well you could bounce it as an audio track to change it form midi to audio...and then eq the higher frequencies.

What The Bear said, and/or:

Use a different trumpet patch. BTW, what card/module/keyboard is the trumpet being generated from? Onboard MIDI sound, Soundfonts, etc.? Maybe it can be adjusted somehow?

Mix and match different patches/sounds. You may even find transposing the key up or down an octave (+/- 12) of another instrument, and mixing it in will give pleasing results. Just copy the trumpet track to a new track, assign it a different MIDI channel, and play around with another patch.

Perhaps you have several different trumpet patches? Maybe one starts out blatty and bright, like a real trumpet's first blast? One may sound more leveled out and a bit duller? Think about what a trumpet sounds like. That first initial rush of air is maybe a bit brighter and, then it settles into the note as a note is held longer. If you have two patches, shorten the initial attack notes or bring down the volume as the held note comes in. Mixed properly, it can sound pretty good. You may even want to try some slight modulation toward the end of longer held notes...like the player is running a bit out of breath.
Just make sure they are panned the same, and has about the same reverb, if it's a lone trumpeter.

Maybe it doesn't have its own space? How are things panned? Is this a lone trumpet, or several playing as an ensemble? If it's a lone trumpet, make sure it's down the middle, and all the other horns and stuff are panned out of its way. Maybe then it won't need to be turned up so much, because it's riding between everything else, not trying to sit on top? If it's several trumpets, maybe try actually panning them away from each other, so they don't all stack up on each other? Say you have two trumpets playing slightly different notes. Maybe try panning them at 10 and 2 o'clock. If you have several other horns, play with their panning positions. If they are playing mainly a wash of background, pan like elements away from each other, and maybe far left and right. Got two trombones? Pan them mostly opposite. Got an English horn and a French horn? Pan them opposite. String sections? Pan two different ones extreme left and right? If the brighter of the two strings is panned left, pan the brighter of two, maybe, brass sections right. Experiment with the panning of all the background instruments, especially the ones that sound similar...away from each other. Maybe this thing needs extreme pan, this needs 9 and 3 o'clock, etc. I try to pan the higher pitched background instruments more extreme, and as the instruments are pitched lower, more toward the center. That seems to make the bass in the middle spread out smoothly towards the instruments as they move out of the center. It's easier to tell the pan positions of higher pitched instruments, anyway. Almost like it lifts them out and up.

If you have three trumpets, pan 9, 12, and 3 o'clock, (or maybe 10, 12, and 2) adjusting the panning of anything else that was there, a bit inward or outward. If you have only one trumpet, put it down the middle that you have just carved out with all this panning. If you layer or mix'n'match this one trumpet track, pan it the same.

Maybe it's just a matter of getting it into its own space? You'd be amazed at how much stuff you can cram into a recording and still hear all of it with good panning, reverb, etc.

If you don't know about you Event List Editor and Piano Roll in your MIDI app, it's a good time to get familiar with those.

First, you'll want to leave a measure clear at the beginning of a tune. The first thing you may want to put on track one is a Sysex Message to autosend that tells your card/module to reset. It could be GM, GS, or XG...depending on your equipment. If you have two different modules, put a similar message on, perhaps, track two.

Then, you'll want to insert a patch change message for each track. This ensures that no matter what, before that tune starts playing, it plays the proper patch. I used to put EVERYTHING at the very start of a tune, in that first measure. That's definitely a good place for Sysex messages. I found that it made it harder to navigate to the messages for each track, if a track didn't start for awhile. I have since started putting my patch change and parameter entries immediately before the first note of whatever is in a track. This gives me a better quick visual in the tracks view to where a track starts, and I can zero in on it quicker. It also keeps the sequencer from sending 50 tracks worth of patch and controller info from some of my more ambitious tunes all at once at the beginning. Never crashed, but I did have a few stutters.

Then, you probably want to manually insert volume, pan, reverb, chorus, etc., messages for each track. (The drums generally only need it on one track since they are all responding to MIDI Channel 10. As a matter of habit, I stick it in the beginning of my kick drum track). This ensures that each time that tune starts, everything is panned properly, and you get no surprises in volume levels, etc. Sometimes, if you make changes later in the tune, and stop to back it up to start something again, it "remembers" the latest changes you made, and will start the tune with those changes...which is different than what you wanted at that point in the tune. So, entering that stuff in guarantees no surprises.

In the Piano Roll, you can bring up a track or two of the trumpet and play around with drawing in modulations, fade-in/out, etc. If your card/module responds to filtering, maybe you just need to manipulate the sound a bit there to mellow it out? A trumpet can be fairly bright at first blat. Then it can settle and get mellower. Some things can respond to messages telling it to basically change the tonality. Sometimes you can draw these in, or maybe even use a pitchwheel that's been reassigned to it.

Think about what a trumpet does. Listen to some stuff with trumpets, especially in the style you are attempting. Listen through headphones to see how they pan that kind of music.

Once you start getting into all this stuff, it'll be second nature to quickly enter all these things. Pan is controller 10, volume is 7, reverb is 91, chorus 93...etc. I know this stuff by heart, and can quickly enter thses things. No MIDI track I create starts without Sysex module resets and patch and parameter settings for each instrument.

And be careful of more than one instrument sharing a MIDI channel. Anything you do to one will affect the other. You can have different instruments on the same channel in one sequence, but they must be routed to different modules to keep from affecting each other.

Hope this helps more than it confuses. You'll save yourself a lot of headaches if you learn to do all this quickly and easily. And, it will be easier to tweak things in a hurry when you know what and where everything is.

Have fun, and good luck.

Kapt.Krunch

Wow, that's a lot of info...thanks so much!