Wirelessly posted
There was a tutorial where you use iFile to access a system sound file and you edit the values inside the property list viewer. You changed all the values to 25 I think. That number gave the volume output roughly a 25% increase. I used it on my old 3GS all last year and it was absolutely louder than stock. But when I tried it on the same 3GS after i updated to 5.0.1 I didn't notice any difference.
If you would like a link to that tutorial let me know and I'll find it. But maybe some other forum members can chime in if they think it's worth trying.