- Written by John E. Johnson, Jr.
- Published on 01 September 2011
On the Bench
The distortion measurements were taken at 2 meters from the center of the speaker. I was unable to get a reliable frequency response measurement due to the dipolar sound.
At 50 Hz and 90 dB output, THD+N was very high. I expected this because of the limitations of flat-panel speakers noted on the previous page.
However, at 1 kHz, distortion was very low.
And, at 10 kHz, distortion was also low. As I have previously stated, flat-panel speakers do very well in the high frequencies.
This graph shows THD+N vs. Frequency with 1 kHz set to 90 dB at 2 meters. Because of the dipolar nature, there is interference in the low frequencies caused by the negative wave coming out of the rear side coming around to interact with the positive wave emerging from the front side. It is particularly bad with the lowest frequencies, and I think that the distortion measurements at the low frequencies in this graph do not accurately reflect the true amount of distortion (I believe it is lower, as I didn't hear any noticeable distortion in the lows or mid/lows).
The impedance was as flat as I have ever seen in any speaker, and was nominally 4 ohms as specified. It dipped down to 2 ohms in the 10 kHz - 20 kHz region, so as I said before, don't use a mass market receiver with these speakers. The phase varied from + 60 to - 340, which is excellent.