Since you're into car audio here's a very rough guide on what sounds like what to give you some kind of an idea, although I haven't been checking car audio these days (I've been using Uber and catching up on sleep). Assume proper amplification, installation, and no EQ fine tuning unless otherwise stated. HE400i/HE400 - Imagine most cars tuned for EMMA SQ, but the vocals aren't very clearly forward; 10in sub somehow installed up front or in the center console with a lot of air space (or sub requires very little) but gain tuned to just catch the roll off at the low end HD600/HE400S - Focal Polykevlar midwoofers with TN90 tweeters, with more bite on the electric guitars on the Sennheiser; sub in trunk in compact box HD650 - Focal Polykevlar midwoofers with Vifa tweeters, running full active and set the preamp gain and amp gain for the tweeter channels lower. LCD-2 pre-Fazor - DLS MS6 with a 12in sub in a sealed box, equalized sub gain LCD-2F - DLS UR6.3 with 12in sub in a sealed box, equalized sub gain K701 - Dynaudio 6in set with 8in sub in a sealed box with not a lot of power from the sub amp in the trunk K702 - Dynaudio 7in set with 8in sub in a slightly larger box and more powerful amp Grado SR225 - Focal Polyglass with powerful amp but getting low imaging scores for crappy install Grado SR325 - Focal Polyglass with powerful amp but low imaging scores and tweeters really bouncing the treble off the windshield What do you mean, over the ear? The earpads go around the ears, earcups are on "top" of the ears. That still depends on the size of your earlobes though. And why Sennheiser made some headphones oblong (HD580/6xx series) and newer headphones enormous as they grew longer downward and wider forward (HD800 and HD700). As far as I know, yes. The plug on the headphone or rather the part of the cable near the plug is where it usually breaks, unlike older Sennheisers that easily break the locking mechanism on the socket. I actually would get the HE400i for the newer headband. I only brought up the HE400 in case you're buying that used but maybe you can wait for it to come back on Massdrop. I wouldn't use "underspec'd." That sounds like taking a current system and hamstringing it, like how older Streetfighters were basically the Superbike without fairings and then they put torque-priority cams in the engines and a flatter seat (unlike the Ducati Streetfigher, which is literally the 1098 Superbike without the fairings). More like they necro'd an older product.