Two-Handed Tapping
Tapping on a guitar (or bass) means tapping the fingers against the strings on the fretboard to make sounds. No striking, picking, plucking, or strumming is employed. Usually this means two-handed tapping, meaning to use the technique with both hands.
Two handed tapping is sometimes called ‘touchstyle,’ or ‘touch style,’ because the action of sounding the note feels more like touching than thumping the string. This is done on an amplified instrument to make the notes audible. Because it can be done with both hands, both hands can be used at the same time, like a piano player in a way.
It can be used to play polyphonic and counterpoint music on a guitar or one of the several specialty instruments designed especially for this technique. It can be used to play left-hand chords and right hand melodies much like ‘cocktail piano.’
It can be used to play basslines with simultaneous rhythmic chords. It can be used to play baroque music, and two-part songs as given in piano scores, and as exemplified in Bach’s Two-Part Inventions. And that’s not all …
How to Reduce or Eliminate Hum
Generally speaking, there is nothing in a guitar that actually generates hum, generally you can assume that the hum is being induced into the guitar, or it is being added to the signal of the guitar.
Experimentation is your friend. Here are some possibilities –
RECEIVING BROADCAST HUM
There is something in the environment which is “broadcasting” RFI in the room where your equipment is located. Common sources of Radio Frequency Interference include motors (vacuum cleaners, refrigerators, and automobile distributors), and transformers (high-intensity lamps, fluorescent lights), and from big magnets like speaker coils or television sets. The sound from autos are likely to vary in frequency. The sound from lamps and lights and refrigerators are likely to be be consistent, and at 60 cycles per second, which is what we normally call ‘hum.’
The RFI can be picked up either by strings (antennas) or by pickups (coils) as the signal is induced into the circuit created by the guitar and its parts, or into the cord (usually not possible if cord is properly shielded on both the guitar and the amp end), or into the amp, and then …