When metal is cold, it shrinks. When metal is hot, it expands. So when it is cold why is our instruments flat?

it shrinks lol but with my trumpet i was always in tune as soon as i put it together it was weird and on rare occasions i wasnt Mr. green would go :asia, you sick today"?: lol

The speed of sound changes relative to temperature - warm air allows it to travel faster, and cold air makes it slower. Faster sound = faster waves = higher pitch = sharp. Slower sound = slower waves = lower pitch = flat.

Thank you, Alex. A friend of mine asked me this and we couldn't figure out a good answer.

Another thing people don't understand is that the metal expands and contracts to the center of itself- not the instrument. Imagine the instrument. It's essentially hollow so let's visualize an "O". When cold the metal contracts on the outside towards the inside but it also contracts on the inside toward the outside hence making the inside of the instrument where the air travels bigger. The bigger the inside of the instrument the lower it plays. The opposite happens when hot.

OK that's a little confusing. More simply when cold the instrument shrinks only on the outside and that doesn't matter. More importantly It expands on the inside which is where the sound vibrations bounce around.

So essentially cold instruments expand and hot instruments shrink.

yeah. Like when a sheet of metal is cold, both sides of the metal shrink, because the sides are moving toward the center of the sheet of metal. I understand what you're saying lol

Yes lol. It's hard to explain without visual cues

lol you actually did a good job describing it I understood almost immediately. I just had to think about it for a second.

You should have seen our tuning marks we had at BD!

I actually bought one of the Deg trumpets that was used by BD in 2001. It was neat to see those notches. I sold the horn a few years ago though.

Yeah my brass instructer told us about how you'd have the weather thing and then you'd just pull out or push in to a certain notch depending on the weather. Then you'd be in tune first try xD

Yeah. Every horn is tuned by Wayne to various weather degrees for like 50-110 or whatever.. he does this every time BD gets new horns. The tuning slide would be marked/indented with notches, so when warming up they would take the temp and say something like.. bari's 4, trumpets 3, tubas 5.. or whatever.. the colder it was the less notches were needed.. in Texas for example we would be at like 8 or 9 notches

Then we do individual tuning, but at least with notches.. it will put the horn at perfect tuning and then it will be adjusted to the person. It was great for last minute adjustments while waiting for a show to start since it's usually a big temperature change from warmups to the show since we typically go on very late.

That, plus everyone plays on the same mouthpiece and is taught to use the same techniques so everyone sounds the same - apparently it helps considering all of the Jim Ott awards they have

Yeah I always thought that was really cool. Freaking amazing idea

You know what else is a freaking amazing idea?

Not having band instruments in drum and bugle corps.

*universe explodes*