So @CEE TEE came over one day with a bunch of JAR headphones. We both sat down and listened to each one of them and ranked them according to our own tastes. The whole session lasted roughly about an hour so we were speeding through it all. I remember myself saying that there was a pretty marked difference in tonality between all of them. Then we proceeded to measure and... it was honestly not as clear cut as it seemed. Please note scale. Frequency response basically told me all of these were tuned by exactly one person and they cared a lot about good measurements. If I was reading just those graphs blindly, I would not be able to tell them apart. Here they are again in isolation and with less zoomed in scale now to show just how linear they actually are on my EARS: My listening notes for them at the time were: JAR600: very even, if not slightly bright. Doesn't do anything offensive. Seems the most airy. JAR650: harder hitting, a wee bit more relaxed than JAR600 but still very airy. I like the bass here quite a bit. JAR660S: seems to have the lightest bass and also the most relaxed sound. Kind of not offensive but also not impressive at the same time. It's not doing anything wrong but also not impressive either. Between the 3 of them, I remember ranking the 600 as being the closest to neutral, 650 as being on the darker side, and JAR660S as being the brightest, surprisingly. But again, can't tell from FR. From FR, JAR600 should be the brightest, but it's not quite so. And 650 should not be the darkest, but... it's also not quite so. Oh, and at that time, we also had a 580 (stock-ish) and a 650 KISS-modded. Here are extra comparisons (only posting the ones that are worth noting) [ The 580 was... without a doubt, the brightest headphone at that time. The pads were in pretty bad shape so maybe that explains the sound? Overall it was just too bright and shouty for me. And yes, this was even brighter than the JAR660S. 650 KISS-modded wouldn't seem too different from JAR650 from measurements, but it was ranked as the darkest headphone of the bunch. Somehow the JAR650 sounded more airy and kind of tighter. Honestly, if I didn't already make my own HD800-based headphone, I'd definitely highly consider one of the JAR headphones here as a daily driver. What's been achieved here is probably much more than my brief impression with them can express.