Octave Numbers

[Wodd]

I am curious about something. I read about instruments being tuned to a note followed by a number. For example, G-2 for a bass guitar or double bass. How is the 2 derived exactly? Is it based on the piano, with the leftmost key being, for example, C-0 or C-1? I understand that it is an octave number. But, what I am not sure of is how it is derived (as I am guessing that it is not "random").

[Saga Musix]

What you are looking for is scientific pitch notation. OpenMPT's octave numbering doesn't follow scientific pitch notation.

[Wodd]

That was what I was looking for. Thank you
I was not familiar with the term scientific pitch notation.