Digital radio is essentially streaming audio over the air. Anyone who’s handled an audio file knows the rule of thumb: the better the bitrate, the better the sound. In the file-sharing community most songs are offered is 128kbps – okay, not CD quality, but not cruddy like a tape dub. Some audio encoders offer better quality than others, due to subtle differences in the encoding algorithm each system uses.
For “HD Radio,” the U.S. brand name for digital radio, the bitrate for most stations is expected to be between 64-96kbps, with AM running as low as 36kbps. iBiquity, the company behind the system, promises “enhanced sound fidelity” at these bitrates. In May the National Radio Systems Committee disagreed, suspending the official standard-setting process for the IBOC technology (at the heart of “HD Radio”) after declaring its audio quality unsuitable for broadcast, jeopardizing the full-scale rollout of consumer receivers for that all-important holiday season in the process.