If I add trumpet 2 a guitar band,wouldnt it be easyier if guitar tuned down a1/2 step 2 E flat?

the trumpet is tuned B flat,I cant change that.But you could tune the guitar down a half step?Because E flat goes with B flat. OK Good Luck coumminity.

No, the trumpeter can play along with any song in any key.

Just because the "open note" when blowing in the horn is Bb, doesn't mean that trumpet needs to play in that key or any others is particular. Like any other instrument, being able to play in a certain key has much mostly to do with the musician knowing HOW to play in that key (basic theory of knowing which sharps or flats are in that key). Sure, some keys may be a little easier for certain instruments, but I wouldn't see this as a roadblock.

it'd be a good idea but it's not really necessary, i mean if you want it to all sound kinda blended together than tune it down, if you want there to be an obvious difference in tone then keep the guitar in standard, either way it's really fine it just depends on how you want it to sound

That's an interesting idea, not entirely necessary, but interesting. just be VERY careful. it would be rather embarrassing to have a mistake in tuning and not realize it until you're half-way into a performance. It all depends on the experience and preference of the players and how much trouble you want to go through to re-write everything. Remember, it's your music. it doesn't have to always be standard, just as long as it sounds good.

The trumpet is not TUNED to Bb - it is keyed to Bb, meaning that when the concert-keyed instruments play Bb, the trumpet plays C. Any trumpeter worth his salt can transpose to whatever concert key you play. I play Tenor Sax, so I transpose to Bb keying all the time.

In most guitar bands (assuming you are playing rock or blues), most songs are in the key of E, A, or G. So, for the key of E, trumpet plays F#, A is B and G is A.

Why not buy a guitar synth, then you have all the benefits of a trumpet player without the expense.