- Written by Jim Clements
- Published on 31 July 2013
The PSB Alpha PS1 Speakers On the Bench
All the below measurements were taken in-room on the left speaker. I placed the speaker on the top plate of a heavy stand for the testing. The frequency response tests were performed at 1-meter while the distortion measurements were on-axis near field measurements with the microphone 1' from the center of the driver under test.
The on-axis response of the PSB Alpha PS1s shows an exceptionally flat spectrum from 80 Hz to 18 kHz. There are room-induced fluctuations in the bass below 250 Hz.
At 30 degrees off-axis, the PS1's had a response curve that was in many ways smoother than the on-axis test. The treble even extends better to 20 kHz. This quality is probably what promotes such great imaging as I discussed in my foregoing analysis. I don't know how the engineers at PSB were able to pull this off. Finally, the bass showed a little more unevenness on this test.
The THD at 1 kHz and 90 db was 0.32%, with the first harmonic more than 60 db below the test signal!
At 5 kHz and 90 db, the THD measurement was 0.45%. The first harmonic is more than 65 dB below the fundamental! This is a very clean test plot.
Similar results were measured at 10 kHz and 90 dB.
At 250 Hz and 90 db, the distortion was amazingly low at just 0.18%. The first harmonic is also 60 dB down on this test plot.
The PS1's did not extend much below 80 Hz, but the distortion measurement at this frequency and 90 dB was more than acceptable at 3.12%. This is excellent performance from a single 3-1/2" woofer and 20 watt amplifier.