Bass leaves after amp warms up?

do you have a CD with frequency-specific tones you can use,like one of the old Stereophile Test CDs? One-third

Yes I have Stereophile test cd #3

I will get a SPL soon as possible

Also I can record from my listeing positin when the
Problem is and is not present

I will upload on my computer & be able to send a copy by email

OK I recorded a Song "Respect yourself" Staple Singers w/The bass the way it sounds right to me and with the bass not the same to me
I can send in email and will open in your real player
Anyone would like to hear the two versions please mention your email addresss
Thanks
AP

Anyone would like to hear the two versions please mention your email addresss

I don't think that A'gon allows posting or communication of email addresses, and the onsite messaging system can't accommodate attachments. Can you upload it to a web hosting or file sharing service and provide a link?

Regards,
-- Al

Fishing, When you run your tests with the SPL meter, set up as Al suggested and using your test disc, be sure to chart your results on a graph. This will allow you to have visual evidence of the changes you experience and will serve as an easy reference if you try moving your listening chair or speakers which you should also note on your graph. This will serve you well on your current problem, but it will also serve as a base in the future should your start to move your stuff about. It's a bit tedious, but considering all of your efforts so far it's worth while to solve or rule out possible issues.

Also, room temps can affect sound levels at some frequencies somewhat so I would note the room temp when the tests are made so you can compare them to later tests at different temps.

Another thing you can do is to disconnect one speaker. Then set up your mic/SPL meter about 3ft from the center of the connected speaker. Then run your test and chart it. Then disconnect that speaker, connect the other speaker and run the same test. This will help you rule out problems with the cross over in either of the speakers because they won't measure the same. (I once had a new pair of speakers with a bass problem in one speaker created by the manufacturer's mis-wiring a cross over. One speaker was flat to 32hz, the other rolled off starting at 100hz.)

Hope that helps a bit.