HomePod sound quality lower after update to Software version 15.6

I did a software update on my pair of 1st Generation HomePods and I noticed a significant change in the sound quality. The sound has a much higher pitch with a lot less bass! Very disappointing!! Did anyone else experience the issue? Is there a way to revert back to the previous firmware?

I just love my HomePods and even invested in a second one before Apple discontinued them. I hope this is not a trick from Apple to artificially reduce the sound quality of the 1st Gen HomePods to reduce the sound difference to the 2nd Gen HomePods that are expected to launch in the coming months!