Well, unlike WAMJ (107.5 frequency) which has the two subchannels you mentioned, Hot 107-9 simply had the main subchannel that was the digital format of their analog broadcast. Sound quality was great too, just like their WAMJ/WPZE counterparts!
As of lately, however, I noticed that 107.9 has only been broadcasting in analog format, and was just curious to know if perhaps there was some sort of equipment failure, or if a decision was reached by the suits to discontinue HD broadcast on this frequency.