The performance of the Phonak Audéo PFE232s was tested on a few different rigs to see how they perform under different conditions. The test setups were as follows: iPhone 4 - Headphone out, iPhone 4 - Digital out - Fostex HP-P1, iPhone - Digital out - Fostex HP-P1 - RSA "The Protector" (In-ear amplifier). A brief test on the HiFiMAN HM-801 with GAME-module installed was also conducted. The difference in sound was mostly due to changes in source, the amplification needs of the Phonak Audéo PFE232s are easy to meet, despite their somewhat lower sensitivity and higher impedance than other high-end in-ears.
One of the major benefits of the Audéo PFE232s is that you can swap out the acoustic filter that sits at the end of the sound tube. Phonak supplies three different filters that change the flavor of the sound. The grey filters are regarded as neutral in the sense that they do not dampen the high-end much. The black filters give a more smooth sound because they reduce the treble energy and dampen the upper midrange to some extent. The green filters change the in-ears to a set of very soft sounding bass heavy in-ears.
The interesting thing about the filter implementation on the Audéo in-ears is that they change the frequency response noticeably without impeding sound stage performance or the perceived speed of the presentation. The in-ears never sound muffled or congested even with the green filters installed. This is quite a feat, and the fact that the filters are easy to swap makes it easy to find your preferred sound signature. The filter system works way better than what we saw on the now older Sleek-Audio SA6s, not only mechanically but also in the sense that the in-ears do not change character completely based on what filter is installed.
With the grey filters installed the PFE232s sound energetic and balanced. The treble has sufficient energy to engage you, and the upper midrange is without any nasty bumps which makes them sibilance free on well mastered recordings. The sound of the PFE232s can best be described as balanced with slight emphasis on the bass and treble. The Westone 4s have a bit more forward midrange, and dominant bass. Midrange wise the PFE232s with the grey filters remind me of the Ultimate Ears In-ear Reference Monitors (IERM) with just a tad more warmth. The detail level is up there with the Westone 4s and it is pretty close to what the IERMs can produce.
The black filters give the PFE232s a slightly smoother sound that is very pleasant to listen to. The bass is given a nudge and takes a little more focus than with the grey filters, although nothing dramatic. The green filter gives the PFE232s a mellow type of sound without it becoming too dark. All of the filters add their own touch to the PFE232s sound, but they never ruin anything.
Sound stage wise is where the PFE232s are lacking compared to the rival products. The Westone 4s and 4Rs manage to produce a more coherent sound stage that is slightly bigger and more three dimensional. The PFE232s just cannot deliver the same sense of space as both the Westone and the IERMs, no matter what filter and tip combination we tried.
The microphone and remote system on the PFE232s seems to work fine. As the rest of the product it is very well constructed and feels like it can take daily abuse without falling apart.