Did you mean that based your experience Android port on N900 provides louder and higher quality audio? On 3.5mm headphone output?

The loudness in Europe and some other markets is limited by EN50332 standard. The output with a pseudo program noise test should be < 150 mVrms. Androids should follow that too.

The (mp3?) decoders on Android and Maemo are likely different and have different quality. Try also other formats such as flac and ogg.