pro tools will NOT send any of the kick drum to the LFE track. and it shouln't. your monitoring system may- if it has bass management.

A chain: recording and mixing- what goes to tape. anything going to L & R (like your kick drum) should be sent only to those speakers (any divergence aside). maybe you are sending bass guitar to center, that should also go only to center. your master, which will then get dolby stereo or AC3 encoding will have no bass or kick info on the LFE track.

B chain: your monitoring system (and also consumer playback). if you DO have bass management the crossovers see info in the L&R from your kick below about 125HZ and redirect that to the sub, it doesnt play from the L&R speakers. the same would go for the bass git in center. if you DO NOT have bass management the kick and bass would playback full range from LCR and the sub would sit and do nothing.

that may not seem right at first but that is the way it should be. if a consumer has no sub and you send your los to the LFE track they may not hear that info at all. if you send it to both the LFE and mains someone with bass management will hear way to much.

hope that helps clear it up. like i said, i dont do much music but thats how its done in post.

BTW i hope i got my A&B chains strait!