In the article the question is asked why, if my synth has line outputs, do I need a DI? The answer is that the DI provides isolation between your keyboard's grounding scheme and that of the sound/PA system. This is accomplished through the DI's transformer, without which the system would produce humm and buzz. Another reason is that the line out's on your keyboards produce a much higher signal than what a mic input can accept so the DI also breaks the line level voltage down to mic level voltages.

22-May-10 04:23 AM