Thiel Owners

Good to see you guys-

Yes, A/C conditioning is dependent upon your locale. Once your gear is truly broken-in and burned-in, every day will be a "Good Ear Day!"

Happy Listening!

Dave-

living in the vicinity of one of our major U.S. cities, you and others will certainly experience this phenomenon.  Airports are to cite and blame as well due to radar / signal blocking capabilities and daily operating RF/EMI
functions.  Another consideration is living in a certain radius of Military bases/depots/annexes.

Otherwise, radiation, is a prime culprit- computers, hard phone lines, cable lines, cell phones, smart phones, satellite phones...etc.

Happy Listening!

@robinbarbour
Have you considered changes in temperature, humidity and atmospheric pressure affecting the sound waves?  It's measurable and audible.  Could be that simple.

Good to see your return- saffron_boots

excellent points and observations.  Happy Listening!