🚀 go-pugleaf

I have a tiny, hand-held Sony microcassette recorder that has the option
of two tape speeds: 1.2 cm/sec and 2.4 cm.sec.  The sound quality is very
good even on the slower speed, and as I use it for voice recording only,
I would like to be able to slow down the mechanism to say, 0.6 cm/sec?
or some slower speed in order to get a longer recording time per cassette.
Is this possible?  It runs on 3 VDC.  I was wondering how the motor speed
is halved.  Is it a simple supply voltage cut?  Obviously the electronics
still needs 3 VDC, but could I cut in half the motor supply voltage and
double my recording time?  I don't care about wow and flutter.
All it needs to be is understandable, not "hi-fi".
Any insights on this would be appreciated.
Thanks.
--keith