Unfortunately the distortion seems to be a fairly common IP2000 complaint in various forums across the internet. I found another long thread where users reported distortion starting after about 10 minutes of use playing piano. This makes me think the problem could be heat related...could even be related to the drivers overheating when pushed above a certain power level for an extended time.
If the distortion is happening in the IP2000's internal signal path, the only thing you can really do is try keep the signal level relatively low till late in the signal path. I assume you have already tried maxing out the Volume and Sub levels and sending a relatively low signal from the mixer?
If the distortion is happening in the IP2000's internal signal path, the only thing you can really do is try keep the signal level relatively low till late in the signal path. I assume you have already tried maxing out the Volume and Sub levels and sending a relatively low signal from the mixer?



Have you tried the Ip300?