Akai MG614 sync mux?

[poofygoof]

has anybody else been curious about the mux circuitry for tape sync on the MG614? while you are obviously free to dedicate a full track to sync, it has FM modulation and demodulation circuitry that lets you put a sync signal on a track and record low-pass filtered audio at the same time.  I haven't seen this in other cassette multitracks. the low-pass for the audio is pretty severe, (10kHz IIRC,) but might be OK for some bass or kick drums?  (I'm not enough of an electronics guy to know what the bandwidth is for the FM-encoded signal.)

I can't see how it would be possible to re-record the sync/bass track once it's laid down, meaning you can't bounce tracks to it, and it makes no sense to bounce from it (since you can't reuse the track). I also wonder what sync signals it is compatible with, (would it work with linear SMPTE, for instance,) but it seems a clever idea.

the bigger MG multitracks (like the MG1212 or MG1214) with the proprietary cartridges have a dedicated sync track, so it doesn't seem this technology survived in other Akai products.