Each song tag is only 512 bytes, so a nearly endless number of songs can be tagged when an iPod is connected to the system. If no iPod is connected, the TUA-T550HD can store up to 50 song tags on its internal memory. When the iPod is connected, the tags are transferred to the device and the memory is erased to make room for new tags.
Alpine states that iTunes tagging works with fifth-generation iPods, the iPod Classic, third- and fourth-generation iPod Nanos, and the second-generation iPod Touch. Through testing we were also able to tag songs on the first-generation iPod Touch. USB mass-storage devices and other MP3 players are not supported for tagging.
We installed our test TUA-T550HD unit into our test vehicle and connected the device to the Alpine iDA-X100 receiver. In the San Francisco Bay Area, there are about 26 HD Radio broadcasting stations, so we had no problem finding a station for testing. In the upper left corner of the iDA-X100's display is a small line of text that indicates the status of the reception: DX for analog and DX Digital for HD Radio. When tuning into a station, the analog broadcast is first received. After a second or two, the digital broadcast is detected and supersedes the analog portion. The effect is an immediate increase in depth and fidelity of the sound. We wouldn't be surprised if someone told us that Alpine left the lag there to illustrate the night and day difference between the analog and digital broadcasts.
Many of the HD Radio broadcasting stations feature multicasting, which is the broadcasting of substations within the same frequency. With our TUA-T550HD/iDA-X100 combo, we were able to switch between substations with a press of the select button to bring up a list of substations. For example, our local Top 40 station featured an indie music substation that offered a wider variety of music. Unfortunately, the TUA-T500HD can only read the text information from one station at a time, so knowing what was playing on the other multicast station required switching to the channel. It's a minor inconvenience at best, but since we're already tuned in and receiving the station, we'd like to know what's multicasting before switching.
Adding about $200 to the cost of your Ai-Net compatible receiver for HD Radio reception may seem like a steep price to many, particularly if you're of the sort who listens to your iPod more than the radio. However, for those who listen to broadcast on stations that offer HD Radio, we feel that the TUA-T550HD is a worthwhile addition to your listening experience. The increase in audio quality for music and talk radio and the additional programming gained through multicasting is worth the price of admission alone. The iPod/iTunes tagging is really just the icing on the cake.