This high performance echo unit features built-in reverb in addition to the basic capabilities of the SE-500. A single "auto-pat" input impedance control knob conveniently handles all signal levels form mic to line. With the balance control system anyone can easily mix echo and reverb, and direct and processed signals, for optimum sound quality and minimum noise. The reverb input balance control lets you adjust the relative amount of reverb applied to the direct and echo signals. That means you can add reverb to just one of those signals, or both. This advanced control capability offers many acoustic effects not obtainable with conventional echo machines.