I reckon the guy han an Intellitouch tuner wich clips on to the top of the guitar. Mr. Happy may have misunderstood when the guy said it makes the guitar play "louder". It would certainly help to make the guitar play "better" as it enables speedy and accurate tuning of the guitar. It picks up the string sounds through "resonation" in the guitar "head" and is not effected by other sounds in the vicinity.