Charlie, by channels I mean tracks. Right now you have 5 tracks open to either MIDI or RTs while the rest of the tracks are dedicated to melodist, harmony, MIDI guitar etc. I wish is to open all tracks to the user.
That's the way I was interpreting your post but my knowledge base of midi is not that deep but that's how the Yamaha workstation multitrack recorder worked. Normally, track 10 was used for drums, track 1 for piano, track 2 for bass, track 4 for melody and track 7,8 for guitars
The multitrack operation of BIAB is similar to the Tascam DP series of multitrack recorders. I have used Tascam Portastudios for many years and for most of those years, tracks were limited to 4 or 8 tracks and bouncing was essential. With digital recording and hard disks, the track count increased to 24/32 actual tracks but the total number of tracks using virtual tracks and bouncing is practically limitless.
The Tascam DP008 pocketstudio can record mono or stereo tracks and is marketed as a six track model, (2 mono tracks and 2 stereo tracks), it is simply an upgrade of an earlier model DP004 which had 4 mono tracks. Pocketstudios and Portastudios can record two tracks simultaneously. But by bouncing tracks (digitally) to a virtual track, you can record all 4 tracks, using all of the available inputs, then bounce these four onto a single or if stereo, to two tracks into a virtual track that replaces one or two (stereo) recorded physical tracks. Continuing to follow those steps, you can record an unlimited number of total tracks bouncing the four available tracks in various combinations. Being digital, there is no loss of quality in the rendered recording. I have posted Tascam Dp multitrack examples in another thread here on the forum and you can hear how well they record for yourself.
Biab Features of the audio track and Performance Tracks allow Biab to record and save tracks in a very similar manner to the Tascam DP series recorder. In other words, nearly an unlimited number of tracks can be generated, mixed and bounced....
The feature of being able to record multiple instruments on a single track add to the recording versatility of Biab. (Punch in/out)
I will give an example of multitrack recording beyond the eight visible Biab tracks but make note, there are many variations of this technique and this is only limited by the requirements of the song and your imagination. You may already be aware of this technique but I don't recall ever seeing it discussed in depth here on the forum.
After you've completed a chord chart - by inputting yourself, import a midi or a chart generated via the ACW, or just open any existing sgu file.
Select a style. I chose OUTRAGE.STY a five track Realstyle for this example.
Pan and mix the tracks. You can add additional tracks to the audio, Melody and Soloist tracks if desired.
Render all the tracks to a WAV audio file to your desktop. According to your needs, you may decide to render just a few tracks; for instance, drums and bass and a loop track...
Import the rendered audio file to the Audio Track. It should default to 1.1.0 and sync with the existing tracks. Use the Audio Editor to sync the tracks if necessary. I haven't had to do this so far.
Select Audio/Move Audio to Performance Track
A window will open to allow you to select any track other than the audio track. You will be prompted to save the file if it hasn't been saved at this point.
Since my song normally will only have one bass or drum track, I select one of these tracks to move the Performance track to. It will be a stereo track.
At this point, all of the remaining tracks including the audio track are available to select styles, Realtracks, midi tracks, Supermidi or audio and free to add additional tracks to be rendered to your song.
Continue rendering the new generated tracks over the existing chord chart. MUTE the performance track(s) unless it's desired to be included in the bounce to a new audio file to be exported and reimported back into the audio file and converted and moved to another track as a performance track.
This process can be repeated many times without loss of audio quality. You can use F5 to have newly generated tracks to contain multiple instruments. A very complex arrangement can quickly be generated in this manner and never leave the Biab program. This technique works with both PC and Mac versions. Effects and VST's can be applied. Performance group tracks can be rendered together to form larger group performance tracks. Although only a single audio track can be recorded at once, using this method allows for multiple audio tracks such as vocals and additional backing tracks to be recorded into Biab mixed, rendered, exported and reimported back to the audio track, made into a performance track and moved to another track.
A very powerful benefit of doing this in Biab rather than moving to RealBand is the Stylepicker for Biab is different than the Stylepicker in RB. The RB Stylepicker does not contain the feature to audition styles over your chord progression but that feature is available in Biab Stylepicker. A style can sound dramatically different played over your chord progression from how it sounds playing the demo. Some RealStyles contain up to five tracks of RealTracks so you can also audition hundreds of Rt's in just minutes versus the time required to do the same in RB.
You may already be aware of this technique but as I've noted, I've not seen it discussed in depth here on the forum before. Hopefully I've described the process with enough clarity you can experiment with the techniques and find some use from it.