vasilis wrote:When tapping a string on a fret, actually I hear the main harmonic of the note corresponding to that fret and also I hear a 2nd note corresponding to the length of the string behind the fret...snip...Is there any way to get rid of that 2nd note ? Could that have to do with the setup of the frets of the guitar?
I don't think so...it's just physics. When you hammer a fretted note from an open string there are two string lengths: distance from the saddle to the fret above your finger and the distance from the nut to the fret behind your finger. The note from the fret to the saddle is louder 'cause the sound comes off of the top (no top to resonate for the note behind to the nut).
The way to minimize the second note is to hammer as close to the front fret as possible...the further back you tap in the space between the two frets, the louder the second note will be... It also helps to work on keeping your taps even -- try not to vary the pressure but be consistent, and work on using the minimum of attack for the tap...just enought to get the note you want and not the note you don't want. Another approach is to tap up from a previously fretted note whenever possible or try moving the tap to another string.
Hope this helps...