Seeburg CV Extension Speaker Polarity

Hello,
For the first time ever, I am finally installing an extra two speakers
to my Seeburg VL. They are placed in another room, away from the
jukebox. I am using some generic Radio Shack 70 volt CV transformers,
wired to some Bose speakers.
What I was wondering is does anyone know what the polarity is between
the A tap and B tap on the amplifier that runs the extension
speakers. I have wired them both ways, and it sounds good each way.
But my imagination may be tricking me when I think I have slightly
better bass response when the positive lead to the transformers comes
from terminal A. Does anyone know for sure if A is positive, and
termonal B is negative?

Thanks much.
Bill in Tacoma WA