Slacker sets you free to listen to customized radio

Have you taken note lately of all the ways to carry music in your pocket? The iPod lets you schlep boatloads of songs from your own collection. Zunes, Sansas and other gadgets let you listen to an unlimited number of "rented" tracks, provided you remain a paying customer. Portable satellite radios from Sirius and XM serve up numerous channels that cater to very specific musical tastes.

That wouldn't seem to leave much room for the new Slacker Portable I've been testing. But it adds an attractive if imperfect option.

The device finally started shipping the other day, not quite a year shy of when the free Slacker Personal Radio online service first launched.

Slacker on the Web lets you construct custom Internet radio stations you can listen to on a PC. You type a performer's name and then choose which related artists to add. You can fine-tune Slacker stations by having them play more familiar hits, or obscure ditties. In all, Slacker has more than 2 million songs (from major labels and independents) and over 10,000 artist stations.

The portable player lets you access those stations wherever you happen to be. A station's programming lineup of songs is refreshed whenever you tap into a Wi-Fi network or connect a USB cable.

But here's the delicious part. You need not be tethered to a computer or have access to Wi-Fi to listen, because songs are "cached," or stored in the device's memory. And that means you can use Slacker on the subway or an airplane.

Slacker fills a niche not directly addressed by rivals. For all the musical genre stations on XM or Sirius, for example — and I'm a big fan of both services — the satellite alternatives don't let you customize your own channels.

Slacker is free, unlike subscription music services such as Rhapsody.

The benefit against an iPod or other MP3 player is that your own collection of tunes might grow stale — and you don't always get around to loading new stuff.

And by connecting Slacker via USB cable to a PC, you can load your own tracks as with any standard digital player, provided they're in the MP3 or unprotected WMA formats. This option is not available for Macs.

Here's a closer look:

•Slacker basics. Slacker Portables come in three flavors: $200 for 15 stations and 2 gigabytes; $250 for 25 stations and 4 GB and $300 for 40 stations and 8 GB. If you wish, Slacker will preload your preferred stations onto the device when you order it.

You also can add, remove and alter stations after the fact. But you'll have to do so using software controls on the PC desktop or Web, and then use Wi-Fi or USB to update the device.

If you don't exhaust station limits, Slacker will use the extra room on a device to load more music on the stations you've chosen.

My custom Beatles station also featured tunes from Herman's Hermits, The Rolling Stones and The Yardbirds. The Beatles played intermittently. I built separate stations around Duke Ellington and Neil Young, among others.

All your stations are refreshed at the same time; you cannot cherry-pick to update some but not others. Syncing takes a second or two per song, depending on your Internet connection.

While you can refresh the devices at a Wi-Fi hot spot that requires a network key, you cannot connect to a pay network that requires a user name and password or that makes you click on a user licensing agreement. Slacker lacks a browser.

A future car dock accessory will let you refresh (but not stream) stations via satellite.

The 4.6-ounce devices are physically the same size — a gentle way to say the Slacker Portable is large and so-so looking. It's slightly heavier than an iPod Touch but more than twice as thick. It's a little bigger (but lighter) than a Zune.

Navigation is a bit crude. Volume controls are on top. On the right side is a scroll wheel, plus buttons for home, skip and pause. But an alternative "touch strip" navigation control on the left edge is so ultrasensitive as to be useless. (Fortunately, you can turn it off.)

You will welcome the extra real estate on the roomy 4-inch screen, which can display album cover art, artist profiles and, in some cases, reviews. But it can't display videos (or your own pictures).

•Sour notes. The sound was generally excellent using the supplied earphones; there are no built-in speakers. But more than once I encountered momentary hiccups near the beginning of some songs. And there were occasional buffering delays between songs.

You can intentionally pause a track in the middle or skip ahead. You cannot rewind. There are other restrictions, unless you spring for a premium subscription plan.

You can skip a song only up to six times an hour, per station. The name of the next artist to be played is displayed on the screen but not the actual title. Slacker's on-board "intelligent DJ" handles the skip limits.

Premium subscribers ($7.50 a month on an annual basis) can skip as often as they please. The premium service won't have audio ads (which are otherwise coming).

Subscribers can also hit a "favorite" button on the device as they listen to a song to store and play it at any time. You can hit a "ban" button to avoid particular songs.

Slacker says the removable rechargeable battery will last up to 10 hours of playback, which seems wimpy. Still, Slacker Portable is an intriguing device that promises to only get better in the future.