In article , prograde49
@hotmail.com says...

I want to tape some cable programs for a friend who does not have HBO
& mail them the cassettes. My VCR supports SP, LP & SLP. Their VCR
supports SP & EP. I see on the tape box (T-160) that both EP & SLP
provide 8 hours of recording. This is the speed I generally use and
prefer due to the recording length, but the last time I prepared a
tape for the VCR in question, the audio was very muffled. I tried the
tape on another VCR in the area, it too was muffled.

SLP = EP = 6 hour. Same speed just different terminology.
More likely you have a stero vs. mono compatibility problem.
Two skinny heads playing one wide track = no problem.
Wide head playing two competing skinny tracks plus dead band
between = not so good.
Other possibilities: weak or incorrect recording bias, head/
tape path alignment problem.