Originally Posted by stationwagon
I Believe you are wrong, and it does exist, the main reason to point it out is because my friend tested both, and he could clearly state that the w4 Had one stronger driver, while the w4r were neutral all the way, which means both were accurate to the same level, while some may not notice, it will be a prominent issue with the drivers only when your listening at a moderate to mid level, and it is proven on the above video I posted where he speaks of the driver matching.
The Acoustic Symmetry thing is stated to match each earpiece at +/-1dB. But this doesn't really mean that the W4s can't have this. In fact, they had probably meant that they did check for the W4R more carefully, and that the W4s had more variance. Not to say that the W4s can't be matched perfectly, just that they aren't as consistent. If you still have both on hand right now, I would really like to see some blind ABX tests/volume level measurements to reaffirm this. You would probably be one of the first to do so!
As an aside, I just attempted to measure the volume on each individual earpiece with some cardboard, foam, and a SPL meter. While not entirely accurate by any means due to the nature of the gear, they did manage to stay within +/-1dB of each other from what I saw. Maybe I got a good pair?