Bass leaves after amp warms up?

It's called tonal balance and it's all about setting up a system to your liking. I mentioned this a couple of times on this thread and I think a couple of folks agree with me when I say your system is leaning out as it warms up. For the majority of systems this is a good thing because the system resolution is increased, distortion goes down and the system opens up. In your case you are already there when the system is cold and as it warms up the balance becomes too lean. As I mentioned in an earlier post on this thread, I have had a similar experience several years ago. I corrected the problem by changing the speakers. So, the system should not sound it's best when it is first turned on and improve as it warms up. In my opinion you need to change one or more components to get the desired sound. This is just my opinion.

I agree with Rrog. Its another way to look at what has been said regarding your specific amp/speaker match, ie the amp can drive the speakers, but not OPTIMALLY, which is what is required for good bass and dynamics. The upcoming amp change should be a big step in the right direction. We'll see...

I'm wating for confirmation from my dealer to send new amp.Obviously he would rather not.

I have analyzed and listened to "good" and "bad" recordings which Fishing created of Dawn's "Candida," in similar fashion to what I previously reported doing with a recording of "Respect Yourself."

It appears that the recordings of "Candida" were done with reasonable level settings, and with ALC and peak limiting properly disabled. I found that the "good" recording was about 0.4 or 0.5 db lower in both peak and rms volumes than the "bad" recording. Essentially the same 0.4 or 0.5 db difference existed between the volumes the two recordings when frequencies above 300 Hz were filtered out, and also between the volumes of the two recordings when frequencies below 300 Hz were filtered out.

The sound quality was generally very poor in both recordings. I suspect that the major reason for that was the low quality of the recorder's built-in mic. The single built-in mic, of course, also resulted in the sound being monophonic. Nevertheless, I sensed a VERY slight loss of definition in the bass on the "bad" recording. Not looseness, not weakness, just an almost unnoticeable loss of definition. Presumably the difference would have been much more apparent if the recorder and its built-in mic had not been in the loop.

Fishing also provided yesterday a "good" and "bad" re-recording of "Respect Yourself." I did not listen to those, but my software revealed nothing more than about 0.2 or 0.3 db differences in volume, frequency content above 300 Hz, and frequency content below 300 Hz. As with "Candida," the "bad" recording was the (VERY slightly) louder of the two.

Finally, today he provided a second set of re-recordings of "Respect Yourself." However, the recording level on these apparently was set too high, and the waveforms were clipped in numerous places, so I didn't do anything further with them.

FWIW.

Regards,
-- Al

Fishing's girlfriend hears the same differences. So there should be no doubt that its a real phenomena.