I think EVERYONE here has the right idea ....
Feedback... have you asked someone to listen to you playing from a distance when you are playing the other horns
The 72 .... dark or not if a lead player can crank over a jazz band using the 72.. well you should be able to as well...
Equipment Issue ...have you checked your horn for
Is it clean ? a dirty horn would play like you state
Are the Valves aligned? same thing... if your felts are worn or got wet and threw off you alignment you aren't going to get any zing
Are your corks in good shape ...
Did you dent or mess your leadpipe or receiver?
Is your mouthpiece in good shape and does it line up with your receiver okay? Sometimes receiver get damaged to. Some mouthpieces match up better with certain horns too ... not likely but a possibility.
You might take it in to a tech for an evaluation.
if you have an instructor ... I would ask to use one lesson to go over this and see what he tells you ... be prepared to hear the horn is fine.... you just need to practice.
keep us posted