I don't know if there was more than one Centaur there or not - one of them was mine.
I didn't get around to set the volume on all my machines as my time was extremely squeezed (being one of the organizers, anything that goes wrong ends up being my problem). So, it probably wasn't turned up.
I plan to bring them already turned up so I don't have to worry about that at the show (I brought over 30 pins last year, so it takes time to get them all "happy").
If this happens again, ask at the front table and if it's mine, I can turn it up. You are correct - the sounds are awesome!
Mark