Hey Dill,
Maybe this pic will help...
The red baffle is the baffle that came with the pipes. It is spot welded in. The yellow baffle is one that I added. However that leaves that 2 1/2" empty area between the two that creates an "echo chamber". Because the sound bounces around and resonates badly, it can produce some pretty sharp sounds between 4000 and 4500 rpm. Below 4000 rpm it (especially at idle) they sound great. Above 4500 rpm (especially above) 5000 rpm, the sound is much more tolerable, but there is not much of a grumble (almost a sport bike whine sound). I am sure that it all has to do with frequencies (generated by the various rpms) and available echo area, but I am not an audio engineer, so I can't really explain it. I bet there are some mathmatical formulas, that may also include that I am runnning the bike a little bit lean as well.
One other solution I am thinking of, and I have no idea if it would work, is to eliminate the chamber completely. I would remove the welded in baffle and insert a 1 3/4" piece of exhaust pipe (I could get that at any exhaust shop like Midas) then use that inner pipe for baffles.
Soren
