You do not have remote gain adjustment capability on the stock Esky radio, just a HH on and off switch as you stated. The music you hear is caused by the ESC. The actual sounds are coming out of the motor oscillating at different frequencies. It depends on exactly which ESC you have as to what two beeps indicates. If you have the manual for the ESC ( and it makes sense in English) look at the manual to find out what two beeps indicate.. It may be the indicator that the brake setting is off. ( you don't want the brake on, by the way...)