Altec Lansing BB2001 Subwoofer
One of the problems with portable iPod speakers -- and I'm referring to truly portable systems that fit in your suitcase or carry-on, not "transportable" systems that would count as a carry-on by themselves -- is that you sacrifice full-range sound for portability. These smaller systems use 1" drivers, give or take a half-inch, and small enclosures, so they just can't produce real bass.
Most travelers are willing to put up with such a sacrifice when on the road. But when they get home, they have higher expectations -- leading many iPod owners to purchase a second speaker system for home use. But if you've got certain Altec Lansing speaker systems, the company has a less expensive alternative: the BB2001 Subwoofer. The self-powered BB2001 is designed to connect with Altec Lansing's inMotion iM5, iMX2, and iMT1; the XT2 Laptop Audio System; and any other new systems with a subwoofer-out jack. When connected, the BB2001 extends the speaker system's response, allowing it to reproduce much lower frequencies.
The BB2001 is self-powered, plugging into any standard AC outlet. An included 9.5-foot cable connects the subwoofer to your portable system. A power/level dial on the back of the sub lets you adjust the sub's volume to match your portable system; once set, the subwoofer's volume level automatically scales with the portable's volume level. (A blue LED on the front of the unit indicates that the BB2001 is powered on.) Finally, a phase switch on the back of the sub lets you reverse the subwoofer's phase; this can be useful if the sub's placement in your listening room results in bass response being out of phase with the portable system's own output.
At just over 9.75" high by 5.75" wide by 9.5" deep, with just a 4" driver in a ported enclosure, the BB2001 is small as subwoofers go. But keep in mind that the systems the BB2001 is designed to accompany themselves have very small drivers (generally 1") in very small enclosures; in other words, the main systems don't produce any true bass, and very little upper bass. As a result, when you connect the BB2001 to one of these systems -- I tested it with Altec Lansing's inMotion iM5 -- the difference is dramatic. As promised, the BB2001 adds a thumping low end to the otherwise bass-free systems it's designed to enhance.
On the other hand, because the BB2001 uses such a small driver, it can't reproduce the lowest frequencies; its purpose is to enhance, not complete. And -- also due to its small driver -- the BB2001's own frequency response extends up into the "placeable" range. That is, a true subwoofer limits its output to those low frequencies that have few directional cues -- it's difficult to figure out where the subwoofer is placed because you can't identify the direction from which the bass notes are coming. The BB2001 reproduces frequencies high enough that you can locate their position fairly easily, so you'll want to place the BB2001 near your portable system -- preferably just underneath or next to it.
The BB2001 also suffers a bit from the fact that it's designed to be used with a range of Altec Lansing portable systems, none of which has the same frequency response, yet the sub doesn't provide an adjustable crossover (the upper frequency at which the sub stops producing audio and lets the main system take over). Because of this, you don't really get a smooth transition between the sub and the main system. For example, when used with the iM5, I heard a clear gap between the BB2001's upper end and the iM5's low end.
That said, if you've already got one of Altec Lansing's compatible portable systems, the BB2001 will significantly extend that speaker system's low end for a very reasonable $50, giving you compact audio on the road and something approaching full-range sound at home.--Dan Frakes
Altec Lansing BB2001 Subwoofer
Small subwoofer that connects to Altec Lansing's compatible portable speaker systems to enhance bass response.