I would prefer to restate the question as "How Well Does An Acoustic Petrof Upright compare with Pianoteq U4?"  Of course, this sounds ridiculous at first thought.  Upon further reflection, however, one becomes aware that even mass produced acoustic pianos have a ton of variability between examples of the same brand, model, length, and even manufacture date.  Such is not the case with Pianoteq, unless someone goes in and lightly randomizes some aspects as Unison Width, Damper Release Time, etc.

You are quite correct, and that's the reason I really don'e enjoy acoustics much any more.  I find playing the Pianoteq in my home, to be a much more satisfying experience than struggling with a heavy action Baldwin grand with overly hard hammers, and neglected tuning that belongs to a friend of mine.  It's impossible to play it with any subtlety.

Also, if you notice the digital representations of waveforms, one can see that the attack volumes were fairly normalized between acoustic and virtual pianos, but the Petrof's sound decayed sooner than Pianoteq's.  Of course, this could be made closer to one another by adjusting some of Pianoteq's soundboard characteristics.

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Personally, I would prefer to restate the question as "How Well Does An Acoustic Petrof Upright compare with Pianoteq U4?"  Of course, this sounds ridiculous at first thought.  Upon further reflection, however, one becomes aware that even mass produced acoustic pianos have a ton of variability between examples of the same brand, model, length, and even manufacture date.  Such is not the case with Pianoteq, unless someone goes in and lightly randomizes some aspects as Unison Width, Damper Release Time, etc.

Cheers,

Joe

https://soundcloud.com/portablehole/petrof-vs-u4