"skip" when digital reception degrades (similar to digital television drop-outs). Alternatively the HD signal can revert to a more robust 20 kbit/s stream, although the sound quality is then reduced to conventional AM-level. Datacasting is also possible, with metadata providing song titles or artist information. iBiquity Digital claims that the system approaches CD quality audio and offers reduction of both interference and static;. However, the data rates in HD Radio are substantially lower than from a CD, and the digital signals sometimes interfere with adjacent analog AM band stations. (see § AM, below). AM The AM hybrid mode ("MA1") uses 30 kHz of bandwidth (±15 kHz), and overlaps adjacent channels on both sides of the station's assigned channel. Some nighttime listeners have expressed concern this design harms reception of adjacent channels with one formal complaint filed regarding the matter: WYSL-AM owner Bob Savage against WBZ‑AM in Boston. The capacity of a 30 kHz channel on the AM band is limited. By using spectral band replication the HDC+SBR codec is able to simulate the recreation of sounds up to 15,000 Hz, thus achieving moderate quality on the bandwidth-tight AM band. The HD Radio AM hybrid mode offers two options which can carry approximately 40~60 kbit/s of data, with most AM digital stations defaulting to the more-robust 40 kbit/s mode, which features redundancy (same data is broadcast twice). The digital radio signal received on a conventional AM receiver tuned to an adjacent channel sounds like white noise – the sound of a , or a large waterfall, or a strong, steady wind through a dense forest canopy, or similar. All-digital AM All-digital AM ("MA3") allows for two modes: "Enhanced" and "core-only". In enhanced mode, the primary, secondary and tertiary carriers are transmitted, allowing for a maximum throughput of 40.2 kbit/s while using 20 kHz of bandwidth out to the station's 0.5 mV/m contour. Inside this contour, stereo audio along with graphics (station logo and "artist experience" album artwork) and text information (the station's call sign, title, album, and artist) can be decoded by the receiver. Beyond the station's 0.5 mV/m contour, typically only the primary carriers can be received, which restricts the maximum throughput to 20.2 kbit/s while only requiring 10 kHz of bandwidth. In core-only mode, the station only transmits the primary carriers. When the receiver can only decode the primary carriers in either mode, the audio will be mono and