Tri-X should not have what most people would call "obnoxious grain" unless it has been poorly exposed and/or beaten up during processing (or blown up a lot, obviously). Overexposure is the number one culprit in making a horribly grainy image in my experience. In fact, when I want to increase the appearance of grain, overexposing is the first and most important step. Another thing that causes a lot of grain to show up is when you "print up" an underexposed negative by reducing density on the print and adding contrast. Number three culprit: processing. Overdevelopment, too much agitation, agitation that is too harsh, etc. Number four: pictures that are not really sharp to begin with. This gives you nothing *but* grain to focus on. The worst *accidental* grain I have ever seen is from extremely overexposed, low contrast, out of focus negatives that never should have been printed in the first place being not only printed, but done so much too large.
When you print your contact sheets so that the sprocket holes are just barely visible using a number 2 filter (or a grade two paper), what do your pix look like? Light, good, or dark? Contrasty, good, or flat?
By what factor are you enlarging your 1x1.5 inch negs?
Changing film/developer is not anywhere near the first thing that comes to mind as a suggestion. You may like another film better, but developers will matter very little, and you should be able to get Tri-X to look perfectly fine with what you are using. Also, by doing this, you will learn better quality exposure and development that you can use to get great results with any film.