Determining Note lengths?

[Arnak]

Hi,

Can anyone advise me how to determine note lengths in Sonic Visualiser?

I have the St Mary's plugin but when the notes are detected they bear no obvious relationship to the sound file.

So much so that when the file is played back with the notes found it sounds nothing like the original...

The sound instrument is a simle bass guitar with no other accompliment.

Thanks,

Arnak