Hi,

My hi-fi sounds great sometimes and not others. I am told that it needs an hour's warm-up
and this could fit with the times it has sounded good. For example, great one evening but
poor the next morning. I leave the electronics on but not playing.

Is there a CD that can be played to loosen the system up? I suspect the speakers most.
Bass extension is particularly absent at times. Any suggestions as to whether playing a
very low frequency sine wave or similar could do the trick?

--
TIA,
James