Tuning question

[scottw]

I have played my Mirafone 186 BBb for a number of years and the tuning slide needed only move a fraction of an inch either way for the ritual tuning of the ensemble on open Bb. Lately, my slide is almost fully extended to play to the tuner. I have made no repairs, I have not had an illness, no dental work, same blokepiece, noticed no lack of breath support---in short, I have made no changes and the horn hasn't had any work done on it. I notice no change of tone nor any intonation issues apart from the needed flat tuning.
I had a sonic cleaning done about a month ago, but I started noticing the problem before that. The horn is clean.
Does anyone have any ideas as to what may be causing this rather radical change?
Thanks!
Scottw

[TubaSailor]

When was the last time the valves were aligned? That can make a horn go sharp with a surprisingly small mis-alignment. (Yes, its a guess, that's all you can get without seeing the horn) FWIW --

[scottw]

Heck. We the TNFJ and Kangaroo Court don't have an answer for you, Scott.

All we will have will be a myriad of suggestions and guesses.

Here's the first one that you'll receive:

- Check your tuner. Is it set on A=440, or has that button been inadvertently tapped? If it is on A=440, try some new batteries. If all of that is a "go", borrow another tuner and set it up next to your own.

Suggestions and guesses are what I need until I figure this out. I found one band was using a tuner set on 435 and had them re-set it. Others have all led to the same flattened tuning with it set on 440.
Tuba Sailor: when the horn was cleaned last month, that alignment was part of the job. Like I said, this problem manifest itself before that.

[Bill Troiano]

Summer! I played an outdoor concert yesterday afternoon on LI. My slide almost fell out.

[Allen]

What is the temperature?

Summer! I played an outdoor concert yesterday afternoon on LI. My slide almost fell out.

Tuben asked a great question. It's really hard to keep the pitch down outdoors in Summer (and keep it up in Winter). I have observed bands tuning to A=440 in hot weather and then go sharp as soon as they start playing. I think it's better to just tune to a comfortable pitch -- sharp in hot weather, and flat in cold. Of course, it's up to the music director, even though he may not understand that the speed of sound (and therefore the resonant frequencies of wind instruments) changes with temperature.

Allen

[scottw]

What is the temperature?

The problem seems to occur in both an air conditioned room and outside in the heat, although in different amounts as you would expect. Tonight it was quite warm and I had to keep checking that the slide was still inserted as I pulled it out even further after I was warmed up. The Monday and Tuesday date was in A/C and it required a long pull for them, too. I can't figure it out.

[scottw]

Hay Scott,
Do yourself a favor; put a leash on it !
I don't mean something fancy, just a shoe lace will do.
If your slide does fall out, this will keep it from hitting the floor !
If you're good at knot tying, try to make a limiter / preventer.
Safety first !

Thanks for the advice, Brian, but, with my finger situation, a square knot is about the best I can do! A table saw is not your best friend, sometimes. Now you tell me about safety first!