Hi.
Congrats on the 464 acquisition.
Looks like mixer channels 5~12 are just 4 line level mono or stereo inputs. You would use typically use them for mixing in stereo line-level sources like keyboards or drum machines OR returns from effects devices.
All the mixer inputs can be tracked to the 4 tape tracks. If you source a tape track to the L-R buss (tracks 1 and 3 can source the L buss, tracks 2 and 4 can source the R buss) then it is going to record anything you have routed to the L or R buss. This can be done with mixer channels 1~8 by using the pan knobs. If you use both the L and R input jacks on channels 5~8 then you'd keep the pan knob centered. Looks like channels 9~12 have no pan knob (is that right? I don't own a 464 but do own a 424 so I'm looking at little pictures of the 464 control surface off of Goggle Images...) so those are really assumed to be used for stereo line-level sources only...now, I believe there are switches right at the top of channels 5~12 that say "L-R OFF MON"...is that right? If you have it set to the left position (L-R) then that input is sent to the L-R buss and is available to the recorder if a track is switched to L BUSS or R BUSS (depending on whether we are talking about tracks 1 and 3 or tracks 2 and 4). OFF means just that...that input goes nowhere...kind of like a mute function. switch it to MON and you can hear those inputs in your monitor buss but they won't be available to the recorder which is nice if you are just tracking along with a sequencer or something or want to monitor effects while tracking but track dry and you want to hear it through the mixer but not record it.
Mixer channels 1~4 are available to the recorder 2 different ways. They are available to the recorder the same as 5~12 with the L BUSS and R BUSS enable and then you can direct to either the L or R buss (or both) using the PAN knob, -OR-, the second way, using the DIRECT setting you asked about. When a tape track is record enabled to the DIRECT setting, it will record whatever is on the corresponding mixer channel (i.e. tape track 1 will record mixer channel 1, track 2 mixer channel 2 and so on through track 4 and mixer channel 4).
TAPE CUE is used just for monitoring tape tracks while overdubbing...a basic mono tape cue, so yes there is a way to mix the tape tracks through the full mixer strip. Look at the top of mixer channels 1~4. The switches there should be labeled something like "MIC/LINE OFF TAPE". MIC/LINE sets the channels strip to "listen" to whatever is connected to the MIC or LINE input jack, OFF is just like it is with channels 5~12...the channel goes nowhere, and TAPE sets the channel strip to "listen" to the corresponding tape track...channel 1 sources tape track 1, channel 2 track to and so on through channel 4 and track 4. That way you can mix down your 4 tape tracks through the full channel strip with EQ and EFFects sends and such. You also can have effect returns connected to 5~12 and other line sources and mix those in to your stereo mix when mixing down by routing them to the L-R BUSS...the tape mix and those other inputs routed to the L-R BUSS will be all summed to the master fader and then on to the main output jacks which would be connected to your 2-track master recorder.
Best way to bounce...let's say you have material on tracks 1~3 and you want to bounce that all to track 4. You would source mixer channels 1~3 to TAPE, get your levels set where you want and EQ and such, set the PAN knob fully clockwise to hard R, and then record enable track 4 to the R BUSS. Does that make sense? Same thing if you wanted to bounce tracks 1, 2 and 4 for instance to track 3, you'd just source channels 1, 2 and 4 to TAPE and set the PAN knobs to the channels fully counter-clockwise to hard L and record enable track 3 to the L BUSS.
Hope that is not too confusing and that it helps.
