This post could just as easily go on the Chicago board, but since it pertains to HD Radio I'm posting here. WFMT Chicago (classical music) appears to have finally tamed if not completely eliminated the high frequency distortion problem I have written about on previous occasions. I speculate that this distortion is caused by intermodulation between high frequency sidebands (probably the L-R channel) and the HD sidebands. It is particularly annoying on certain female (and also male) voices, but is less noticeable on musical selections unless they contain a lot of high frequency energy (like bells, for example).
The problem hasn't gone away completely but it's greatly reduced. I still hear traces on some announcers; mainly Lisa Flynn and George Preston, but it's not nearly as bad as it was. I don't know what they may have done to fix it other than perhaps reducing the peak deviation slightly-- or perhaps adding some sub-band filtering. Either way, I appreciate it!
The problem hasn't gone away completely but it's greatly reduced. I still hear traces on some announcers; mainly Lisa Flynn and George Preston, but it's not nearly as bad as it was. I don't know what they may have done to fix it other than perhaps reducing the peak deviation slightly-- or perhaps adding some sub-band filtering. Either way, I appreciate it!