Easy.

Don't use the line in or mic in on your computer or laptop.

Instead, get pro audio hardware with ASIO and input your mic there (with a XLR or 1/4 inch cable).

A nice cheap one is a Presonus Audiobox USB (2 channel and can be used with the ipad)
Or the Zoom r16 (8 channel inputs and 32 tracks)
Or the Focusright Saphire (8 channels in and can be used with the ipad)

You are getting hiss either because (a) you are using consumer grade crappy audio ins on your computer, (b) you are using consumer grade crappy audio ins on your computer AND your cable may or may not be introducing MORE hiss or (c) you are using consumer grade crappy audio ins on your computer AND your cable may or may not be introducing MORE hiss AND your digital piano output may have a short or also be introducing MORE hiss.

Change your cable and try to record into a mp3 player or preferrably some higher end audio device, like a zoom H2 or H4 or any field recorder that is 'pro grade'. If you hear hiss and you changed out the cable, then it's the digi piano.

NEVER EVER record into your computer or laptop using what came with it, unless you just don't care about the audio quality or fidelity at all.

Mike

Last edited by karmacomposer; 01/02/13 03:02 PM.