How to be in tune quickly?

[yufei]

I have this bad problem of going too sharp or too flat on my brass instrument (horn) how do you overcome it? 

[pianistimo]

why are you asking piano players?  i'd guess that if you blow less you'll be flatter and if you blow harder it will be sharper.  but, how am i supposed to know.  maybe your ambusher (sp?) has to be changed.

[cosine]

maybe your ambusher (sp?) has to be changed.

Hehe.. close pianistimo, it's embouchure. It's pronounced almost like "ambusher," "ombusher" is the pronounciation.

Now, about yudei's problem:

What brass instrument do you play? I hear people refer to their brass instrument as "horn" all the time; do you actually mean French horn, or some other brass instrument? Where do you go sharp or flat? Only on certain notes, or it is just randomly? Are all of the slides pulled out or pushed in the correct length? That greatly affects tuning (because that's how you tune a brass instrument  ). When you go sharp or flat, are you changing anything on how you play? Embouchure, breath support, the vibration of your lips?

The more info you can post the better. Or you could just ask you teacher or band director. 

[quantum]

Have you tried playing on a different instrument?  Sometimes cheaper student model instruments are inconsistent with being in tune with itself.  On that note, you may want a tech to look at your instrument to confirm this. 

The more details of your problem, the more people can help.  For example provide circumstances in where this frequently occurs.  What ranges in the instrument, etc. 

[timothy42b]

I have this bad problem of going too sharp or too flat on my brass instrument (horn) how do you overcome it? 

Details would help because this varies somewhat from instrument to instrument.  On trombone I stay in tune by making tiny movements of the slide.  On valve instruments I don't have that available, so I may be using alternate fingerings or embouchure adjustments.

Bottom line, playing in tune is a skill that must be practiced like any other.  IMO the absolute best way to practice this is to play alone with a drone CD. 

Hope this helps.