Hi Eric,
Because they are Rhodes Performances, you might want to dig into the programming a bit as it is the goal of the programmers to make the sound distort and bark when you increase the play velocity. Not saying you don’t have a problem but the actual Rhodes (and FenderRhodes before them) could be a bit scratchy and distorted at times — and since accuracy is a goal of programming, let’s start with exploring the Effect processing used and see whether or not the sound quality is intended... or is a problem.

(Reinstalling firmware would do nothing — that is not how that works).

Second, if other sounds are not exhibiting the same quality, then it is even more likely that the quality is, indeed, intended. You can be specific on this forum, speak directly about specific Performances. Most effects are programmable, by that I mean if an edgy quality is programmed in, you can usually adjust how much of it you are getting. This can be achieved by an Assign Knob, or a Slider adjustment.

Often an Insert Effect that is some kind of an Amp Simulator is used to recreate that edgy sound.

The other possibility is the system you are currently listening to is being overdriven. It’s not really possible to give you a definitive answer without actually being there.
But lean on your own experience with the Rhodes — Part of its thing was the “edge”. If you don’t have experience with the real thing, ask around. Find old recordings...

On the HOME screen, tap the “FX” to take the shortcut to the Bypass screen... temporarily bypass the INSERT and SYSTEM effects, this will tell you instantly how much influence the different processing blocks are applying to the sound.

Thanks for you quick reply and help! I fix the distortion (it was sorta like a speaker breaking up from being played too loud.) What i did was i lower the output in the audio output to +6db It was set at +12db at the Audio I/O. IT showed ranges from -6db, 0db, +6db and +12db. There is no breaking up now! What should that level be set at? is 0db ok too?

Cannot say, sounds like an issue with your sound system. Set the overall output level to match the input sensitivity of the device you are plugging into... +12dB is an extreme boost. Why was it set there? That would most certainly overload most devices you would plug a MODX into...

What are you plugging your MODX into?

0dB is the MODX initialized default.

I've had to set my keyboard to +12dB for sound folks who claim my level is too low to get any more volume out of (for monitors/FOH). So I went +6dB and +12dB which finally stopped those complaints. But +12dB doesn't work for my HS8 setup in the studio. So I have it set back to 0dB. Honestly, I do not switch it back/forth depending if I'm at the gig - so the same sound crew is somehow now dealing with 0dB. What they don't know won't hurt them. No complaints since I pulled the rug out.

At the studio I've got the Main L&R outputs routed into an audio interface with a clip and a signal LED on each channel (two "bar" meter). I can easily see with the "meter" if distortion is coming from clipping or not. At least due to output-of-keyboard to the rest of the signal chain. I have previously had a direct-connect without any device between and "clipping" is easy enough to hear vs. distortion or bark that's intended.