<html> <body> I agree. That's why whenever I can, I open the lid of the piano or harpsichord or whatever I'm tuning (at the university) a good while before I tune it! Thankfully, our conditions are fairly stable. But I've tuned in other conditions where the piano changes while I'm tuning after I've opened the lid. :-( Avery At 07:33 PM 3/25/04, you wrote: <blockquote type=cite class=cite cite>Greetings,            Yes, I have had the following experience: I was in piano tech school practicing tuning in a tuning booth (we used to call them tuning "caves"). Booth consisted of a sound proof glass windows floor to ceiling with a glass door. These booths are actually pianist practicing chambers used in conservatories, but our school used them for tuning practicing chambers.             I was practicing my tuning. I had been in the booth for 6 hours with a small ventilation fan on. As a green rookie, I couldn't figure out why I was having so much trouble getting the piano's octaves to match. Finally, I was "done". When I opened the door it was so much cooler and less humid in the hallway. My own breath had been making the humidity to rise all during that time. I took a break and went back into play the piano and sounded horrible! (like I hadn't tuned it at all) Here, the door being open during my 20 min break had equalized the humidity and temperature in the room and it had changed the tuning. Lesson learned.              Yes, it can happen. Jullia Gottchall, Reading, PA </blockquote></body> </html>