| Derek,
Ear training is vital to good trumpet playing (yes, all of you college students out there, it's more than an NASM requirement). The ability to hear accurately will reflect in your ability to cultivate the center of the sound. As Dick Vitale would(n't) say, "it's all in the resonance, Baby!".
I used to notice during my years in Rotterdam that it was harder to play in tune after summer break. Solitary practice (not that I did much except at the driving range) is a poor substitute for playing with other instruments/intonation standard (usually the loudest choir and not the principal oboe, in spite of what he/she thinks!). It's also fun, if you have the opportunity, to sit at an organ and sound pedal notes with your feet while playing your horn on top. The organ can play forever (a hypothetical concept, perhaps) without taking a breath as well. Double the training and twice as much fun (I'm easy to please on occasion -- ask around).
Best,
EC |