New BeOS users sometimes discover that audio is quieter in BeOS than it is in Windows or other operating systems. The reason for this is that Windows drivers add about +20dB of artificial volume to the output, while the BeOS driver is volume-neutral. This is very important to audio professionals, who will enjoy higher quality audio from BeOS than they do from Windows (Windows will distort output on high-quality hardware). Do not file a bug report — Be does not intend to „fix“ this situation. Just turn up your volume controls a little more.
However, there is a known bug with the Sound Blaster PCI 128 (and possibly other cards), which have especially low sound output. For instance you can have the volume at a normal level and you will hear nothing. This is a known BeOS bug which should be fixed in a post R.4.5.2 release.