Sennheiser CX 300 II-Black

Sennheiser sound signature at its best.

firstly, i think, these earbuds have 9mm driver instead of a 13.5 mm one, which may be a reason for smaller soundstage. for the price, i expected a better soundstage, ex300s cost less, yet have better soundstage. The bass is good, goes low. highs and mids sound good too. SOME PEOPLE SAY THESE ARE MUDDY AND BOOMY, BUT THESE AREN'T CX300, THESE ARE CX300-II PRECISION. The sound is balanced, with nice bass. Not much detail though. but, a balance and clear music experience. Highs are sweet. burn-in helps these to become more balanced (could be an illusion). 
 
The build quality is fantastic. The size is small, fits well, perfect isolation, comfortable. The cable isn't flat, but not very hard to untangle. They lasted about an year with me, but i am not good at taking care, i bitten on the wire while listening, i caused a lot of damage to them. at last, the left side stopped working, whereas the right side sound was as good as new.  
 
they could get 5 stars if larger drivers were used, like sony does. larger drivers make noticable difference in sound.

    I am not the best at reviewing.. but here I go.  I bought these headphones just to use on the go and was very impressed by the price performance. I own the flagship Sony H3, and they very similar in the SQ department. It is not bass heavy at all. Any iem with good bass would essentially be an improvement on these. It is not a headphone that with wow factor. It is just great for casual usage. 
 
Design:  It is designed to have the right wire wrap around the back of your neck to help fight microphonics. However, it bugs me a lot. If you don't put it behind your neck, it hangs on the left ear and swings back and forth as you walk. It is a little silly in my opinion. It does stay in as it swings though. I use it for working out. It isn't the best headphone for staying in your ear as you run. I have to wrap it around my ear in order to keep it in as I jog. It gets moist easily and starts too fall out.  
 
Otherwise, it is a great little headphone for on the go usage. Good enough sound quality, and if it breaks, it only cost you 36 bucks to replace. Quite a good deal in my opinion. If you don't feel like putting on full sized headphones, these have good enough quality for any casual usage. It can be a tad boring if you are expecting it to be like a full sized headphone. It is definitely better than your cheap in ear headphones that come with your phone though!

I bought these looking for a replacement to an older pair of in-ear's, and happened to stumble upon these.
At first, I was very pleased with the sound, as it was a drastic difference compared to my older pair. Only now i realized that these are IEM's after visiting this sight. It was only after i bought my AKG 240's I truly noticed the sound quality.
 
The sound quality you ask? Well they are very nice overall, as expected from Sennheiser. The only big flaw is the amount of bass seems to drown out all other sounds. The high's seem to disappear every time the bass kick's in which is obviously a great draw back.
 
Otherwise these are very comfortable and fit nicely into your ear and stay there like they should. The isolation is superb, and coming from a person who takes a clankity bus every day to school, that means something. No leakage either.
 
I would recommend this to Bass-heads, or people who mainly listen to Rap, Hip hop, or love bass solos.

[size=medium]I had an old pair of Sony over ear IEMs which needed to be replaced for use at the gym. That is when I thought that I would try the Sennhieser CX-300 II. I have a pair of HD-448 full circumaural full size headphones which are really nice and I had read a lot of good things about their equipment.  So, I decided to buy them at Best Buy for $50 knowing that Best Buy has a really good return policy if I didn’t like them.[/size]
 
[size=medium]I opened the package in the parking lot to be sure that there weren’t any problems. First of all the packaging is difficult to open. The plastic pinches the wire just below the strain relief next to the speaker unit. After getting them out of the package I was pleased to hear that right out of the packaging they sounded better than the old Sony or the Ink’d IEMs. [/size]
 
[size=medium]This comparison isn’t that complimentary considering that the two the Senn’s are being compared too are sub $20 units. They have a much stronger bass and fuller sound in all areas. The Ink’d are great for the gym but  in a quiet environment their sound signature is full of holes. They have a lump in their bass around 200 Hz that drops out between 500 Hz and returns just after 1 kHz.  The Senns on the other hand are a bit boomy in the lower bass from 20 to 200 Hz but transition well into the midrange. The highs are bright and do not suffer from the bass as others have said, But I must say that I HATE sibilance and a warmer sound is much preferred to a bright sound at the expense of too much sibilance. [/size]
 
[size=medium]The dreaded  J-Wire…[/size]
 
[size=medium]Now some people like the J-Wire  and some prefer the Y – Wire configuration. The 1/8 plug is 90 degrees, but sticks out rather far and doesn’t have a strain relief which is a poor design. The junction point is dominated with a ¾ by ½  chunk of plastic where the larger diameter wire meets the two branching wires going to the individual speakers. If worn casually the light weight wires are comfortable and I don’t notice them, but when working out the long J-wire tends to fly about and get caught and pull on the speaker for the right side. This configuration also prevents me from getting comfortable over-ear configuration.[/size]
[size=medium]After buying these I decided that I had to get a pair of IEMs that contained a microphone and controls for my iPod. I researched and considered getting the CX 400 or MM50 but both have the J-Wire configuration. [/size]
 
[size=medium]Take a Note Sennhieser… Offer your products in both configurations! It really can’t be all that difficult to produce a CX 300 IIJ and CX 300 IIY. [/size]

After getting mx 170 of sennheiser whose sound details were amazing . I was much expecting from these earphones . The so called cx 300 ii was not even close in detaling of sounds like mx 170 . And all my sennheiser earphones had issues after 8 to 10 months . So better get them in warranty of 2 years . Overall its a very good company . I am getting new earphones this week . Can anyone suggest to get cx 180 or mx 170 . I need detailing in sound .

Best Part Of these Headphones are the Bass.....  And Worst Part Of them is Bass.... Yess...... Audio lack quality... In fact no detail at all.. mids and highs are not present.... various instrument goes unheard... 
 
Don't go for these earphones if audio quality is your concern.... These are just suited for thumpy music found in electronic and hip hop.... that to below expectation....
 

Bloated and muddy bass with a veiled midrange and a lackluster treble. 
 
These are horribly overpriced in Australia and can be found at an authorized dealer from $60-$100, although I bought mine way back in the middle of 2009. What can I say, there are so many things out there for the price that whoop these thing sonically that there is absolutely no reason to own this. The amount of counterfeits floating around astronomical. I must say they are quite durable though.
 
These were my first step into the world of audiophillia.

I purchased these from Best Buy, having read good things about Sennheiser during my search for a cheap pair of IEMs for the gym. I ended up exchanging them for the CX400-IIs because I was disappointed with the 300s. They did not perform like a base model should.
 
I was displeased with the lack of clarity and separation. And I realize the for under $100, I cannot expect too much, especially from a single driver. However, these were not much more pleasing than my Sony IEMs that I got from Target for $30.00. Spring for the extra $20 and get the CX400-IIs. The difference in clarity and separation is immense between the two similar models. Also, the soundstage on the 400s is broader, and the sound is more dynamic. The 300s sound flat.
 
On the plus side, the size of the 300s and 400s are the same, and they fit wonderfully in my ears. They are very discreet and comfortable. Not clunky or awkward at all.