So I heard these yesterday. Or at least some sort of prototype. Pioneer rep said they were still being fine-tuned and that the sound signature was "80 % there". Supposedly, the finished version was going to have, among other things, more bottom end. That statement surprised me, because, out of my Sony WM1A, I didn't think they lacked bass. I rather found the lower range to be a bit boomy and protruding into the mids. Lower mids and bass altogether too upfront for my taste and sort of unrefined. Unfortunately, I didn't find the highs that great either which sometimes tended towards the harsh and metallic side.
I was afraid beforehand that I'd massively regret having bought the Z1R before getting a chance to listen to these, but as closed cans go, I think I prefer the Z1R (then again, it costs twice as much). The Monitor5 had some heft to it and sounded very present, but also seemed muddier to me than the Sony and actually reminded me more of the Technics EAH-T700, which I wasn't too keen on for similar reasons. Comfort is decent. Isolation not stellar, but okay while music played. They come with three cables including balanced, which is kinda neat for the price.
Later in the day, I heard another Monitor5 in a "headphone bar" setup, and for whatever reason I felt a tiny bit more forgiving towards that unit. Problems seemed to be the same, but a fraction less annoying. If that was due to a different chain (components were hidden, but likely something chunkier than just my WM1A) or to "burn-in" or to me having already been acquainted with its shortcomings, I have no idea.
As said, please take these quick impressions with a huge grain of salt, as changes are apparently still being made. (The rep actually said with a wink that they were absolutely fine with the competition thinking it sounded like this, and that they only showed the Monitor5 in the first place because it had been "leaked".
He also mentioned that they are now going for a June release, IIRC.)
Also, my WM1A might not have driven them properly. I had to put it in high gain and almost maxed out on the volume anyway.
I guess my expectations were a bit steep, because I hold the SEM1 in very high esteem, and while what I heard was certainly not a bad headphone in absolute terms, the magic just wasn't there for me. In any case, I'll definitely check out the finished product if only to see what changed.
