The Sony RDP-XF100iP speaker dock may not have the catchiest name, but its sound is unmistakable. Compared with any other compact portable system we've tested in this price range ($249), this little Sony boom box packs a low-frequency punch that seems impossible for its size. Extras such as FM radio, remote control, integrated EQ, and a replaceable rechargeable battery pack only sweeten the deal.
The RDP-XF100iP has all the hallmarks of a Sony product. The design is clean, modern, and restrained, using a mix of high-gloss black plastic across the top, matte black plastic around the back, and a satin-finish metal speaker grille on the front. Total dimensions are 6.5 inches tall, 14 inches wide, and 4.75 inches deep.
A traditional scooped universal iPod/iPhone dock cantilevers out from the front, which can be flipped up and out of the way when it isn't needed. The dock includes two plastic inserts that conform to the iPhone or iPod Touch, but they really aren't necessary unless you're a stickler for a snug fit. Since the dock conforms to Apple's universal standards, it accepts any insert you may already have for your iPhone or iPod.
Above the dock, a glossy black strip of plastic runs across the bow, showcasing the Sony logo at the center and a small OLED screen on the left. The screen is used to display the speaker mode (iPod, Radio, Aux), as well as FM radio frequency and system menu information for EQ presets, radio presets, and a mono mode. The display isn't the brightest or biggest we've seen, and it doesn't include RDS station info or a clock, but it does the trick.
Across the top edge of the speaker you'll find an illuminated power button sitting alone on the left, as well as 11 additional buttons. Eight of those 11 buttons are grouped around the center, offering a mix of track control, radio tuning, system menu control, and radio preset skipping. Off to the right you have plus and minus buttons for volume control, and a single EQ button for jumping between presets. All of these buttons have a finger-friendly concave design and respond to just the slightest touch; however, the response time is surprisingly sluggish compared with using the remote control. We were also a little disappointed to see that only the power button is illuminated, making it difficult to discern the function of the 11 other buttons under dim lighting.
The back of the RDP-XF100iP is surprisingly bulky for a portable speaker system, compared with recent offerings from Altec Lansing and Logitech. If you're looking for loud, deep sound, though, it's easy to forgive the speaker's heft and thickness. A small recessed handle on the back helps with portability, and also acts as a ported woofer. Below the handle you'll find the expected sockets for a 3.5mm aux input and a power adapter. A sturdy, retractable metal radio antenna sits back here as well, extending upward with a slight backward slant.
You'll find an unexpected feature on the bottom of the RDP-XF100iP: a removable battery pack. It's a nice feature to have, if you ever wanted to stock up on extra packs for an extended time away from a wall socket or as a measure against obsolescence when the rechargeable battery eventually wears out.
Our favorite feature of the RDP-XF100iP is its sound quality, but we'll get to that in a minute. Compared with other portable speakers, the one feature that really sells the RDP-XF100iP (aside from its sound quality) is its FM radio. Our Editors' Choice Logitech S715i offers a better price and a more compact design than the RDP-XF100iP, but it doesn't offer a radio. The Altec Lansing InMotion Classic has the radio, but lacks the sound quality. You could jump up to a serious boom box like the Altec Lansing Mix, but then you're losing the compact design. The Sony RDP-XF100iP sits right in that Goldilocks zone of price, sound, and portability, and if you consider FM radio a necessity, it's a great choice.
Another little feature we're happy with is the inclusion of a remote control. The remote has all the functionality found on the top of the RDP-XF100iP, and actually responds a little faster than the button controls. The range of the IR remote isn't great, but you can expect the typical 15- to 20-foot distance.
The RDP-XF100iP is a testament to Sony's reputation for sonic innovation and sound quality. It's not the most balanced or restrained system, but if you want an impossibly big, rich sound from a compact system, the RDP-XF100iP is tough to beat in this price range.
The RDP-XF100iP's biggest sonic trick is its guttural low-frequency punch. Right out of the box, with EQ flat on our iPod, basslines and kick drums fill out the mix in a dramatic and unexpected way. We imagine that Sony engineers must have pulled this off using some creative speaker porting or a passive radiator, because the low-end sound has a similar acoustic quality to the Yamaha NX-B02 or Kicker systems.
If you do decide to sweeten the sound with some of the integrated speaker EQ, expect that you will hear a little low-end distortion at high volumes, but it's nothing unlistenable. Overall we're impressed by how loud the RDP-XF100iP is able to get, even while running from its internal battery.
Battery life is rated at 7 hours from a full charge, either listening to the radio or an iPod or iPhone. By comparison, the Logitech S715i delivers 8 hours of playback time, though the audio quality takes a hit when it runs off batteries; the RDP-XF100iP maintains an awesome sound on or off its power supply.