Pros: Clarity, Highs, Mids, Deep bass tones
Cons: Bass quantity, presence, sometimes slight silibance
I bought my 315s when I decided I needed some "pro" headphones instead of the continuous cheap ones I kept finding around. I bought them at guitar-center for $200 with $20 2 year warranty. I have spent a long time using them (4 months) and never reviewed them because I was not quite s(h)ure what I was missing. Recently I acquired a pair of UM3x that I love too so they set the stage for me to judge the SE315s properly.
First off I find the SE315s very underrated here at head-fi. Frankly when looking for suggestions and such no one was suggesting the 315s - people were even like "315s are meh". I dont understand why - compared to most single balanced armature drivers I find these much better. So if your looking for a well rounded IEM to get into the world of hifi then these are not a bad start.
Price: I found these to be a little expensive but I wouldn't really regret purchasing them. The extra insurance was not needed considering the build quality.
Build: They are like sexy little tanks when you hold them. I feel like you could pull the costa concordia out of the sea with the cable alone. The removable cable connection is all gold plated and very solid. The IEMs themselves are 2 cases. The armature has its own solid plastic case then a second case surrounding the whole thing. The solid-wire in the part that wraps arround your ear did break for me but this wire only holds the shape of the cord. it does not carry sound. It was in a high stress location and was mostly my fault. Still functions properly though.
Science: Im no sound engineer but this armature looks much different than any of the others ive sen. Franky its much bigger and looks like it has some sort of dual plate system. I can also see the tuned bass port and frankly the transparent 315s are super cool because you can watch everything work (no excursion to see though. sad face)
Highs: They sparkle. They extend. They are clear. They are fabulous.
Mids: Emphasized and present. But not in a scratchy way. Makes me want to boost the High EQ usually. But thats okay, it sounds nice either way.
Lows: Lacking. I feel like it takes some persuasion to get them out, but when they come out they are there, controlled, and clear. They are fun to listen to and kinda dance around you - tempting you for a little more but I mean youll probably be content with some EQ. A huge boost to the low shelf of 32hz seemed to make it more fun. The mid-bass was okay to start with but the low lows are hard to find.
Stage: Sound stage is good. Nice separation and space. Compares well to my UM3x
Case tips / tool: The case is neat. Kinda soft but it fits my sansa, 315s, cleaning tool, small usb cord, and an extra set of tips very nicely. Kinda a cool portable setup. So after I got my 315s I let my borther try them the next night (he is 8 - has waxy ears)... TLDR he clogged them with wax. There was virtually no sound coming from the right. Scared me senseless. I took the cleaning hook and some peroxide and lucky for me they cleaned right up.
Isolation/Sibilance/CordPhonicsBlahBlah: Excellent isolation. I used these headphones to go shooting once. I took off the cable and stuffed the IEMs in my ears like you normally would and it made a very comfortable shooting experience. I was shooting 9mm (for sound reference for those who are familiar). Sibilance can be a problem on some soruces/tracks. Lowering the Tip top High EQ just a tap helped with this. Once again this was only a few times. As for what ever you call the thing where you can hear the cord rustling against you they suffer from this but its nothing that I would be put off by.
Overall im happy with the 315s. While I feel like they lack the bass they can certainly handle it when given. Thats what was so frustrating. They have awesome bass control but without some changed to your source youll be lacking bass. Combined with my EQed Sansa clip plus they sounded excellent. Despite having acquired my UM3x that are now my main headphones I will not sell off my 315s because they are just fabulous. They are good spares and I like letting my friends use them to listen with me. If you crave something with much bass you might want to look else where unless your only using an EQed source most of the time.