Bass leaves after amp warms up?

Are your speakers in phase? Are the cables in phase. Is there an inverting switch somewhere?

I didn't read through the entire thread but this is exactly what happened to a friend of mine. He opened the cabinets and found one of the woofers had the polarity reversed. Damnedest thing I ever heard, but it made sense after we put all of the clues together-our position in the room, the musical content.

It was one of those unexpected issues, if you know what I mean. He thought outside of the box (or inside, in this case). I would have never suspected the woofers came from the factory wired in reverse.

It was a simple case of wave cancellation.

(Sorry if this was discussed, I didn't feel like reading 10 pages of this thread).

Rich

Are your speakers in phase? Are the cables in phase. Is there an inverting switch somewhere
Yes/Yes/NO

Are you?

Are you?

Unnecessary. Comments like that are the reason I rarely look at this site.

BTW-Only one woofer was out of phase in my friend's system. The other speaker in the cabinet was in phase.

Why does it take time to perceive any difference? That could be due to musical content and aural acclimation. It took a while for me to notice the drop off at my friend's house depending on the musical mix, seating position, and volume level. Consider also that perfect wave cancellation can only occur with monaural material, so the musical mix plays a big factor in the listener's perception.

One of the reasons the old preamps had a mono switch was to help set the azimuth when mounting a phono cartridge. Wire one channel of the cartridge or speakers out of phase, place the preamp in mono and adjust the cartridge's azimuth till the bass response seemed minimal. This procedure works on the principle that wave cancellation can only occur when both channels are in phase, which can only occur when the cartridge is properly aligned. After the alignment procedure, the speaker or cartridge was restored to it's proper phase and the preamp was returned to stereo operation.

Sorry, couldn't help it. If it's any consolation, it wasn't meant for you. You should maybe read the whole thread. You might get a kick out of it:)