Avoid over processing the digital audio. Most stations have gone to great lengths to broadcast the cleanest digital audio that is possible. The digital audio stream compression and limiting should be set similar to the analog so that there isn't any distracting difference in the sounds. This can be a challenge while you try to keep the integrity of the HD Radio sound. The digital sound should remain open with as much dynamic range as possible. There will definitely be an improvement in stereo separation and the noise floor will be inaudible. There are other basic do’s and don’ts for HD Radio processing. When using an FM analog processor for the HD Radio audio path,remember to turn off the pre-emphasis. Do not use one FM analog processor and split the FM and digital audio streams at the output. This will also cause pre-emphasized audio to appear on the HD Radio signal. Try to use a separate processor for the digital transmission rather than spitting the FM analog output. Even an old processor sounds better than pre-emphasis on HD Radio.