KCOH has, technically, sounded atrocious for years. It does sound like the audio is being fed over a dial-up phone line. They do have an STL dish at the studio...and my assumption is that the audio is being sent via STL...versus a phone line, or whatever. I, too, have been hoping that when the switch occurs, the "thin" sounding audio will go away and a fuller, richer audio will be the new norm. Hopefully the "culprit" is at the 1430 transmitter site and not at the studios on Almeda. I guess we'll find-out in a few days, though. It'd be great to hear some of those great bass lines in some of those great R&B songs of decades past (the Staple Singers "If You're Ready {Come Go With Me}, and "I'll Take You There" come to mind first). KCOH SHOULD be able to reproduce those bass notes with no problem (one of the great characteristics of AM). But, yes, it sounds like there are low-pass filters and high-pass filters set so that anything lower than about 2,000 cycles is rolled-off and anything above about 3,000 cycles is rolled-off.
I'd like to see the transition go smoothly and I'd be more-than-willing to volunteer my time and get with A.D. Rigmaiden and Mike Todd to see if I could be of any assistance before, during, and after that transition. I'll leave (phone) messages for both those gentlemen tomorrow.