Tuning forks or anything else that just genorates tones to tune to is very impractical and a band gigging situation. I am also a blind musician and have been handing off my guitars to band members before shows to tune. I just stumbled on this discussion and wanted to chime in through my own personal experience. In a gigging environment, at least atmost places I play, between sets, or when we're showcasing, the house music is usually pumping and half the time it's pumping through the stage monitors. Maybe some of you are good enough to tune an electric guitar with the amp still on stand by to a tuning fork in a 100DB environment, but that's not me.

Also we need to consider speed. When my 7 piece original band is showcasing we have a 45 min set, with about 5 minutes set-up time. Tuning to tones will eat my whole 5 mins, never mind hooking up the rest of my rig. Tuning to indicators is far faster I'd imagine.

Playing in bands where we do 4 sets and play all night, it would also be nice to achieve the type of retuning between songs that doesn't draw attention to itself. Not much will clear a dancefloor faster than right after a killer dance tune, the guitarists starting tuning out loud with amps still blaring. Always smarter to run your tuner in front of your volume peddal, turn the volume down and be able to tune. With my current set-up, unfortunately this isn't an option, so one of the things that annoys me more than just about anything else, I'm forced to do.

I'm going to have to check out this tuner that has different sounds for sharp or flat and in tune. I've wanted something like that for a long time, but just haven't done the research to see what's out there.