I'm sorry. Triangle might give you a decent sound, but saw waves are what you need. My first try at a trumpet-like sound, actually ended up sounding like a saxophone. I just bought my Gaia a couple weeks ago and still waiting on some cables to properly hook it up. I have it kind of jury rigged right now so that I can at least hear what I'm doing
3 saw waves: 2 of them are exact copies of each other to fatten the actual note so that the harmonics of the third which is set one octave higher and at half volume aren't over powering.
Initialize a new patch and set all 3 oscillators to saw
make one of the saws pitch one octave above the other two
select all three oscillators and set the filter to high pass, 12db per octave
The cutoff is 71 (just above half) leave the resonance at 0
Filter envelope: A:0 D:0 S:127 (100%) R:0
Amp level is 127 (100%)
Amp envelope: A:0 D:122 (96%) S:122 (96%) R:37 (29%)
This sounds remarkably like the trumpet voice on a Yamaha PSS-595, which used samples.
I got all the numbers from the Gaia tool by Grauw. Great tool, but make sure to download the Java runtime environment in order to run it. I'm using it to document all the patches I create.