Dark and beautiful

That is some crazy business Mikko. Sounds really rich and full. Impressive!

Thank you both! Choosing a very rich and full reverb also helps, for the sake of honesty I'll do some dry demos also at some point 😃
Some upcoming tweaks include fixing a couple of sample start points, very mild noise reduction and cleaning up (I already removed some obvious leaked stuff with SpectraLayers but some more thorough spectral editing is upcoming) and fine tuning of the velocity switching points, I feel that the pianissimo and mezzopiano layers could extend a bit higher to allow easier soft playing.

Today I sat down on a nice Clavinova and tweaked the velocity switch points, making the instrument significantly nicer to play on a hammer action keyboard. I also included pedal noise samples, personally I hate those on virtual pianos but I know many people love them so now there is that option.

How hard is it to make one of these?

@Isaiah Landin depends a lot on the overall realism and playability you're looking for. Check out www.pianobook.co.uk where you'll find hundreds of examples of instruments sampled in various different ways. Some people just use a simple handheld recorder like Zoom H4, record every fifth key in just one velocity and end up with a decent sounding and lightweight library, although not really good enough for any serious solo piano stuff. On the other end there are people who have access to a professional studios.

I'd say Helsinki 1967 is somewhere in between, since my piano is located at a very quiet rehearsal space with professional acoustic treatment and I have access to some nice mics. Recording the samples took place last Wednesday between 10 am - 16 pm, and this includes setting up all the stands, mics and cables and having a very brief coffee/snack break at one point. Editing and rendering all the samples took another several hours, I advise to be VERY organized especially if you're working with several different mics and velocities. I used this naming syntax: C3_57_C3-C#3_0-30.wav, so basically ROOTNOTE_MIC_lowestkey-highestkey_lowvelocity-highvelocity.wav. In Kontakt this makes mapping the samples to the right zones super fast.
In DecentSampler, I basically prompted ChatGPT to write the xml-code for me since inputting lines for 300+ samples manually would have taken a very long time.
If you end up trying with DecentSampler, feel free to open Helsinki1967 file with your chosen code editor and see how it's done, you can copy it freely.

Three velocity layers per key is a good starting point, Kontakt Factory Library piano sounds and Logic's default piano samples sound very decent with three layers.
If your piano is in a not so great sounding room, stick to close miking the soundboard: on an upright, just two Shure SM57s can give great results!

What an awesome thing to do and even more to share!

Just hollering here to let everyone know that today I made some significant changes:
- Some phase re-alignment with Auto-Align 2, since after editing the samples and their starting points, the phase relationships were not as accurate anymore
- Fine tuned the panning of 57 samples (narrower) and OM1 samples
- Significantly reduced noise especially from 57 samples. I think I managed to do it with very little loss on the overall tone, thanks to SpectraLayers. Some mild de-noising on OM and room mics too.
- Now Kontakt users can also adjust the level of release samples!
- DecentSampler version is now much closer in overall quality to Kontakt, thanks to re-converting it with ConvertWithMoss which automatically gainmatched everything. Logic EXS version still needs some work, so the version available on Mega still has plenty of noise and those panning and phase issues.

Now after the phase tweaks, the instrument also sums to mono very nicely, which is a feature I very much appreciate on piano samples that I use on gigs: many super lush and wide grand piano libraries tend to lose most of their mojo on a typical PA system, because they were not designed for mono/almost mono playback.