I think I have settled on the pfe232. The main reason is the impedance differences. My ipod touch or even a classic, which is where I spend most of my listening time, is the most "dull sounding". The 32 ohm duet boosts the treble, however, in the same way accudio reduces the bass/mid bass to make the set more neutral, the treble boost of the duet has the same effect.
In fact it's almost half way between the ipod touch signature and the accudio "hi-fi" flat signature. Nonetheless, on the ipod touch without eq or accudio the sound is fairly "dull". It is flat in the sense that all of the frequency regions blend very smoothly into each other and there is nothing offensive. It is very nice sounding as well, but it doesn't sound flat. It sounds flat-like, but with a lack of realistic treble. The treble is too soft and it sounds like the treble have padding on it softening it. This is the best lack of treble I've ever heard though. Ha. It sounds great and smooth still and reveals great details.
However, when you apply accudio, the treble opens up and the bass sounds more distinct. I believe it is a little "too" bright with accudio personally but only by a small amount. According to their graphs and changeability scale, the 4R isn't perfect after accudio is applied. There is still a slight treble bump in the middle of the treble, which is probably the "slightly too bright" sound. However, I wouldn't take any other setting over how good it sounds with accudio. Treble bump is better than treble padding to me. It isn't harsh or offensive, it just sort of takes the forefront of the audio by a very small margin. Overall, with accudio though, the sound is very flat in general, much more distinct instrument separation from the eq changes. Things "come to life" and open up. Very nice. Kick drums become tighter and kickier. You hear more air in the soundstage. Very nice.
However, the pfe has a lot of these attributes without accudio. And they scale much better accross impedance sources. The duet lowers the treble a bit, but by a smaller margin. You could almost argue it makes them more flat even, which isn't really bad. But on the ipod the treble is excellent and they sound "lively" and "open" with no modification. Accudio also has a better adaptability scale rating for the 232. I assume this is because they don't really lack any frequency production in the first place, so it's easier to reduce the humps than it is to make up the dips in the 4R. So overall, the pfe232 is even more flat with accudio.
So for me personally, here is the rundown
- More lively
- More open
- Better bass in general
- Scales better (less difference) with impedance changes
- Requires less eq/modification to sound great "out of the box"
- Less mid presence "out of the box"
- Smoother "flatter" transition between frequency ranges
- Better mid range "out of the box"
- Dull sounding on low impedance sources
- Scales o.k. with impedance changes, but actually improves with higher impedance sources to some degree/limit, which isn't really a plus as portable devices are aiming for low impedance
There are other factors as well, but in terms of audio, I'm finding the pfe 232 fits the bill better overall. I'm giving it one or two more days, as I really want to break in my brain with the 4R, but I think I'm pretty much set.