[quote name='ikay' timestamp='1350114817' post='1834651']
I'd be interested to know more about the piezo nut concept, what sort of dimension does it add to the sound compared with the piezo bridge? I couldn't really identify it in the sample track
[/quote]
It will pick up the note behind the fretted note - so for example, when you slide up the piezo will pick up the other side of the strings so the note appears to fall or lower in tone as the magnetic pickup or piezo captures the rising note. ( you can hear this at 1.23 on the Soundcloud track during the solo)
It also picks up the open strings too so you can get unexpected jumps in volume as the other piezo or magnetic pickup is also picking up that of course, It's just a matter of getting used to. It suits an experimental approach but if your taste is more traditional you can mix it in slightly and this kind of replicates an acoustic effect (a double bass is subject to this phenomenon to a lesser extent anyway)