Anyone who has ever shopped for an iPod speaker knows that there is no shortage of models from which to choose' options range from giant party speakers in the form of old-school ghetto blasters to tiny units about the size--and shape--of a goose egg. Indeed, you can even find portable device cases with speakers built right in.

Portable Sound Laboratories started cranking out its original iMainGo speaker case back in 2007 and followed it up about a year and a half later with the impressive--and cheap--iMainGo 2. Since reviewing that unit, I've been eagerly awaiting the next offering from the company. It arrived not long ago in the form of the iMainGo X, which offers more features--and a noticeably higher price tag--than its sibling.

In fact, the X isn't a replacement for the iMainGo 2 but an addition to the line. While not entirely unwelcome, the iMainGo X is tougher to recommend at its current price of $69.95, since you get the same volume boost, audio quality, and case enclosure as the 2. However, there are a smattering of useful extras that some users might find compelling enough to warrant the $30 jump in price.

For one, the iMainGo X features dual-headphone jacks on the front, so in addition to letting you share tunes out loud on the go, it also acts as a splitter in a pinch. You can also daisy chain several units together using headphone port number two, as plugging into that jack alone will not silence the speakers. In addition, there's a mic input, which can presumably turn the unit into a portable karaoke system or, apparently, an amp for an electric guitar.

As for the rest, the X functions in the same way as the 2. A power button (which is a little too recessed for my tastes) turns the unit on and off, but you can continue to access the remainder of your music controls on whatever device you have attached. Most MP3 players and music phones will fit into the case compartment, which features a clear, plastic window for operating playback--and it does work for touch screens as well as tactile controls. There are a couple foam pieces to help with a snug fit, and an integrated 3.5mm plug serves to pipe tunes from the audio player to the speakers.

Sound quality is pretty decent for a unit this size' it's clear of any background hiss and not hollow-sounding at all. Bass isn't going to blow your socks off, and the highs aren't sparkly, but audio is solid enough for portable use. My only major complaint is that the speaker doesn't like to stand up on its own, so music often must be piped straight up. Also, it's kind of heavy overall, so even though it's compact, you'll probably notice the difference to your carry-on.

In addition to the iMainGoX unit, the package includes a removable strap and soft pouch for travel purposes. There's also an AC adapter for charging the internal battery, which is rated for 12 hours of playback.