The Alpine TUA-T550HD is an HD Radio tuner module, which, when connected to an Ai-Net compatible Alpine car audio receiver (nearly all of them are), allows the reception of digital radio broadcasts. The device is fairly straightforward: you connect it between your car's antenna and the receiver and the broadcasts come in.
However, when the TUA-T550HD is connected to one of three very specific Alpine receivers (iDA-X100, iVA-W550 or iDA-X100M) and a compatible Apple iPod, an additional function is activated: iTunes tagging.
Designed to be tucked out of view and controlled remotely by the Ai-Net compatible receiver, the TUA-T550HD is simply a metal box. At one end is the connection for the wire harness that supplies the TUA-T550HD with power and at the other are the input and output ports for Ai-Net connections, USB input and output ports, and an input for connecting the vehicle's existing AM/FM radio antenna.
The TUA-T550HD's simple design means that it can stand up to a fair amount of abuse from bumps and kicks, but you'll want to mount it out of the way, for example, under the seat or behind the dashboard.
Installation of the TUA-T550HD is as simple as finding a location for installation in the vehicle's cabin and bolting the unit to the vehicle's body. The included Ai-Net output cable is routed from the device to the receiver. Any other Ai-Net compatible devices--such as CD changers or satellite radio receivers--can be daisy chained through the TUA-T550HD's Ai-Net input. If using the TUA-T550HD with an iPod compatible receiver, the units are USB connected and the USB pigtail is routed to an accessible location, such as the glove compartment. Connect the vehicle's antenna to the TUA-T550HD using the included antenna extension cable. Finally, tap 12 volts power and ground locations and connect the wire harness.
When connected to a compatible iPod and one of the aforementioned iPod compatible Alpine receivers, the TUA-T550HD gains the ability to iTunes Tag song information. When playing back an HD Radio broadcast that includes artist and song title information in its text stream, simply hold down the select button on the receiver to save the metadata onto your iPod. Later, when you connect your iPod to your computer for syncing, a new playlist will appear in iTunes under the Store heading called "Tagged." In this playlist will be the songs tagged earlier with--if available in the iTunes Store--a 30-second clip. If you still like the song at this point, you'll be able to download the song from the iTunes Store.
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.