Along with the EQ settings provided by Qberticus to hear the artifact more pronounced, I found that it is also more audible with all action noises turned off. This also led me to the conclusion that the artifact is not within these noises which narrows it down a bit.

Perhaps this won't be much of a problem once PT4 comes out.

However, I finally had some free time to identify what are the frequencies that bother me.

I start with the C3 Solo Recording preset and set the temperament to well tempered.

I'm going to assume the note C3 equals middle C.

If I play C1 without any equalizer changes I can hear it clearly but in case you cannot here is an eq setting that will exemplify the frequencies that cause the ringing for me. It is most notable in the mf-fff range but I can hear it even at p.

Equalizer = [3514, 3515, 3860, 3861, 4420, 4421, 4461, 4462, 4623, 4624, 4697, 4698; -25, 0, 0, -25, -25, 0, 0, -25, -25, 0, 0, -25]

This will really bring out the offending noise. They are very high order harmonic frequencies.

If I use this eq setting then the ringing noise is pretty much gone.

Equalizer = [3514, 3515, 3860, 3861, 4420, 4421, 4461, 4462, 4623, 4624, 4697, 4698; 0, -25, -25, 0, 0, -25, -25, 0, 0, -25, -25, 0]

However, it's only for that one note. You still get these obnoxious very high overtones in the rest of the bass. Setting the cutoff and Q factor doesn't help since it kills the high notes and makes them too flat (in the timbre sense).

I only have the standard edition but I don't know if even in the pro edition you can control overtones that high.

What is most interesting is if you set the temperament back to equal the ringing is not as offensive (i.e., loud / noticeable). So this leads me to believe that the model has some harmonic resonance at whatever freq C1 is when set to well tempered. Or something.

I wish I knew what causes this and how to control it since this problem limits how much I can play the C3.

Greg.

For me I can hear it in the  A2-D3 range but it's primarily on C3 that I can hear it. It's there for about 750ms after the key is struck in the f-fff range. I think it's in the 2500-3000Hz range thought I can't be very sure about that.

I use Sennheiser HD 555 headphones as my primary output but I've noticed this on other speakers as well.

By soundcard effect I thought maybe a mismatch between the pianoteq parameters and the sound card ones that can sometimes be modified independently might also have an effect on the offline rendering that uses these parameters since the renderer might also talk to the sound card driver.

@samplerate problem:
This is what I thought, too, but It doesn't change when you change the sample rate, except when you choose such a small sample rate that the noise cannot be covered anymore(sampling theorem). And like I said it is independent from the computer or soundcard. I tested it on several setups. The only difference is that depending on the frequency curve of your speakers it will sound very loud or it is hardly audible.
With extreme eq settings I can make it audible on any speaker system I have, but with "normal" pianoteq presets I hear it gently through my sony headphones(very bright sound, but other pianos sound really great on it) and so I didn't realize it before I got them.
Hope that makes it clear.

When I listen to your demo, I can clearly hear the metallic artifact with my headphones, so this is not an headphone problem. When I play myself with your fxp and reset the Eq back to 0, I don't hear any artifact, the stock C3 worn out also sounds ok. So your problem has to be a sampling rate problem or bad response from your soundcard.

Here is a spectrum of a note from your file at the top, and the same one played by me at the bottom. The peaks circled in red centered around 7kHz is what we hear as an artifact, and none appear in my graph. This is a clear sign of aliasing. Not a C3 problem.

just made a recording where I used extreme EQ settings to highlight the sound I am speaking of:
http://sebi.g3th.net/music/rattle%20c3%20demo.mp3

The first run is with the highlighted sound the second run is with the suppressed sound. I hope it will make clear what I hear.

@Rytmenpinne: I can try this on different headphones the sound is no distortion of my headphones since it doesn't depend on volume setting and if I add more gain to it i can hear it on other headphones/speakers too.

This sounds like numerical aliasing, not distortion. There is a strong component around 8kHz in the first part of your file that is causing this. What internal and external sampling pianoteq rate are you using and what is your soundcard spec in this area?

C3 sounds fine in my setup with Grado SR80 headphones and Tascam US-122 soundcard.

The first run is with the highlighted sound the second run is with the suppressed sound. I hope it will make clear what I hear.

@Rytmenpinne: I can try this on different headphones the sound is no distortion of my headphones since it doesn't depend on volume setting and if I add more gain to it i can hear it on other headphones/speakers too.