Review: Pioneer A4 Wireless Speaker Page 2
55 Hz to 20 kHz ±4.6 dB on-axis, ±4.9 dB avg 0-30°
87.9 dB at 40 Hz
To measure the quasi-anechoic frequency response of the A4, I set it atop a 2-meter stand and placed the microphone at a distance of 1 meter, directly in front of the left tweeter. (Quasi-anechoic measurements eliminate reflections from surrounding objects to simulate measuring in an anechoic chamber.) I measured the bass response using ground-plane technique at 1 meter. To create the graph shown here, I spliced the bass response below 200 Hz to the average of quasi-anechoic measurements of the left channel only taken at 0°, ±10°, ±20°, and ±30°. I used a Clio FW analyzer in MLS mode for the quasi-anechoic measurements and log chirp mode for ground plane, feeding test signals into the A4's 3.5mm line input. The quasi-anechoic measurements were smoothed to 1/12th octave. The blue trace shows the 0° on-axis response, while the green trace shows the averaged response.
The A4 clearly has a downward-tilted tonal balance. But boy, is it smooth from 200 Hz to 2 kHz. Above that things get a little rougher, probably due in part to internal reflections between the front baffle and the grille, but the largest anomalies are above 6 kHz, high enough in frequency that you probably wouldn't notice them much.
I made the bass limits measurement using CEA-2010A technique, and did the measurements at 1 meter because personal audio products like the A4 typically don't have enough output to get a measurement at the usual 3 meters. Bass output is impressive for a product of this type, easily measurable down to 40 Hz. -Brent Butterworth
The A4 packs a surprising amount of performance in a small package. With all the attention paid to making it easy to connect, and all the multiple options therein, it would be easy to assume there had been no attention paid to sound. But Andrew Jones works his magic again, and this thing actually sounds really good. Color me impressed.
The A4 has two smaller siblings, a portable, water resistant version with a battery (A3, $400), and the A3's non-battery powered twin (A1, $300). Both of these lack the A4's 4-inch subwoofer.