

That said, let get into the real topic.

• Earphone drivers: 9mm neodymium
• Frequency response: 12Hz-22KHz
• Sensitivity (1KHz, 0.1V): >100dB
• Maximum SPL output: >120dB
• Impedance: 17ohm (estimated)
Included:
• 4 sizes of proprietary eartips (S, M, L, XL)
• 2.5mm stereo plug adapter
• Airline dual-plug adapter
• 2-ft extension cable
• Shirt clip
• Carrying case
• User guide
• 2 year warranty


The packaging on iM-590 is a genuine improvement over the old iM-390 blister pack. Nothing is sealed hard so there is no need to cut around. Definitely one of the best packaged sub$100 IEM in the market. Needless to say, you will find pretty much all the goodies in front of your eyes as soon as you opened the front cover. The only thing missing is the extra large eartips which hide inside the hard case. AsI had commented before (on iM-390's review), the included case is one of the best quality hard case included with any IEM.






Sound Quality
I burnt iM-590 in for 50 hrs but didn't really notice any significant change in sound quality. Like iM-390, the impedance is not listed on the official spec but I did a quick measurement and it turns out to be about 17ohm, which means iM-590 is quite easy-to-drive and no need for amping. Isolation is by far the biggest weakness of iM-590. The fused tips themselves are not quite as isolating as normal single flange which means isolation is slightly worst than single flange shallow inserted IEM like the CX300 or EP-630 [See note 1]. There is also a bit of wind noise in windy condition since there is a vent underneath the earpiece, but not bad enough to consider as a turn down. Though still decent for daily use, you might need to invest in a pair of Sony hybrid eartips (EPEX10A) for noisy environment, granted that it will never be anywhere close to as isolated as a pair of Etymotic.
iM-590 is on the analytical side but still quite balanced overall. Bass is not particularly strong and a bit roll off at the most bottom end (40Hz and below) but it has good attack, control and presence overall. Upper mid / lower treble is a bit more forward, Etymotic-like but not as piercing. Pretty good on vocal most of the time but there is a tiny bit of harshness on brighter recording. Treble is well presented and quite detail but not the best I have heard. Soundstage is above average, airy and specious especially in term of depth. In sum, iM590 is a well balanced, detail sounding IEM.


Though not the best sub$100 IEM I have heard, iM-590's overall sound quality is well above its asking price of US$60. Coupled with the fact that it comes with a wide range of accessories and a good 2 yrs warranty, it is hard to not consider iM590 as one of the best sub$100 IEM package around.
You can read the quick sum up here.
Note 1: You can try this simple mod to improve the stock eartips isolation. Click for larger picture.