Thanks, Christoph
Yes, I continually have to remind myself regarding the difference between MIDI and analog.....or audio, digital, whatever "real" instruments are called.
I know that if I would "mic" my keyboard.....using two mics for its two speakers, left and right coming out of the top of the console......that would be a "real" instrument. (However, then it would also come in as "stereo"...with the lower octaves on the left channel, higher keyboard octaves on the right. Not particularly an acceptable idea.
What confused me is that if I would choose the "headphones/output" jack to bring it into the iMac audio line-in, it would also be a "real" instrument...or analog, etc. That's because, since my Yamaha keyboard is also a MIDI, I guess I just presumed that (excepting "mic" it) it was still MIDI. By the way, HangTime previously advised me that if I chose the "headphone/output" option on the keyboard, I would have to use extreme care with the volume...starting very low on the keyboard and then building up to where I would need to be. Otherwise, apparently, significant damage would be likely somewhere. Either computer,keyboard or both.
I don't think I will go with the GB MIDI output option. Too involved for me. But I truly want the keyboard sounds I play to sound like that in GB. I know that MIDI in to GB is basically a mathematical process, not audio. My problem has been, once the keyboard part is in, I simply cannot make it sound like the keyboard settings via GB. Not only that, the texture quality, velocity of hitting keys, etc. cannot be rectified in GB. At least by me.
Still not sure what I'll do about all this. Regardless of what I do, seems like I'll have to sacrifice something. For now, it would appear that I will do best to get the "genuine" sound of the keyboard into GB for playing things like "classical" music, and go MIDI when I want to play jazz, popular, etc. At least for the latter option, there would be other things going on.....like drums, guitar, horns......that alone should minimize the less than desired quality of the MIDI keyboard.
If you have any more for me, I'm here. In the meantime, thank you very much.