Which sort of resonator tips? The big "coffee can" Bosal/Brospeed style weren't really resonators, as much as they were thick chrome tips that were just heavy and affected the sound of the exhaust along with the straight-through mufflers they were usually used with. The real Anza/Monza/Pacesetter resonator tips, with the muffler-style louvres built-in do affect the sound, but usually they just toned it down slightly, and more often than not they just gave a raspy note when used without any muffler in the system.
Real exhaust resonators, which are just small straight-through mufflers, just help to quiet down the exhaust note more than just a muffler itself will. Usually they are used to take care of any drone that might be present, or just prevent it, even if the system with only a muffler doesn't drone at all.
If you want a louder exhaust, use just a muffler, and no resonator.
Alternatively, you can use just a resonator, like a cherry bomb muffler or similar.