The controls are, 'compress', 'bright', and 'volume'. The reason I decided to add a brightness controle is because compression often affects the perceived brightness or high-frequency content. By adding a brightness knob you can counteract the 'dulling' of compressed tone. The LS compressor also has an internal input sensitivity control. This means you will be able to use this stomp box in your studio to run keyboards, drums, or even master recordings and other line-level audio. This circuit is a studio grade compressor in a 2 3/8 X 4 3/8 X 1 1/4 inch stomp box.