In addition to shape, size, and material, how an exhaust tip is mounted can also have an effect on the sound your pipes produce. Tips that are welded on or mounted with compression clamps provide a more solid sound than ones that are screwed on. The reason is simple. They are less likely to come loose and add a rattle to your hum. Over time vibration will eventually loosen screw-on type tips, which are mounted on to the pipe with three bolts or screws, just like those ceiling light globes you have to remove when you need to replace a light bulb.