I had the same problem with ringtones and message alerts. Particularly those that I had downloaded from Zedge. They all seemed a little too quiet on the SGSII and Nexus One.
My solution was to...
1) Copy the tones to my PC desktop.
2) Download and install the very useful, and free,
Format Factory to my PC. See here:-
Format Factory - Free media file format converter
3) On
Format Factory I selected Audio and MP3 (it can handle a whole range of audio/video formats) and added a ringtone file from the desktop.
4) I then select Output settings and can then choose High Quality and increase the volume of the ringtone to 150% or 200%.
5) Once the conversion has taken place I can then place it back on my SGSII and the low volume problem is solved.
I also use
Format Factory for simple editing of video's.
Format Factory is a multifunctional media converter.
Provides functions below:
All to
MP4/3GP/MPG/AVI/WMV/FLV/SWF.
All to
MP3/WMA/AMR/OGG/AAC/WAV.
All to
JPG/BMP/PNG/TIF/ICO/GIF/TGA.
Rip
DVD to video file , Rip Music CD to audio file.
MP4 files support iPod/iPhone/PSP/BlackBerry format.
Supports
RMVB,
Watermark,
AV Mux.
Format Factory's Feature:
1 support converting all popular video,audio,picture formats to others.
2 Repair damaged video and audio file.
3 Reducing Multimedia file size.
4 Support iphone,ipod multimedia file formats.
5 Picture converting supports Zoom,Rotate/Flip,tags.
6 DVD Ripper.
7 Supports
56 languages
OS requirements: All Windows OS
Hope this helps.