I measured the Audéos using a G.R.A.S. Type RA0045 ear simulator, a Clio FW audio analyzer, and a Musical Fidelity V-Can headphone amplifier. I used the medium-sized silicon tips, which fit the ear simulator best. I inserted and reinserted each model several times, and settled on a position for each that gave the most representative result.
To gauge the differences in the headphones’ response without incorporating the differences caused by the filters, I measured all three with the gray filter installed. The PFE 012 and PFE 132 have nearly identical frequency responses. The PFE 232 is much different; it shows a much stronger balance of treble relative to midrange, and of course a much stronger bass response. No wonder the PFE 232 doesn’t sound good with the black and green tips.
I also measured the effects of the filters, using the right channel of the PFE 012. The filters seem to function essentially as a midrange control, with the strongest and flattest midrange response provided by the gray filter. The black filter cuts the mids by about -6 dB, and the green filter cuts them by approximately -12 dB.
Because of the impedance variances at high frequencies (see impedance results below), all three models showed some frequency response variance when I added 70 ohms output impedance to the V-Can’s 5-ohm output impedance to simulate the effects of using a low-quality headphone amp. With the PFE 012 and PFE132, treble is boosted by about +2 dB, which isn’t terribly significant. However, with the PFE 232, treble is cut by 4 to 7 dB when a high-impedance amplifier is used. It might be a good idea to add a separate, mini amplifier when using the PFE 232 with a laptop computer or a smartphone.
Distortion is very low for all three models, even at 100 dB (level measured with pink noise, A-weighting). Total harmonic distortion (THD) is lowest for the PFE 232. The PFE 012 THD shows a mild rise to an average of 3.7% THD between 1 and 2.8 kHz, and an average of 4.7% between 2.8 and 4.7 kHz, but this is at a pretty high level. I didn’t show a chart for 80 dB because THD is negligible at that level.
All three Audéo’s show a major impedance swing at high frequencies. The PFE 012 and PFE 132 run around 32 ohms below 1 kHz, but rise to 80 ohms at 20 kHz. The PFE 232’s swing is more extreme: It starts off around 40 ohms but plunges to a low of 12 ohms at 8 kHz.
Isolation measures about the same for all three models, but in all cases better-than-average for an IEM. Significant reduction starts above 100 Hz, and reduction runs from -10 to -35 dB through most of the audio band. Isolation results will vary with the tips you choose, the shape of your ear, and how tight of a fit you like.
Average sensitivity from 300 Hz to 10 kHz with a 0.179 volts RMS signal and the factory-installed filters is 98.2dB for the PFE 012, 104.5 dB for the PFE 132, and 101.8 dB for the PFE 232.
All of the Audéo models have their own appeal, but I find myself narrowing my recommendations down to the PFE 012 and the PFE 232.
Get the PFE 012 for $119, add a box of eight black filters for $19.90 and a $6 case, and you’re got yourself one hell of a great set of IEMs for about $145. You can also add the cable guides if you like, or spend an extra $10 for the mic-equipped PFE 022. The PFE 132 is nice, but I don’t see an extra $94 of value there.
The PFE 232 is undeniably pricey at $599, even with the free $129 PFE 022’s thrown in. In comparison, Westone sells a dual-armature IEM with removable cables, the UM2, for just $299, although the UM2 doesn’t have interchangeable filters. Unfortunately, I have heard the UM2 only briefly so I can’t say how it performs compared with the PFE 232. Still, I have greatly enjoyed the sound and comfort of the PFE 232 and I suspect most people would share my opinion of it.
Brent Butterworth and Geoff Morrison combine their years of gear testing and knowledge in one überblog of irreverence and techiness.
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