Tom’s Hardware doesn't write about a ton of audio equipment, so we'll give you some background information to help make sense of the frequency response charts.
|Audio Test Equipment|
|Decibel Meter||CM-130 SPL Meter|
|Microphone||Apex-220 Measurement Microphone|
|Software||TrueRTA Spectrum Analyzer|
|Preamp/Audio Device||Tube MP Project Series|
|Measurement Setup||13' x 17' carpeted room|
Microphone Test Distance: 76 cm (30 inches)
Ideally, speakers are tested in an audio-neutral environment called an anechoic chamber. Our testing is performed in a lab. Because it's not an anechoic chamber, the room will affect the results to some degree. We'll identify some trends that persist across all of the tested speakers due to the environment, but our results are mostly relative, comparing the speakers to each other.
Here's a quick legend of the audio spectrum:
20 to 60 Hz: The sub-bass range. This isn’t heard so much as it's felt. Sound in this range provides a sense of power.
60 to 250 Hz: The bass range. This is where you hear the bass rhythm, especially in the 90 to 200 Hz area.
250 to 500 Hz: The lower midrange. It’s also called the bass presence range.
500 Hz to 2 kHz: The midrange. This is where you hear instruments and vocals.
2 kHz to 4 kHz: The upper midrange. Higher instruments and most vocals are heard here, and the human ear is very sensitive to changes in this range.
4 kHz to 6 kHz: The presence range. Too little sound in this range will make the audio seem like it’s coming from farther away.
6 kHz to 20 kHz: The brilliance range. This is where you hear harmonics and clarity, and accented sound in this range will make it seem crisper and clearer with higher fidelity.
Armed with this knowledge, here are the frequency responses of the speakers in our round-up.
Generally speaking, it appears that our lab causes a gradual dip from 200 Hz down to 1 kHz, and then back up again at 5 kHz. With this in mind, let's consider the results.
First, we'll concentrate on the ultra-portables: the Arctic S113BT, Luxa2 Groovy, and Edifier Extreme Connect. Starting with bass at 50 Hz, the Groovy shows an advantage in our test environment. By 100 Hz, the Extreme Connect catches up. Given these results, it'd appear that Arctic's S113BT suffers in the bass department, and that's exactly what we reported from our subjective testing. The lines come closer in the rest of the spectrum, but Edifier enjoys the flattest response overall. Luxa2's Groovy spikes in the upper midrange, but drops off fast in the brilliance range, while Arctic's entry delivers a bit more after 15 kHz.
Next, the portables from Cambridge Audio and SuperTooth. The Minx Go delivers an impressive performance starting at the bottom of the bass range and continuing up to the presence range at 5 kHz, where it suffers a few bumps. The SuperTooth Disco Twin looks inconsistent in comparison, with good low-end response followed by a significant midrange dip and then a drop in the presence range starting at about 4 kHz.
Finally, we have the big guns: Eton's Ruckus XL and Logitech's UE Boombox. The UE Boombox looks good, but you see how the massive bass can overpower the rest of the spectrum, which is admirably flat. As for the Ruckus XL, it sports a nice, even response, except for a strange peak in the 9 kHz range.
All of this objective data supports our own observations, so we're happy to have a chart that doesn't toss a handful of surprises at us. We'll move on to measuring the maximum volume each speaker system outputs.
It's interesting that Luxa2's Groovy and Arctic's S113BT deliver lower maximum volume using the 3.5 mm input, rather than Bluetooth. Otherwise, the only other interesting observation is that the Groovy can get so loud, despite its tiny dimensions (at least through its wireless connection).
Now for a look at Bluetooth reception range.
There's a big difference between Bluetooth implementations. We're not surprised to see the larger options performing so well. However, we weren't expecting SuperTooth's Disco Twin to lead the pack, tied with Logitech's UE Boombox.
Next, we put battery life to the test by emulating an indoor workplace. Each speaker is 20 inches (50 cm) from the listener, broadcasting a Songza playlist, and producing about 46 decibels of sound pressure.
While the ultra-portables tap out around five or six hours, SuperTooth's Disco Twin manages eight. Logitech's UE Boombox keeps the music going for 11 hours, while Cambridge Audio's Minx Go and Eton's Ruckus XL each come close to hitting a full day of playback. Battery life will go down as the volume goes up, of course.
Finally, let's consider the built-in microphones for hands-free mode. This test is limited to the ultra-portables: Arctic's S113BT, Luxa2's Groovy, and Edifier's Extreme Connect.
Arctic's S113BT gives us the loudest and brightest response, but not the clearest. The Groovy cuts out a lot of noise at the expense of volume. Edifier's Extreme Connect sits somewhere in the middle.