Bass leaves after amp warms up?

Fishing, You've had so much good advice here, I believe the solution lies within. I don't think you should make any major decisions (like new speakers) until you've measured the SPL.
On the subject of amps into PCs, just FYI, my Sunfire manual states "do not plug the amp into a power conditioner."

If the digital was unplugged, seems like we can rule that out as being a problem.

Go ahead and restore the system.

I realize I made a poor assumption. I would not have turned off the amplifier when messing with speaker cables. Most transistor amps don't care, and our amps don't care, so I always leave them on.

The fact that they are getting shut down is significant. As I mentioned earlier, the fact that messing with the cables gets a response is an important clue; turns out the amps were shut down during this time! They have become suspicious again.

The only bugaboo is that I think we did a test where the system was played until the bass dried up, then it was turned off for a while and restarted. The bass was still gone. But maybe it was not shut off long enough.

Next time the bass dries up, shut the entire stereo off for about an hour, then see how it sounds.

Next time the bass dries up, shut the entire stereo off for about an hour, then see how it sounds.
That's exactly what I will try
Thanks

Unable to regain the bliss sound at all today
I may be abusing the system in different ways
Considering virtual yacht raceing

Perhaps another clue:
Today it was suggested I play analog w/no digital
I took out all the cables and set it up but had a disappointing sound.
Took everything out tried again w/digital repluged in
Again,Unable to regain optimal sound even with one speaker.
Took everthing out again and reconnected just analog turntable.
This time the bass returned w/full dynamics (one speaker)
Question:
Could the way wires are falling on each other or something else during set up be causing this mess?
I will use this opportunity to listen G.Harrison Material world 180g vinyl
Hope at least to get through one album before vanishing act.
Thanks for everyone's patience with my illogical audio problem.