I figured I'd do an off the beaten path on a device I've had since about '09/'10!
I'll keep it short.

It's a simple media player capable of powering budget IEMs and things of that nature. If you ever considered getting one I'd certainly recommend something to power other headphones.
The things it powered without any problems that I tried were these.
-Shure SRH440
-AudioTechnica ATH-IM50
-AudioTechnica ATH-M50
-KZ ATE
-KZ ZST
-KZ ZS3

I'm just gonna give you a rundown of my experiences with the Creative Zen MX.
I use/used this sometimes when I don't have enough storage on a MicroSD. I use a secondary card with my other albums, artists, etc.
It's done me well lasting this long as when I was younger and it's survived being ran over by a car when I was stupid at the time and let it fall from my pockets.

Battery life is generally stable with given use. It not being a touchscreen device probably adds to its battery being so extensive counted with the fact that low display lighting is easy to see in midday conditions making this device ever so useful.

My conclusion simply sits like this.
If you need something cheap for a child, sibling, or anyone as a gift, finding one of these should be easy.(?) Not too sure.
As an on the go device, my usage and story should be a slight demonstration as to how reliable it is, though I don't recommend sticking it under a car tire for a proper pressure test. Daily usage, sure! I still go back to this when I'm on the go as I carry lots of items with me to keep me entertained, this comes into use when I need more music.
Grab it if you can find it, use it until it breaks!

MEElectronics/MEEaudio
Introduction
My experience with IEMs is short lived, but I've had fair enough experience to give you proper detailing.
I mainly use detachable only, and can report from multiple detach period with the M6 they don't have an issue being pulled apart.
 
-Details 
-Sub Bass
-Shiny/Glistening Highs
-Detail In Mid Rhythm Section
-Bass is Deep, right seal needed to achieve proper Bass Reponse.
-Sparkling Shiny Highs
-Acoustic Separation
-Piano Detail
 
 
 
Driver Specs
[driver type    moving coil (dynamic)]
[driver size    10 mm]
[frequency response    20 Hz to 20 kHz]
[impedance    16 Ohms at 1K]
[sensitivity    100±3 dB (1mW at 1KHZ)]
[maximum power input    30mW]
 
 
Microphone Specs
[directivity    omnidirectional]
[frequency response    100 Hz to 10 kHz]
[sensitivity    -42dB± 3dB]
 
 
 
 
 
 
--Comfort--
Comfort with this IEM is unforgettable, during the first day I received them I actually kept them in the whole day, and would only pull out one just to keep with a conversation.
They are soothing, and comfortable, and quite easy to forget about if you can't tell the difference in muffled sound while something is in your ear.
 
--Notes For The Skeptical People(If you're considering buying it, I recommend you read over this)--
These are just some important notes for people who are worried, or are trying to understand the sound more.
The M6 Pro is Accurate, Has Clean Bass, & Highly Detailed for it's asking price which is something you won't always get in this price range. 
Accuracy ranges from the spot on guitar lines, to the punchy non textured, deep, laid back bass.
Separation is good, but I think the way it's separate is what makes high notes come off sharp sounding, and maybe piercing.
 
For the price, you really can't beat this if you're looking for something accurate, detailed, or something to use while you're on stage.
The M6 Pro has a very High Fidelity sound!
I'd recommend ignoring anyone who comments on Bass, as the driver changed sound as you listen to it more.
 
--High Note Info--
These are a bit glistening in the highs, and some may refer to them as piercing, which be it, unfortunate.
The tinging you get from most Open Back, or well derived Closed Back doesn't remain to be a thing here, though arguably Cymbals, Brass, & other Metal, Nickel, & Brass based instruments will be a bit on the Bright Sounding side and crush with the Treble causing what's normally classified as Hot Treble Sound.
EQ'ing will work this out, but tends to ruin the genuine definition of what the monitor is meant for.
 
--Bass Notes For People Who Love Bass--
I mentioned ignoring comments on this IEM that claim it has no Bass. And I stand by that.
If you want a few good tips on achieving Bass Structure, find an EQ you like that has the Bass Resolution you like, and let it burn in to the M6 Pro for at least 24 Hours.
Doing this has helped buff Bass.
For standard users who want a little Bass, the extension is in the Monitor, and it sounds really deep, and lead on, but it helps with the detailing on instruments so that the emphasis isn't too focused on the lows.
 
--Clear Genre Responses--
I mention below that Jazz sounds precise, & gorgeous in these, and stuff with a more Acoustic, or Brass element may come of crisp, but lean, and not matured in the bass regions deterring others opinions.
Now I've commonly heard the comparison of these coming off a bit like the $150 Westone UM Pro10, and from experience with both it's very unlikely as people don't really care much for the tinny sound of the UM Pro10 and criticize it due to its bass response.
Which leads me into saying that the M6 Pro doesn't share much, only sharing kind resolution, and musical notes that give off a lively sounding feeling, as states the purpose, "Great for On Stage use".
 
--Build Quality--
The M6 Pro for being $50 is built VERY NICELY, and arguably better than the SE215, & IM50 which feels easily breakable under pressure.
 
--Looks--
If anyone is to find this topic important, the M6 Pro give off a gorgeous shimmer in sunlight, and make it pop out of a crowd.
They're very pleasing to look at, and gaze into and get lost. The drivers shimmer, to the true photogenic beauty of this IEM, you won't need to worry about a silly look factor, and if you don't wear hats, I'm sure you'll get glances.
 
--Soundstage & Separation--
Like most IEM Variants in this range, Soundstage is rather important to some people.
I feel the stage on this is a bit lacking for being such a beauty, and a musical piece to listen to.
I'd compare it to being on a small stage, and hearing everything around you at once, but not being able to move your head, so it's very compact. Though don't let that shy you away!
 
The separation factor is great! I refer to separation as being able to tell certain instruments apart from one another.
Due to the detail, and characteristics I've mentioned, this is really good at identifying things, I can call out the shimmer in a backup guitar, and the fluidity of the bass lines being plucked!
I simply fell in love with this, and would relisten to some tracks just to admire certain pieces, bass lines, cymbal crashes, and pick them all out and glee over them.
 
Sound Impressions[Across 24 Hours/Live Active Burn In]:
 
[First 2-3 Hours]
The M6 Pro at first was odd putting into the ear, even after using the ATH-IM50, it felt like a learning curve.
To be honest, this IEM in general felt like a learning curve, but it pays off.
Getting used to the sound signature was easy, and I actually fell for the crushing treble like a girl to a hot male.
I've always preferred a bit of Treble, Accented Highs, & Airy Sub Bass that carries a little puff to it.
 
[6 Hours In]
The Treble is still spiking up in Rock tracks with heavy Electric Guitars, and causing the Bass to fall into place and come off Neutral Sounding.
After a good while of going through 100+ Tracks, it becomes pretty evident that this In Ear can be a bit genre picky to some people, and definitely shows its but to tell you that it's a Studio/Live IEM.
I've noticed a more analytical increase point in Bass Response, as the first listen the Bass Timing, & Accuracy was loose, and V-Shaped.
Bass really began to fill itself out around the 5-6 Hour periods. You definitely got a good sense of it loosening up, and could easily tell.
An odd noise may occur, and I think it's the driver warming itself and loosening up during burn in.
 
[7 Hours In]
The Treble gains control over itself, and isn't as widespread, & veiled which seems to had made room for clean instrumentation.
But over time you begin to  hear a small decay in the Bass Impact that it first had, it begins to mellow out to Background Bass, & Sub Bass.
 
 
[12 Hours In]
From what I remember, and what I noticed, the driver was getting a bit rugged, and handling more genres better than my IM50s', and I noticed more Brass instruments popping.
I would go as far as saying that around this mark, anything in a Jazz related fashion can sound a bit flat, & glassy but come off with great resolution while being precise, and sharing a nice "Aw" Sound that I found rather pleasing.
 
 
Unfortunately do to computer issues causing me not to hear things from plugged in devices, I couldn't complete my 24 Hour analysis.
And on this not I would like to mention to anyone looking for a fat, fast, & impacting bass response, you might wanna look at the IM50, or the SE215 in the $100 & Under Range.
 
 
 
Genre Notes(I don't feel this is properly discussed):
I want to have my own spike, or thing about my reviews that makes them come off as  "different", so I'll be adding this for now on.
 
Rap/Hip Hop - Unfortunately I found this genre to be a bit lacking in the impact that most Hip Hop/Rap fans tend to be after, quite often called Fun Sounding.
The monitor does it well, but doesn't push itself to what the genre, or song is this definition asks for and leaves a pleasant sound, but layer missing in the Upper Bass to make a song in this genre feeling personal, or something to bounce around to.
 
Jazz - As discussed, doesn't carry much Bass with the genre, and tends to follow more accent towards the Acoustic, & Brass elements while giving you a clear sound, and a nice detailed experience.
I can faithfully say if you're like me with your Jazz, and you like to enjoy it without a certain thick layer and can overpass a Bass element, you'll love these.
 
Post-punk - I generally listen to a lot of Post-punk, either be it in the Death Rock field, or from the Classic Goth Sound of something like Joy Division, I seem to love it all.
My remarks with this genre don't leave me excited, but leave me pleased as some artists in this field either add touches of Coldwave to give it a lonely, clear, misty feeling, or add static to make you feel as if it were old, & lost.
Coldwave elemental Post-punk sounded gorgeous, and didn't leave me asking what was missing. The Treble of the bud itself works amazingly with some electric fields, and fits kind to give you a sense that anything in this field hasn't provided to me before without sound Muddy, or Muffled.
Static elemented Post-punk came off a bit harsh at times due to recording, or sometimes came off as an over detailed work and easily wore my ears out.
It's OK, but if you have a lot of distorted music, I can't comment on how you'll feel with the end result, but definitely not a deal breaker.
 
These are the genres I felt it were necessary to discuss, as it's what I listen to.
 
 
 
Audio Format
MP3 comes off nicely, no matter the bitrate, this IEM can cover it up and make it sound classy, though High Level Audiophiles/Enthusiasts who search for error like myself will notice a bitrate fall, or bad recording.
FLAC came of as it should, like an HD Experience, but better sounding, and a lot more resolution, somewhat like the detail you'd hear from the atmosphere in a movie.
 
 
 
Test Tracks
DISCLAIMER - The songs I've chosen are what shined out to me, and from my personal music collection.
I list what pops about them, what made me select the song, and where it shines.
____________________________________________________________________________________________________________________________________
/First Listening Period/
Grouplove - Chloe[Heavey focus in guitar melodies]
Hatcham Social - Shut Your Mouth[The Highs really make themselves known]
Die Zorros - Paint It Black[Driver balancing demonstrations, shows what the actuator can handle under stress of multi genre changes]
Half Moon Run - She Wants To Know[Used this track as a reference point for checking change in vocal peak]
Purity Ring - Grandloves[First Electronic Indie track I decided to test for genre extension]
Cirrus - Stop & Panic[A good artist that easily shows the Electronic Impulsed Songs]
Factory Floor - Taxidermist[Displays Drum Imaging the way this IEM intends to, gives you a full ear sense of feeling]
Turbo Fruits - Mama's Mad Cos I Fried My Brain[I just really enjoyed the pitch in the highs, and that treble doesn't desolate]
/Second Listening Period/
The Deslondes - The Deslondes LP[A good Blue/Country LP that shows the display, and replacement of the Bass to include more instruments into the mix. Also, if you're a Blues fan, HIGHLY RECOMMENDED]

Small Talk Review:
Ok, so under heavy construction, office work, daily use, and all the things people do, Rubber Buds have failed tons of other people.
So Comply offers us their Foam Tips, with competition from others that aren't even as competitive in fair reasoning.
 
Sound Tampering 
I found something unsuitable to a bunch of listeners, and myself included!
With earphones, and IEMs with a sole signature of Warmth[Warm Bass Tone/Hot Splashy Sigs] they tend to really increase the thump, and sometimes splashy sound in these IEMs, which can cause a headache easily, or sometimes be a bit overwhelming. 
Now why do I complain about this? I think it's got something to do with the fit. The fit, and comfort with Comply Foams feels a bit more different than other foams I've tried.
Causing over-isolation, which isn't terrible! But it can be a constant distraction to be on your feet while in public, and also just plain irritable on Warmer Sounding IEMs.
 
Before I finish my small talk, I want to comment quickly on Cool Sounding IEMs quickly!
Cool sounding IEMs almost get a Treble fix? Odd. But Treble is near miniscule, and gives you a different perspective of a Cooler Sound, with a bit of impact, and slight increase in what seems to be a Hollow Sound.
Almost like a pole for example.
The sound is more compact, but it almost feels as if the Bass Impact gives you a fuller sounding punch, oddly... In a circle type sound.
I really can't describe it much.
 
Cleaning Talk:
So you're either me, in which you want to make something last as long as possible, or you're the average consumer, the guy who will bow to Comply, and constantly buy their tips.
 
Either way, a lot of cleaning tips I've seen do not go into much detail at all.
 
Two Methods!
Soap! - [Easiest way!]
My method on these is fairly simple.
1. Small bowl, any kind of soap without exterminate acids.
2. Warm, NOT HOT water! |Slowly whisk the soap around with your finger before the dip|
3. Apply the tips to the water WITHOUT FULLY SQUEEZING! You only want a miniscule amount of pressure applied by all means.
4. Gently rub your fingers over the surface of the soapy areas, dip in and out preventing too much soap from filling all the morsels of the foams.
5. Use warm water, slow pressuring them, and moving your buds in and out of the water stream while rubbing your fingers on them to massage the soap out.
6.[Final Step] Grab a napkin, not a towel, or anything overboard. Rub the napkin over the whole tip, gently grasping all the water with the napkin, and moving the foams to different parts once the original spot sucks out moisture.
 
If this procedure is properly done, give them an hours to sit out, and apply them back on!
 
Hydrogen Peroxide - [Not The Safest, But This Is A Safer Way Than Most HP Methods I've Seen.]
1. Pour HP on a napkin.
2. Slightly, and gently rub the dampened spots on the foams, trying to the get the HP deeper than the foams surface.[Warning: If it gets deeper than the surface of the foams, and isn't taken care of quickly, the foams can potentially start flaking in the future, and leads to falling apart!]
3. Run WARM water, NOT HOT over the foams after the HP has been in for at least 20-25 seconds.
[This process may seem easy, and it is! But without the appropriate amount of pressure, and proper watch, it can go all wrong. HP has chemicals that can safely clean foams, but can also have issues if left in too long which causes them to dry out, and crust!]

Companion II Series I - King of $100 & Under Richness?
 
With Bose being well known, and being a household name in today's audio world, there's been a lot of hit and miss. 
Bose has also made big mistakes. *Cough* QC15-QC25 *Cough*
 
Though I think they're definitely a choice for the Two Speakers, & One Amp application.
 
Bellowing Lows, & a textured Bass thump through these very thoroughly.
Unfortunately, we see the loss of a lot.
Mids are great, Detailed, & Forward. Bounded to beat most in their range.
My issue with the Bass was it's response, it's got great accuracy, but the Basses thunder remained at the same tempo, leaving tracks that are usually filled to the T with High Hits, & Low Blows missing.
But if Brass were a thing that were ever taken into account, it'd be what the Bose Companion 2 Series I did best!
From the burst of the blow force taken to power most Brass pieces, to the echo of chambers it leads to extort the sound, you get it all. It's very Forward Sounding, Bright, and High Frequency Focused.
 
Timbre of Acoustics is something very prominent here! 
My take after having owned these going nearly on seven years, they still preform like powerhouses. Leading on over +400 Hours of Burn In. They originally require 100 Hours for maximum performance.
 
I think the chase for Bose's first lineup speakers that'd lead them on to their Third Series! Lays somewhere in the ballpark of this.
These are speakers of High Performance, but for anyone who loves music.
Not just Audiophiles, & Audio Enthusiasts, so we'll go about it by tuning the Acoustic Radius to allow maximum performance with detail through speaker that isn't even Amped.
Fit for everyone's ear, even a novice could plug these in and notice something different about his/her music.
 
 
I will say, use an Amp to clear out most Static from Low Quality Audio Files.

MDR-XD-150BK
Easily said, the Black Version.
 
#BIGBASS Before we get started.
 
Descriptive Review!:
Laid back, more like a "Cheap School" Headphone you'd see people use if you were to buy the white pair.
These carry so little that you forget about them easily, easy fit for most heads.
 
Sound quality has a lot of play in it, it's got a Giant Emphasis on Mid Bass that can become too big at times.
Temperature Signature is mainly a Relaxed Sounding descriptive.
No real Warmth, and yet no room for Highs, & Brightness with how thunderous they sound.
 
I'd compare these somewhat to the 7506 with their Bass Depth, since it carries so much.
 
Honestly, there's not a lot to say, and the reason I didn't enjoy these was easy! I'm not a Bass fan.
Given! These will WOW Beats Users.

IE80 - High End Earphones
I think there's a point to where you draw the line for a Price Point, this goes over that boundary and breaks the rules of it's price, which is unfortunate.
 
I feel something in this asking price needs to meet some standards, Comfort, Unique Sound, & Build Flexibility.
And I feel these don't cut it, the need to be charged within the $175-$220 range.
 
This will be a descriptive review!
 
Sound Overview:
From what I've gathered, I think these are good! But the Soundstage is completely overdone for an IEM.
I think this range needs to be for accuracy, not how wide we can get the stage, and where will the instruments connect.
 
Highs, Mids, & Lows don't connect. What do I mean?
Usually in Headphones, IEMs, & Earbuds in this price have a sound that usually blends.
I'd argue that this is Sennheisers quality and House Sound, sure. But it's wider than most of what I've experienced from their products.
 
Highs, Cymbals are a really important part of most Sennheiser gear. They always bring you a pushed Acoustic Atmosphere, and that's because they do it right, want proof? Orpheus.
The whole Drum Kit mangles the highs, with clangs all over... these are the perfect Jazz IEM. Rides fall apart with crispness, I've never heard such an In-Depth Shimmer of a cymbal crash.
Sibilance really isn't a thing, while other tracking monitors for this price almost carry too much Sibilance. 
Making these precisely good for Detail Freaks!
 
A full body is carried into these, with Foam Tips, the detail will master your expectations and turn them into something you might love.
Bass is careful, it not a thing that is pushed into these and you shouldn't expect a ton without foam tips.
 
 
All said and done. Detail Freaks with a burning for IEMs will love these, and Bassheads can enjoy the fun as well with some Foam Tips, all in all I want to rate this for it's price, unfair, sure? But I want to give this a solid 8/10

Color! Because I feel in the mood for it. No, not really, this is just for the comparison.
So, Red, & Green?
Red - Not For Me.
Green - Solid, & something I personally like.
 
Comparison is going to be the first part of this review.
IM50 vs IM02
 
IM50
- Comfort of tips, Thick Mids(Sometimes so thick sounding it they become congestive), Shell can be hard to fit in some ears
- Great Upper Bass response, Highs are light(You get the required ting, without piercing through other layers), Great Vocal Iteration 
 
Opinion?:
I feel these are a SOLID choice to anyone who's into spending $50 and being surprised. Some layers aren't as exposed as others which makes this hard to recommend to just anyone.
They feel solid, look solid, and are quite durable. Replacement cables can be found, and I'd highly recommend some if you wanted to color your sound a bit.
They go OK with an Amp. Personally at 10 Ohms I feel like they're being pushed enough.
If you wanted to use an Amp, I'd suggest the Mayflower Electronics CMOY Portable Amp, it'll increase the camber of the Mids and slightly helps redefine the Soundstage.
Great piece.
I recommend getting them as a "stay at home", or "bed bound" experience as the warm sound satisfies just that. 
 
IM02
- Comfort, A Bit Open, Bright at times, Flattened Low End Bass
- Acoustic lovers dream piece, Poppy Highs, Fantastic HiFi Mid Range
 
Opinion?:
SOLID, possibly the only way to give pure definition.
If I were asked by someone if they should buy the IM50, or the IM02, I'd have trouble though...
The Low End Bass may not be enough to cure what Bassheads like and isn't well rounded enough in general to be a Warmer Earphone like its younger brother, the IM50.
If I were approached in need of reason to chose them over the IM50, I'd go along with this.
 
The IM50 is Dark, Smooth, similar to the likes of the SE215 with a bouncy, robust, almost dark chocolate like warmth, it's bombastic, and shares the kind likes of a "fun" Earphone. Vocals are sharp! A killer Mid Range sound is complimented with almost fuzzier genres, leaving Hip-Hop out of the question, it can work, but it's not the IM50s' forte. 
Highs are there, but are drastically flooded out in genres that need that extra boost in the Low End Bass to preform. It's a risk if you want HiFi, but a steal if you like warmth.
 
Now the IM02, what's different?
It's an upgrade for an IM50 user, though nearing Mid Bright Sounding.
Highs are pitched for this piece. Why?
Highs come off beautifully, and I'd argue this heads into the HiFi level of things. Almost Monitor Earphones. Tings, shambling, riding, and withering Highs make this come of extremely dry.
 
As the IM50 is compared to warm, and east to melt dark chocolate.
The IM02 is just like Peach Mango, a tasteful Earphone, fulfilling enough for some Warm Sound lovers, juicy, almost mouthwatering quality to anyone trying to enter High End Earphones with a $100 puch.
As I said, Highs are pitched, they enter Mid Range HiFi Standards of this new era of Audio Standards.
They aren't as bombing or competitive with specific genres. 
I wouldn't argue this is full sounding, as the Mids are covering most of the ground for these with Bass Guitar lines mainly filling up the space. Classical works moderate for these and is a certain expression point for good trial music to test their Acoustic Surroundings.
Soundstage is something I could argue as accurate for this Earphone, not accurate to where band members would be standing, but accurate in coordination points to other listening devices with Open Range Soundstage.
Lows are BUMPY, and really that's the only way a friend, & I could describe them.
They aren't Bass Fulfillment Earphones, but give a thunderous Bass that's more like a rumbling than anything else.
 
Who would I recommend these to? I'd argue that someone who wants a Clean Monitor Sound might enjoy these.
 
 
Up next, Burn In:
 
Now I'm not gonna layer it into your skull if you don't believe, but read this otherwise.
 
Only Burn In with your Music Library!
I believe some people get too much placebo effect from trying to commit to a Burn In, using Pink Noise, then expecting better outcomes.
 
These Earphones will need a Quality Burn In nearing 100+ Hours Burn In for whatever you choose to buy.
 
IM50 Burn In Expectations:
Just expect a thump to the Bass. 
Relaxed High Pitch Frequencies that don't slam into your Eardrums.
Thicker Bass, a bit more surrounding, but a more rapid pace.
 
IM02 Burn In Expectations:
Highs become more mellowed out.
Brighter Mids, detailed almost Bright Sounding Guitar Play.
Crash Rides gain a bit of detail.
Drums become Highlight Points.

I've constantly said I wanted to try these.
I've seen the price tag stay at $200, and it's appropriate.
It's big, but has elements.
It's sound is stand out, Class A, $200 Sound.
 
The AKG K550
I've been wanting to try these since I seen the price tag, after searching for an upgrade, looking at the MDR-7506, and seeing these side by side, the MDR-7506 is OK, but has a purpose. It's a Studio Monitor, that's it's justice.
The AKG K550 is an important piece in it's price range, and it reminds us as the why the M50 lost it's reputation.
 
I finally got a chance to borrow these.
 
Let's discuss.
Build Quality:
- To one who can appreciate, is to one who's more likely to fall more in love.
Those are definitely words to live by when looking at this as a beginner headphone. 
It's a big headphone.
- She's built like a brick house.
Not to be confused with the song, but the headphone is heavily proportioned, and has a beautiful slick look, also durable... more durable than most.
 
Easily put, it's a headphone that for it's price, though not a Studio Monitor, it's built to take a beating like one.
 
Sound:
We aren't going to get into Highs, Mids, & Lows, but we'll discuss this sound signature widely.
 
My impression of the sound at first was that it had an artificial sound to it.
 
Be It This Is A Sub-Open Back Design by sound.
The Soundstage is a bit awkward though. I'd compare if to being in a square shaped room, and telling everyone to face their corner and begin to play.
 
This created a mere echo in the vocal signature, quite disturbing, but after some burn in the sound smoothed out, but remained to sound in that pitch.
The Bass is VERY FULL, TIGHT, & COLORFUL, it's full of character. I can't say that there's even a true sound for the Bass. 
 
That said, this headphone will kindly fit any genre, and is polite to Hip Hop, & Rap for a change.
I think after seeing that this didn't budge much with Rap based genres I found my disappointment.
Techno, House, & other Electric genres lacked clear detailing, they weren't as vibrant, and you didn't feel like you were getting to experience the vibrations and clicking that some people find in these genres.
 
 
On my last bit of information, I think with the things this can has to offer, it's the best in it's range if you aren't looking for a Studio Monitor.
It's unique, and I would also argue, if you're not used to Warm, or Cold Sounding signatures, and don't wanna jump into a random experience, this is perfect for the job.
I didn't find a genuine sound fit to this, it never had a too Bright sound, it wasn't ever truthfully relaxed, and the Bass notes, undertones, and playbacks weren't Warm sounding.
It's mixed, almost giving you a hollow type of sound.

I can only just about use these for an hour with Silicon Tips.

Tips...
- Silicon only last up to an hour, they make your ears scream in pain when you take them out.
- Foam Comply Tips, wash them well and they'll last you forever, keep them clean.

So, the IM50:
Why'd I buy them?
Well... I've not used Earphones since pushing on about 2010, and I really needed something good for just laying in bed on lazy days with, if I had more money it'd have been the SE215, but I think the IM50 are gonna make me just as happy.

So... Bed Headphoners,Earphoners.
Do some research, you'll see that warmth is there thing, warm sound, rich tonality, and why? It's relaxing, not everyone enjoys it, but yes... it's very calming.
Most Bedphone listeners don't really care for the Lemon Zest Bubble Tea+ Spring Guava, no. They like general Butter Coffee, or Cocoa, it's rich!

OK, Soundstage:
Feel free the make fun of my graph I made in Paint, but this is this only way I could describe the soundstage to myself.


The points discussed here were odd to me, a Soundstage that really left me wondering why the Earphones felt so congested at times.

Highs:
I actually heavily recommend a bit of tuning if you wanna bring out the Highs.
At first, the Bass, & sometimes overwhelming Lows swamped up the Highs.
But what's left to be said about them after an EQ?
M50 - Once properly fixed, the Highs are like the M50. Cut, copied, & pasted back into another device.
So what do I think?
Tune the M50 a slight bit, enhance it, you've got a percussion headphone, the same is left to be said here. A bit more masked, but sitting faintly in the back are the same Highs I knew awkwardly well.

Mids:
- Mids are flowing.
- Forward.
- Relaxed.
There's not much to say, the Lows are too thick to let the Mids shine with detail, but... with most Headphones/Earphones, Acoustics did OK for these.
They weren't super detailed, but they're definitely piercing, enough so that they can escape the lows at %30 Volume, & %50 Volume.

Lows:
Now for a already Warmer Sounding headphone, I expected this.
Lows were REALLY thick, the foam tips cut down on that some, but they could get congested very easily.
Unfortunately instruments were a bit difficult to find, but Bass detail was done very well.

Final Thoughts:
With everything said, people would surely assume that I've taken a strong disliking to these, which in false.
I think they're solid for the price point.

If you get the IM50, here are some recommended Albums, & Test Tracks(My Taste):
[album]Tara Terra - Daughter[Female Fronted Indie Pop/Soft Rock - ]
[album]Seth Corbin - Why Is Social Anxiety Ruining My Life And Why Am I Drinking So Much Beer[Folk Punk w/A Pop Side - ]
[track]Tiny Moving Parts - Clouds Above My Head[Emotive Punk w/A Taking Back Sunday Style Vibe]
[discography]Vulfpeck - Discography[Great for testing Monitor Value of these, Genre:Jazz Influenced/Funk/Sinatra/& etc... - https://vulf.bandcamp.com/]
[discography]Morning Effort - Discography[Great Lo-Fi Music for testing Highs, Genre:Emo/Bedroom Pop - http://morningeffort.bandcamp.com/]
[track]Hot Tears - Follow You[Indie Rock/Warm Music - Compliments the Genre Highlights these Earphones work better for - ]



Lastly, I ask that if you end up getting the IM50, be safe! And enjoy.



Last but not least, don't be immature about my Soundstage Description that I had trouble figuring out.
I needed to use it to explain the points of where I get lost sound, a missing point, or certain areas of the soundstage the separate and seem unnatural.
So, if you don't like how I tracked myself, or you think you're cool, and an internet gangster, don't comment, thanks!

Sony MDR-MA100
Quick Notes
"I feel these are an important staple in the world of "Lower End Headphones". They truly show that price means nothing."
Cons -
"Cans do feel cheap, and sound cheap when you jangle them around in your hands, you can tell they're built cheap."
Pros - 
"Despite suffering a jangling sound from twisting them left and right, and a few slams if dropped."
 
Sound Quality, & What You Get for $20
So, it's fair to assume that a lot of people outside Head-Fi would make the average comment in saying that "$20 is probably crappy quality." 
Thankfully we're Head-Fi, not the General Public!
 
When you get this package, the build of the case it comes in would lead you to think it's sound is poor, and they are just plain cans for a cheapo person.
Beyond looks, and mods, these are pretty interesting.
 
Bass
Some will point the finger and call these Bass Cannons, which is quite false.
They're pumping out a lot of juice to the bass, but I'd take and say that it's pushed more towards Mid, & Upper Bass ends.
 
Highs
I wanna argue that the Highs are colored, but in a manner of making them sound soft, and glistening.
They're pretty, not scarring, and won't tear your ears out.
Tinging isn't accurate, but it's hidden. With a glare effect that gives them an echo sounding shatter after Crash Cymbals, and Rides are hit.
 
Mids
Mids are pumping. 
I mean thrusting, or forward with Upper End Bass.
You get a slight bit of air pushed through the driver with EQ, though I don't recommend EQ'ing these.
But mids are accurate if you can push by the airy thrusts, and bumps, though I think it gives these a characteristic.
 
Lows
Low end is full of the Bass guitar solos, and lines.
It's not an all around important part of the headphone, but it's solid structure makes sure you know they're there.
Unfortunately there's no real detail.
 
My Mods
Turtle Beach Ear Force XL1 Pads to increase comfort, I personally didn't care for the velour on them, so I put them on my M50s'.


Size Cups, & Cans

So, I constantly hear of headphones being bragged about.
And as I always say, Headphones are like personalities, the most richest man could find the cheapest thing is best for him.
 
I've only Trial Tested these, I borrowed them from a buddy who works at a local guitar shop.
To say in the $150 range these are stellar is near close to an understatement. And frankly, they're definitely a Full Size I've finally heard the Bass done properly on.
 
So, Overview? 
At first, I'd no clue of Soundmagic, and their reputation. So, sure. I was very unsure.
But after seeing nearly every good comment on these, I forced myself to check them out after asking a buddy if he'd ever used headphones, or gotten into monitoring his guitar work, since he does play in a band.
I'd say I may a good mark.
 
Also, are you an M50 user who wants an upgrade finally? Here's your new cans, these are for sure M50 destroyers, and I now see why people say that this is perhaps one of the best upgrades you can delve into.
 
Soundstage:
This is pretty close to what I'd make an attempt at calling 3D Soundstage.
They aren't super accurate, and I'd argue that they are perhaps colored?
Guitars are separated well, and give you the venture feeling of almost touching the guitar as it's played. Weird, right?!
Drums can fade in, and pop out. Almost nearing what I felt could be a problem for some percussion geeks. They pop out of the sound.
 
Highs:
The cymbal sounds you get from these are great. Unique almost.
I'd argue that at some points these are headphones a Metalhead would love. They give a heavy, thunderous, crashy, slammy, & severe type of ting. Sometimes a bit ear piercing, but for the best.
Acoustic instruments sound good in these cans, but for some reason you get an immense bit of treble in the Highs, nothing that overrides the quality by anything.
 
One things, I see easy to explain is the guitars. And a defining reason I'd call them Metalhead cans.
Ever played Guitar Hero? Remember as you started a song up, you sorta heard that sound from the guitars as if they were being plugged into the amplifier? That's very revealing in these. The guitar play in these cans aren't held back, or relaxed by any means possible. They show so much appeal to these cans that it makes Electronic, Dubstep, Grime, or Rap hard to recommend in these.
 
Mids:
Bass guitars... Bass Guitars, Bass Guitars, Bass Bass Bass.
Literally the Bass guitar sounds in these headphones sound like they were torn straight from a pair of Beyers, sat properly, and given more Amplification.
 
Bass Guitars, NOT BASS as in BOOM BOOM BOOM, BOOM, BOOM, BOOM. 
That's nothing like these cans, they sound okay with Electric genres. But it isn't their forte.
But the bass in these doesn't really mash into the treble like Beyers do, and give you some funky colored bass.
 
Honestly, I think the Mids are the bass point in this headphone, being nowhere near muddy.
 
Lows:
I was honestly shocked, the lows contained everything with an Acoustic melody, but did an amazing job of keeping them hidden, yet able to hear, and still sounding amazing.
Acoustic guitars are one of the only Acoustic elements of their measure that really shine as an Acoustic instrument. They're over cumbering if you're looking for a headphone to jam out to Classical music with.
You just won't find it as pleasing, and I'd argue that you'd be better off with Open Back cans.
Better yet, wanna hear more? Violins were so pleasing, but almost a privilege to catch, yet when they were in queue, they sounded harmonic hidden in the background, very pleasing, and something you could almost learn to love. I think too many people focus too much on wanting to hear those instruments a lot, and it takes away focal value of a headphone.
 
My conclusion on the Lows? They're a treat you get with this headphone, a "hidden treat".
 
Conclusion:
These are amazing if you want a headphone that's fun sounding, but surprises you with a treat.
They are durable as anything, and a sight to see in person. I'd argue that the almost plain look to these makes you want to try them, and that the sound will take your breath away if you feel it enough.
I also recommend anyone who wants to get away from the M50, and find a new headphone to try these, they are stunning beyond all limits in what they do.

Takstar Pro80
This is a common reference headphone that has been made by several others.
But from what I've studied, and heard from others, the drivers inside are actually a Takstar Driver that isn't like it's clones.
 
If you're fond of the M50, MDR-7510, then read along.
 
This is not a detailed review, but will contain strong points.
Soundstage in these are ok, compared to it's Open Designed brother.
You receive a package containing the following.
- Tight Bass
- Bright Melting Highs
- M50 Style Bass Done Right
- Slight Beyerdynamic Style Brightness
 
This headphone WILL need Burn In to fully achieve the capacity of what it's designed for.
Also, critical listening is almost the same reference of the MDR-7510, being near pinpoint for a budget headphone.
Bass is something I had to grow used to when first listen came around, and it does pay off. People have numerously called these cans the M50 done right with few features. I can't say you're wrong!
 
I recommend this to anyone who wants to see what would happen when reference headphones meet, & have a child.
This. 
A sometimes Bright, Slightly Warm, Beautiful Mids, Crisp Highs that share the beauty of how precise tings should sound, and a headphone that truly helps you experience what true Burn In feels like.
 
Burn In:
Burn in should take up to 100h. What happens? The Headphones mellow out, they don't become a relaxed sound, but make it more a headphone you can use in Public Environments as a precision piece. The headphone becomes a DT880 Style sort of Bright, More Bass Depth is gained as well. 

JVC HA-S680
This isn't a detailed review.
 
If you are still an S500 user and prefer it's sound, get the S600, to see why, read below.
I'm still kinda shocked nobody has voided people from these.
 
Burn In Times & Changes
If you don't believe in Burn In, ignore this. But be aware you're missing out.
 
These cans can't be burned in by just listening sessions, Constant Burn In required.
10h Mark:
Bass will loosen a bit, headphone sounds more spacey.
12h Mark:
A little change, Mids were getting lost in the Lows, but the famous S500 Shiny Highs start to show their faces.
20h Mark:
Bass begins to hit a bit harder, and if you use low bit rate files, bass comes off muddy.
30h Mark:
Same differences, no real change.
50h Mark(Final Mark! These only need at least 50h)
-Highs became even more prominent, yo basically begin to get S500 style Highs that the S500 would get after Burn In times.
-Bass Response Tightens.
-Bass loses a bit of flooding Mids issue.
-Soundstage increases, Bass detail is more prominent.
 
 
So all that being said, there isn't a huge Burn In time, the headphone has more Soundstage and icreases rapid response and Bass Detail.
Bass isn't as mushy as S500, it's more tight. 
 
Mods:
Cotton Mod - Apply bits of cotton inside inner shell to reduce echoing in Bass punches.
EDT250 Pads - Bass loses rapid response, but increased comfort.

Incipio F38
Remember the famous budget cans, the RP-HTF600?
They we're great once modded, and so are these!
 
So let's talk.
 
This won't be a Super Detailed Review.
Overall Sound:
Highs are detailed, and YES this is colored, but not the same way that the HTF600 was.
If you remember, the HTF600 had a very shaded sound to the cymbals, detailed in violins, drums were kind melty, but who knows.
The F38 pays a ton of attention to drums, vocals are clear, and as I said about the M2X, they come off very playful.
Psychedelic music would definitely be the strong spot for this headphone.
I would argue that it focuses a lot more when you play Psych, as if the genre and this headphone were once friends.
It gets waxy, in a good way! Songs come playing through, and mellow synthesized spot sound natural, actually, more natural than any High End Headphone I've ever listened to.
 
Arguably, there are weak points here... Say to say. Lows are "cool" they just come off played out. 
Examples would be the Bass gets extremely tight, and cools down a flow, very fluid.
Maybe they were defined to sound this way, IF SO! Good characteristic, & IF NOT, why not put more effort into it?
 
Bass is SOLID, I wouldn't say Basshead Approved, but that Bass.
It's rapid, solid, detailed, and outlines itself from all the other points of sound.
 
Soundstage is OK.
Kinda reminiscent of it's non related brother, the HTF600.
Wide in the sense that it's almost too separated, keeping instruments in groups, separating them, then telling them so each go to one side of the headphone. 
 
I wanna argue that these are very kingly for a headphone in this budget range, and I'd recommend them to anyone who can tolerate a headphone that lets its aesthetics shine.
This headphone will show you what it has to offer.
 
I want people to buy it, try it, and review it here!
It's genuinely a solid headphone and deserves it's attention here, but I believe someone could review it better.
 
Mods:
Beyerdynamic EDT250V Pads Are A Must!
https://www.youtube.com/watch?v=Asxqk-rcnic
http://www.amazon.com/Beyerdynamic-EDT250V-Headphone-Pads-Black/dp/B0016MF7W2/ref=sr_1_1?s=electronics&ie=UTF8&qid=1427763055&sr=1-1&keywords=edt250+velour
You'll melt along with these headphones if you mod them. 

REMEMBER!
No elitists aloud here.
Headphones are objects with personality! The richest people can enjoy the cheapest headphone just because it provides the sound he's looking for, has the highs he likes, or just fits his personality.
 
Quick Personal Overview
-Detail is great for $20.
-Vocals come off as "cute", not serious.
-Clean Drums, not for people searching for genuine sound.
-Very Fun.
-Headphones detach in certain areas, but can be put back together. Besides that, be careful.
-Electronic Music comes out in detail, not the whole song, but certain beats with static will become easy to notice for experienced users.
 
AudioTechnica ATH-M2X
I've had these laying around for a while, and to say the least, what really drove me away was the chord. We're talking 10ft for a small pair of cans.
I finally have decided to pick them up, and I'm impressed, though they aren't a cheap version of HD800s' or something in that region.
The Important Thing: They literally remind me, and a few others of cheap Grado Labs Headphones!
I talk to a few others and a sound engineering place I visit down the street, and these cans have been passed around several times.
I've had three people say they're like a cheap Grado Labs Cans.
Although!
With that said, these aren't the most realistic sounding cans.
But read the review!
 
Description:
I usually wouldn't give a description, but enjoy this as it may help you image these properly without having to go off the deep end guessing.
The cans are extremely detailed. They sound like a nice pair of cans that don't overpower much at all, and make for some tasty sounding amp cans. I think I'd go as far as calling them Summer Cans, something with a sound signature that sounds good for the summer with their slightly Grungy Bass, Striding Straight Forward Sound.
 
Lows:
With these being open, and $20 you almost have to guess the sound before you buy them.
The Bass is very crisp, clean, and neat sounding, we're not gonna use the word pretty at all for these.
The Bass is Grungy, in the sense that Alice In Chains has a very straight forward, and hollow sounding Bass Guitar in %90 of their songs.
It's empty, but detailed. And I say empty in a good way, it's not overpowering, but leaves you with a bit of Treble, and not grasping for any more of the Bass. Personally, I find it's enough to make these cans what they are, it gives that Grungy personality to these. Not to mention, these were thought to be in mind for tracking guitar chords.
You can call them colored, and not on purpose, I feel that this was a purposeful design.
Be that in mind, the Bass is beautifully detailed.
Highs:
One thing I find important about these is their Highs.
It's their strongest point if you're chasing a slightly natural sound, or organic.
Cymbals are splashy in more Rock N' Roll songs, they dampen in Metal and give you that fast & dim detail.
Pop Cymbals sound sloshed together, and over emphasize the Mids too much.
 
Mids:
So here's where I noticed that this review would go sour for people, and it saddens me to know after I say this, a lot of you won't even give this a chance.
The vocals come off as cute, not candied, but just straight up cute, hearing the lisp off a woman's voice, and it sounding slightly studio produced, maybe a little bit candy coated with some sugar to make them sound sweet, & beautiful.
But it's not that big of a problem, to me at least. I listen to Indie Pop, so in a lot of cases it works out.
Male vocals are cute too, but they get rustled up in loud guitar points, and at times can seem like he's muttered out a bit by the guitar.
 
Conclusion:
I recommend anyone who's trying to delve into AudioTechnica and take baby steps to grab this first.
It's dirt cheap, and a great entry.
They sound OK with an amp, but you are aware that all it's doing is fixing up the Highs after a few songs.
Definitely a hidden treasure on the Low Budget side! I think if you don't have astounding expectations, you'll fall in love if the sound grows on you.
 
If you get the M2X, here are some recommended Albums, & Test Tracks(My Taste):
[track]Chvrches - By The Throat[Synthpop(Mellow song with plenty of highs, but demonstrates the headphone very well)]
[album]Bleachers - Strange Desire[Synthpop(Definitely makes the Sweet Vocals pop, and makes you wanna play on repeat)]
[album]PEARS - Go To Prison[Street Punk(pearstheband.bandcamp.com)
[track]Tomahawk - Mescal Rite 1[Experimental(Great track for tracking instruments)]

When looking at a headphone, you almost always forget that the more pretty, or whatever in may be that wins you over in this case, that headphone, it has a sibling.
This is the brother of a widely loved, and chosen as best for $200 bang for buck headphone, the Sennheiser HD598.
 
If we look around the headphone, there's really no difference when they sit side by side, maybe one has a bigger logo on the opening, and you also notice a huge contrast.
I'd argue that an idiot who looked at both of these would choose the 598 just because of its smooth color, and someone who didn't mind price would grab the 558, do research, and still appreciate his purchase.
The differences are fairly large in the grand scheme, but if you wanted gorgeous quality, and a fancy pair of cans you'd choose either of the two, let's be real. These two both look better than the Momentum. 
 
So...
Sennheiser HD558 vs. Sennheiser HD598
 
First up, Sennheiser HD598
So, in my original review I wasn't very considerate of these, and that's not the case fully.
The 598 is a lovely can for someone who can appreciate a wide open soundstage at $150-200, and they do it best in this range. I feel in this price range, when going for a can you wanna use often, you should often go for something more close, especially if it's your first pair of headphones.
My argument? Not everyone's ears are going to understand the point of an Open Ear/Back Headphone. But it's your money, you decide.
 
Mids:
The 598 is honorably a great listening piece, and warm like both cans in discussion. Though the emphasis is very different, the details to mids in the 598 is pretty forward, the mids are nearly close to fully bodied with detailed tones on most acoustic tracks. The mids aren't aggressive in most cases, but I heavily recommend an amp, and slight tuning. Working the mids around with the EQ without an amp can pump up the mids, and definitely begin to show highlights when you listen to the Slow Post-Rock/Trip Hop of Massive Attack, and Bowery Electric, or you can EQ them properly and pull some really gentle, crisp, and almost whisper sounding mids.
I really recommend giving them an EQ if you wanna use them for portable house listening and not have to worry about amping them. My ending statement, they're beautiful, warm, and can be tuned to come off clean and crisp.
Vocals don't come off too bright, they properly lay in the middle of everything without becoming overpowering.
 
Lows:
Let's discuss Lows with these.
Lows aren't a huge strong point for these by default. And it makes me wish we all used the same players, because I've got great tuning for these.
So these headphones aren't genre specific by any means, but! I don't recommend these if you're a Hip-Hophead who wants to blare his favorite bangers at top notch volumes, I'd promptly ask you to stop reading and look at the M50, SRH840, or MDR-7506, you're not gonna enjoy these cans as much.
So I said they aren't for Hip-Hop fans, correct! It's listenable, but I feel these headphones cater a lot to different genres.
Genres with more vocal coverage work awesomely with these! The headphone takes a lot of focus and buries it around a mellow, but warming bass, and not strong by any means, maybe a bit slim, but they are detail headphones.
Without an amp the Lows are great if you can find that tune, they'll pop a bit more without an amp, and may come off a bit more slim as I said, but it's what they do best! Jazz, Classical, Orchestral, & maybe even Blues come off with a detailed pace, heavy instrument focus, and no stress on any elements.
 
Highs:
Personally I feel the HD598 has a huge emphasis on the true acoustic measurement of a studio recorded songs tracking.
With all the elements in a song creeping up on you, you never really know what you're going t get out of a song with each full listen.
Cymbals are prominent, and very detailed, I'd arguably call them relaxed, which I think is good for beginners.
To myself, they don't have a whole ton of Splash, but you do get it in a Clean measure, definitely makes the Cymbals that come from the M50(my last headphone) swallow their tongue.
 
Conclusion:
Detailed beginner can, and relaxing, very clean, not too forward. I feel these provide something new with every listen, they are a bit of a unique character when it comes being a detailed pair of cans.
Warmth is very prominent in these at immediate listen, vocals are delicate, but very different from what AudioTechnica does with female vocals.
I hope that if you decide you want one of these, and you come to this site this really helps you get an idea.
 
If you get the HD598, here are some recommended Albums, & Test Tracks(My Taste):
[track]Angel Olsen - Windows[Jangle Pop]
[track]Wolf People - Morning Born[Woodsy Indie Rock]
[album]Tool - Lateralus[Progressive Rock]
[track]Alvvays - Adult Diversion[Indie Pop(Really Candied Fuzzy Pretty Indie Rock Based Pop)]
[album]Dan Wilson - Free Life[Pianist Rock/Singer for Semisonic]
[track]Best Coast - Our Deal[Beachy Rock/Female Vocalist(Best song I've listened to in the genre, brings out the patchy guitars notes, and truly makes the other Cymbal based instruments shine)]
[track]Miami Horror - Infinite Crayons[Synthpop Revival(One of those tracks where the beginning atmosphere shine right through, and you're greeted by warm male vocals with a soft background inhales)]
[album]Ty Segall - Melted[If you're into cruddy Lo-fi, this album is something that'll make this headphone sound "fun"]
[track]The Moldy Peaches - On Top[Anti-Folk(An Anti-Folk track with a cute soundstage. Just listen, make fun of me later)]
[album]Neutral Milk Hotel - In The Aeroplane Over The Sea[It's a Cult Followed Indie Classic not everyone will enjoy, but I thought I'd throw it in for good measure, (listen if you're an acoustic fan)]
[track]Amy Grant - I Will Remember You[Random find, great for beat tracking, in my opinion]
 
So, we've discussed the 598
 
REMEMBER!
Before we jump in, I don't feel as if a certain headphone is better than another! Not with any headphones. 
I see headphones as a thing with a personality, and each does something different, which makes us choose an older headphone over a newer one, or other way around.
 
The Sennheiser 558
The 558 does have a role that you're not going to catch on the 598, again. All headphones are different, they're basically a personality. 
For the price, you get the same sized package. 
My argument here is actually pretty different. If you want a headphone similar to the HD598 at a cheaper price, get the HD558. I also feel it's safer getting into these first!
If you came from the M50, and were to ask me for something Open Ear/Backed for $100 or a bit more, I'd recommend these in a heartbeat.
Why I'd Heavily Recommend To An M50 User
These cans are my style, the HD598 belong to my brother anyway.
Dark, Smooth, and sound Luxurious to any who prefers a thicker sound.
They're quite a bit Bass influenced in my opinion, not HUGE BASS, but bass that shines brighter than what the HD598 provides.
An M50 user could get used to these with a proper EQ, and perhaps fall in love if he/she were open to Open Ear/Back Cans.
HD598 & HD558 True Difference
They're both gonna provide a warm sound, but hand in hand, if you want a Mid focused headphone, the HD598.
The 558 carries a good portion of that detail, but lays the warm blanket over it's head with a smooth, thick, warm bass. It lacks in depth at some points, but sill fares to it's own.
Mids:
The 558 is extremely unique!
The mids will almost seem squished to you, they feel really shut into the background, which isn't bad at all for a darker sounding pair of cans, it's almost pleasing if you bought these for relaxing.
You get a bass that's fit in really well, tight at points, but doesn't choke out cymbal points. And on acoustic songs with a bit more Synthesizer in it, it's a sexual feeling almost... To the point to where these cans can be so warm, with closed eyes I felt as if vocalists were pressed against my chest and singing in my ear. 
I want to warn people about using an EQ an messing up the bass too much, the bass is nice and rich like dark chocolate where it is stock, but if you over-tune the bass signatures, you can accidentally close out vocals on tracks at times, and the headphone loses its origin.
Vocals are an important part of the discussion. While they are formed kindly into the background, they are piercing, and fierce! I almost get a Grado Labs styled vocal presentation.
Male vocals that are more light will show better, and vocals in general shine on both at nearly the same frequency.
 
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=2861&graphID[]=2851&scale=30
 
Don't take this to the extreme, but do you research! Sound is subjective. If it's good, you've owned/own them both, and you have different listening situations for them both, then that's your taste, there probably isn't anyone out there with your desires. 
Your EQ is subjective to your sound preference.
 
Lows:
The treble might come off as a rumbling form of treble. I found this to be a strikingly good thing!
I enjoy that feeling of a 450,000lbs rock tumbling down a cliff, and you hear every pleasuring detail. I'd argue that the bass is more pleasing, yet remember, this is a dark headphone.
Bass is an Open Ear/Back generally brings in that warmth.
So, as I described the mids, they feel pressured onto you, and if you love warm, smooth bass, this is up your alley.
The headphone excels in the lows, but I feel they do their job of comforting your ears all round. This is definitely a headphone for getting home, and just laying down, or prancing around the house with these on.
My last bit on the lows, they're literally dark, no question.
I don't recommend these to anyone who wants a nice bass, but less warm feeling, I'd shoot you to the HD598.
 
Highs:
The highs are not much like the HD598, they've got some traits, but the Cymbals in tracks pierce more, the drum set stays like it should, balanced. But detailed.
I'd argue that the HD598 has more detail in the highs, and the HD558 keeps them placed in with the lows in the mids. Sure, you're definitely going to notice the highs with the HD558, but they attack you almost again like a Grado Labs Headphone. I really can't sign off a lot on these as there a bit more different.
 
Conclusion:
These are something everyone might be able to appreciate.
They're a 24/7 Headphone for me since I can't/don't need $400-700 cans.
There's really something special about these, and the reason I say that is quite simple. They aren't much like their younger brother the HD555, those are for a different sort of person.
But when I say special, I feel these definitely do their job better than a lot of headphones in their price range. 
 
If you get the HD558, here are some recommended Albums, & Test Tracks(My Taste):
[track]Pure Bathing Culture - Pendulum[(http://purebathingculture.bandcamp.com)Synthpop/Dream Pop]
[album]Mac Demarco - Salad Days[Indie Rock, Pretty Patient(An album I feel the HD558 used to focus more on the separation, and it gets warm as well)]
[track]Dent May - Born Too Late[Indie Pop/Synthpop(A summery album, but the vocals on this song shine through as warm, and relaxed)]
[track]Tamaryn - Mild Confusion[Shoegaze(You'll understand! Shoegaze is amazing for these cans!)]
[album]On An On - Give In[Shoegaze/Synthpop]
[track]Factory Floor - Fall Back[Electronic Post-Punk(Bass Heavy, crazy track)]
 
 
Final Thoughts
I've not had the cracking experience, and from what I'm aware of, it's only common in people who aren't careful, I'm not sure though.
 
I personally use these both, I prefer one over the other, then again, the one I'm craziest over is mine!
I hope this was somewhat helpful to you.
 
 
 
My reviews are more of tales, but with a nice quantity of headphone experience, but I like including the other things that really tell you more about my experience. It helps you picture them in your life if they were on your list, and gives you things to consider.

So, if you've read anything by me, good!
I've used many cans.
But I'll never spend over $250 on a pair of headphones.
I don't feel it's necessary. 
 
REMEMBER! Headphones Objects With Their Own Personality
 
On that note, let's talk Sennheiser HD598s'!
 
Quick Personal Overview
When talking Sennheiser, it's definitely easy to say that Open Ear/Back is their profession.
I've never cared for any of their Closed Back design cans.
The HD598 has a personality all of its own, and definitely a unique Detail Headphone.
Before I begin the review, read below.
Never compare a headphone to something that's completely different.
Sennheiser HD598 - Detail Can, Not Meant For Heavy Bass! But If Amped, Bass Becomes More Detailed, Not Very Warm Though It's A Warm Nature Can, Similar To It's Brother The HD558.
HiFiMan HE-300 - Soundstage Can, More Bass, But A Strongly Emphasized Soundstage Headphone.
Don't compare these two just because they come close in price.
 
Sennheiser HD598
 
First off, we're gonna discuss different things from my HD558-HD598 Double Review.
 
This can has an important role for me.
When searching for headphones, you should go for whatever is closest to your preference.
These cans are definitely a Highs, & Mids based cans.
 
Highs:
These Headphones don't pack too much bass at all.
Cymbals are definitely an important part of this headphone, they pierce though. So if you're a percussion guy, I do recommend against.
Unless you genuinely want a headphone that has interesting pierce through bass splash.
I'm going to argue that in the $200, this is the cleanest you can find, and if you decide to buy an amp for these cans, work out an EQ.
Cymbals are gracious, but could definitely sound a bit more realistic for some people. I'd argue they are definitely a bit more colored than explained by others.
Another important thing about the highs is that they are heavily focused on acoustic instrumentation. 
Arguably, the acoustic instrumentation is some of the best you'll find on a $200 & Under range headphone. I will add! If you want a headphone that you plan of using strictly for music that carries an acoustic emphasis, search around! There are headphones meant for this.
 
Mids:
The emphasis on the mids for this headphone are usually quoted as being very forward, and I think this is wrong. 
With this headphone being quite warm, these cans give a very full bodied mid level, for it's standard, it's one of the best for people who like "sharp vocals". 
Details in vocals from females are great, but nothing like AudioTechnica styled female emphasis, but I'd definitely know you in the way of the HD558 if you want a thick female vocal range.
I really recommend giving them an EQ if you wanna use them for portable house listening and not have to worry about amping them. My ending statement, they're beautiful, warm, and can be tuned to come off clean and crisp.
Vocals don't come off too bright, they properly lay in the middle of everything without becoming overpowering, but again, they can be piercing.
 
Lows:
Let's discuss Lows with these.
Lows aren't a huge strong point for these by default. And it makes me wish we all used the same players, because I've got great tuning for these.
So these headphones aren't genre specific by any means, but! I don't recommend these if you're a Hip-Hophead who wants to blare his favorite bangers at top notch volumes, I'd promptly ask you to stop reading and look at the M50, SRH840, or MDR-7506, you're not gonna enjoy these cans as much.
R&B is a smooth genre with these, since a lot of vocals in R&B can be high pitched, but even with that said, they get lost in the highs.
Vocal Coverage is a big focus on these though.
I won't slam it again with "vocals are lost too easily", though they can in some genres. High pitch vocals, Height in singing, or distant vocals are a true standpoint for these.
Guitars work well, but I will argue that you miss the vibration of the brush of strings, you just end up the echo. 
Examples for this are simple. Listen to a few guitar tracks, you'll find that you don't get the slight vibration that some cans give off after a stroke of an acoustic/electric guitar, but you get the stiffening of the strings.
Lead guitar chords can overlap songs, this was a sacrifice I had to learn to make with the HD598 over the HD558.
 
Conclusion:
I recommend this to someone who's chasing detail.
Maybe grab the HD558 if you want more bass, and that dark sound.
They are a warmer can, so if you really want these, make sure to think about what you're getting into.
 
 
If you get the HD598, here are some recommended Albums, & Test Tracks(My Taste):
Remember, I've got my own taste, you can't judge if you don't know me.
 
[track]Rob Crow - Sophistructure[Indie Rock(Provides a good example for the Vocals as I explained)]
[track]Chvrches - The Mother We Share[Synthpop(Not R&B, but this is an example for what I meant)]
[album]The Men - Open Your Heart[Misc. Rock(This album has some good acoustic instrument points. Can be detailed for experienced listeners)]
[album]Treepeople - Just Kidding[Proto Grunge(Album is good for the Highs, and Cymbals I exaggerated)]
[album]Tyrannosaurus Dead - Flying Ant Day[Grungy Indie Rock/Lo-Fi]

Level: Amateur Mostly
Experience: First Personal Pair
 
We can all agree it's been reviewed too much?
Good.
My turn please...
I'm aware of the reputation these carry, how audio should sound to a newbie, and the relative price point for most people is fairly affordable.
But after having such a long rep, and being the most top recommended headphone out there, I see where some things are wrong in my book, and that I, obviously as every other soon-to-be/experienced audiophile have different preferences per sound.
They lack to me, but I see where a newbie could melt over these if it were their first on ear.
Female Vocals are a shiny whistle, the bass isn't too much, but enough to give a good bite if you want something with better sound quality than a pair of Beats, which makes these a sensible choice.
Love shiny guitars? Lossless albums really cater to these, if it's a Rock subgenre, or something of the same nature.
Vocals aren't too candy coated, sound doesn't leak, acoustics sound fine, vocals can be breathy on tracks.
 
With all this positive said, what's my issue?
I can argue that my issue was mistakable in buying these, but then I'm looking back on my year of 20.
I had no audio experience, I'd seen these headphones given high ratings, and I'd always been searching to get the best for my habits, and some suitable to my listening habits. Come on, we aren't all rich.
So, here's my small input on issue, don't let these silly opinions void your purchase.
I feel as if these are chaser headphones. They're great, but the mids lack, I feel as if I'm trying to find more value by changing my preference in kbps.(256 kbps, VBR v2, or FLAC is what I prefer)
Another issue that kinda killed me off after my Six Month Period with these was more personal. I don't just listen for quality, I generally revisit a bunch of albums over and over, and when I do, I get caught in long listening hours. So why am I whining? The M50s' are strenuous, I could/can only get through a max of 3 listening hours before my head has enough. 
With all said, they're my only present set I have, if I had a job, I'd probably have more headphones.
 
 
So, with all of my personal complaints out, what's my verdict?
#1. They're Monitors for sure, keep in mind, a Monitor Headset to you isn't always going to be a monitor set to somebody else.
#2. If you personally enjoy the feedback given on them, BUY THEM, only as a beginner headphone.
#3. If you're new, headphones you buy for serious listening need to be something that'll last you a while, especially if it's your first set.
 
My feedback is this, they're gonna please someone who generally wants to get into serious listening habits, unmasking hidden instruments in songs, and hearing backgrounds.
Someone who's coming from a headphone a bit lower scale? I came from the ATH-WS55, they're a moderate upgrade, but before you commit to the purchase, go out and listen to different headphones, frequent them, see if they are gonna be what you truthfully want.
 
Last words, these headphones have somewhat of a "Cult Following", and they're recommended to anyone who wants to take their listening seriously.
I feel this needs to stop, we need a chart, a chart of headphones around $200 range to show people options, not force them into something they may have not completely read up on.