If anyone was interested, I was just checking the speaker volume (and bass) of the CK88 vs the P-125.
If you have a P-125, first put the piano on variation 1 (Live Grand).
Then put the volume on around 7.5 (using the 11 dots, and counting the first dot on the left as 1).
That will be the closest to volume and bass, although the CK88 will still have a little less bass ..... and more crispy highs.
The sound of the CK88 speakers are decent enough for quick solo practice in a completely quiet environment. Kinda low volume/bass. Bluetooth audio sounds okay coming through it. PC audio sounds decent enough. You can get a quick jam in, but yeah, nothing like the P-125 speakers.
I'm still concerned about the button lights, and may return it. I like to play at night, in low lighting, and knowing that I have to crank up my room lighting like a cafeteria,..... or use my portable music stand light every time is not something I enjoy. I keep thinking that maybe I'll memorize where everything is and not need to look very much? I assume we won't hear from Yamaha about possible lighting changes before my return window, so ...oh well....
And another thing I forgot to mention earlier on lighting is that you can't see what current category you are in, with heavy or low room lighting. Not a huge thing, but when you look down to see what category you're in, you ain't gonna see it.
I think it's ironic that one of the purposes/advantages of this really cool UI is for quick sound creation/improv/etc.. on the fly, on stage and such, but the button lights will probably make that very difficult for those that aren't playing where lighting is hitting that interface. Seems like, at the moment, you need to setup your live sets ahead of time, and just have the effects/layers ready to turn off/on (which you could do with about any board).