128kbps MP3 is no longer a viable option for mainstream radio broadcasting. The format's limitations become glaringly apparent when compared to the more modern 64kbps AAC+: the former is outdated and can't deliver the same audio quality at lower bitrates.

One key issue with MP3 is its psychoacoustic model. It relies on complex math to identify and reduce audible aspects of music, which leads to compromised quality, especially on lower bitrates. In contrast, AAC+ uses more advanced tools like spectral weighting and transient masking to minimize audible degradation. This makes AAC+ a far more efficient codec for delivering good audio quality at lower bitrates.

Additionally, radio stations broadcasting in MP3 at 128kbps might experience noticeable artifacts like pre-echo, intermodulation distortion, and an overall grainy, digital sound. In contrast, a well-optimized AAC+ stream in 64kbps will typically exhibit much cleaner, more pleasant audio.