ASUS Wireless Portable Stereo Speaker (SP-BT23)

Combining wireless connectivity, a high level of portability and decent battery life, ASUS' SP-BT23 speaker is a decent option for listening to music indoors or outside. Its sound quality leaves much to be desired, but it is very convenient.

The SP-BT23 offers analog sound through a standard 3.5mm jack and Bluetooth support with Advanced Audio Distribution Profile (A2DP) capability. It can be powered by either a 12V adapter or four AA batteries. The speaker is coated in gloss white plastic, with black plastic surrounding the woofers. At 123.5mm, the SP-BT23 is quite tall for a portable speaker.

During transport, the SP-BT23's dual 1in woofers are protected by a plastic cap with a removable rubber insert. When using the speaker, this cap can be placed on the bottom of the speaker to aid the ported subwoofer. Unfortunately, there is no grill or similar protection for the woofers when the cap is removed.

The slight curvature of the case near the woofers allows the speaker to sit flat or be stood upright.

The environment and placing the cap on the passive subwoofer (or not) affect the sound quality and frequency biases of the speaker.

When placed in its most logical position — standing up with the provided cap placed on the bottom — the SP-BT23 has a slightly tinny sound, and no real lower mid-range or bass frequencies. Standing the speaker up and facing it towards a nearby wall makes the sound much more biased towards bass. The SP-BT23 doesn't provide the best sound quality, even taking into account its size and price, but its design helps it take advantage of its surroundings to improve audio.

The SP-BT23 is highly portable and has a long battery life. When testing the speaker at the loudest possible distortion-free volume level through the 3.5mm cable, the SP-BT23 lasted a total of 18 hours; this falls short of Altec Lansing's orbit MP3 (IM237) but is still commendable considering the speaker's size. Equally surprising was the device's ability to play streaming audio from a Bluetooth device for a total of 15.5 hours.

The speaker's Bluetooth connectivity works quite well. Pairing the speaker with a notebook or mobile phone works just like Bluetooth headphones, simply requiring users to put in the default PIN code and change the audio settings if necessary. The SP-BT23 can be placed up to 15m from a paired device, though walls and obstacles will affect the maximum possible range.