Same Pianos - Different Sound

YouTube has additional audio processing, they normalize all audio to -14 LUFs, which means that some compression, normalization, and dither is applied to any upload.  It's further possible that in preparing the video, the author may have applied some minor sound editing/fx that technically wouldn't have "modified PTQ settings" while still changing the audio very slightly.  That said, I strongly suspect any difference will be due to YouTube sound processing (and perhaps even the volume of the youtube video).  Even the sample rate between PTQ, the VST host, and YouTube can vary which will color or change the sound.

I personally have a hard time with getting PTQ sound mastered for YouTube, as orchestral/symphonic pieces that have a lot of dynamic range get very little change from YouTube's normalization and sound processing, where -14 or -15 LUFs is easy to target and basically occurs "out of the box" while a piano solo (and even worse with a harpsichord solo) comes off as twice or thrice as loud as it should because YouTube's normalization/compression colors the audio too much.  Typically, I've had the best success by adding a voice into or outro to my PTQ demos for YouTube, because that adds enough dynamic range to the mix that the normalization doesn't go as wild as it can with a simple, quiet piano piece.  So, again, my guess is that YouTube is "interfering" with the demo, which prevents it from being exactly what PTQ rendered, and if you got a hold of the original source file for the video, they would likely sound identical.

Where did you get the MIDI file to play "the exact same piece"? The difference could be there! If you played it yourself and/or picked a MIDI file from a different source compared to the video. Velocity levels can be very different from one MIDI file and another "identical" one, and that can have huge effect on sound, even though it's not clear to me what "present" or "close" means to you, so it's not clear to me if they could have the effect you are hearing. If you upload your file (MIDI and/or wav/flac/mp3) we will understand better what you mean, and possibly hear if the MIDI file you used was dramatically different than the one they used in YT.

Chopin87 --

The notes for the youtube video states they are using 7.5 as am I...

It's not clear to me what you are comparing then. Perhaps you can be more specific about the youtube finds you are comparing with each other, and how are you running Pianoteq in your computer (if that's part of the comparison).

Thank you for taking the time to explain it. I am not familiar with Logic Pro, I only have pianoteq. I see it's a Mac DAW, but is Logic Pro something that converts MP3 to MIDI too? Otherwise I can't understand how that mp3 file can have anything to do with pianoteq, you would be just listening to an MP3 of a different piano.