I have searched everywhere I can imagine and I haven't found a sample of an Upright Bass (Double Bass/ Contra Bass) slap.
It sounds totally different from a normal slap bass - it sounds more like a "click".
My bandwidth prevents me from downloading Gbs of samplepacks. Does anyone know where I can get such a sample?
I'm pretty sure Spectrasonics Trilian (https://www.spectrasonics.net/products/trilian.php) has one. Not sure if that's what you're looking for though.
You're right. I think for that price, I could get a real-life band to play the piece.
I should have mentioned that I am looking for a free sample :)
You could try the BBC Philharmonia free orchestral samples pack* at https://archive.org/download/orchestral_samples - the "STRINGS" archive has some contrabass samples - the "arcocollegnobattuto" folder could be what you are looking for, if I'm not mistaken.
* This sample pack is advertised on our "Top Picks" page which can be reached through the "Web Resources" entry in OpenMPT's Help menu - go check it out for more interesting sample sources!
Thanks. That is what I was looking for.