Yes, I agree that the bass on the IM50 is well done, and integrates well with the rest of the frequencies, but that does not mean it is neutral.
I do understand where you're coming from when you describe one earphone as brighter/darker than another, but again, this is simply a relative comparison. And yes, I do know that we can become used to sound signatures, particularly if we are A/B-ing between earphones with very different ones.
I guess I will have to respectfully disagree with you that the IM50 and 70 are neutral. In fact, I would contend that the IM01 is also not neutral, but is quite warm sounding, relative to earphones that are generally agreed upon to have more neutral sound signatures, such as DT880, JH13, and UM1. In no case would this make the new ATH line poor value--they are very good value, except perhaps the 01, since it is very close in price to other single BA monitors (e.g. UM1). It's certainly a good time to be into earphones.
We do hear and perceive sound signature differently, so differences are common. All reviews should be taken with some grain of salt
Just to clarify on the definition of natural sound. Natural sound to me is more toward the realistic type of sound. Sound signature that is closer to what I hear from a real live concert. Not only on the tonal balance, but I rather sensitive to the dynamic. The contrast of low and high spl, also how realistic the dynamic I could hear / feel from an earphones / headphones. Many analytical sounding earphones that has good flat tonal balance often fail to impress me due to the lack of their dynamic.
I sing in my church choir, and we often held concerts with orchestra. I use to stand rather close to the double bass or sometime tympani, also pretty close to the wind instruments. The dynamic of the sound I experience from those acoustic instruments was so great and intense, full and immersive, something that I often miss from earphones. Yes the dynamic would be much different from the audience place, especially the back seats. So from the perspective of realistic dynamic, IM50 & IM70 do have a very good dynamic that is closer to the natural dynamic, than many other natural sounding earphones. The dual symphonic drivers really do their job well, making symphonies sound realistic
Tonal balance wise, yes, as mentioned, they have emphasize more on bass, more towards natural-dark sound signature. I think it is fair to give natural-dark signature to be on the same level as natural-bright signature in perspective to the natural sound signature.
With Fiio X3, they sound more bassy, therefore less natural, than when I played them through DACport. DACport somehow makes their tonal balance more natural, less bassy.
Well just put it this way. I played many classical albums using my IM50, although they have some emphasize on bass and lacking some air, but all the acoustic instruments, be it strings, winds, percussive instruments, they all sound natural to me, no strange frequency artifact. It only lacking some air, but the acoustic instruments all sound natural enough. In comparison, I also have other natural-dark IEM, Yamaha EPH-100, that I can only enjoy with modern genres recorded with closed miking techniques, not with classical albums. Well, these days classical recording also use a lot of spot mics, not like the olden days where they mostly rely only on stereo mics. With the older classical recordings, yes the lacking of air in IM50 does make it less enjoyable. But I enjoy them more with newer classical recordings, that sounds clearer than the older ones. YMMV
I'm presently using Yamaha EPH-100 with RSA Shadow and an iPod. I had the FXD80 and returned them. I had the Shure SE215 and found them too congested and muddled. Pairing with the RSA Shadow listening to everything but country, with a healthy dose of pop, chillstep and EDM, which is best?
Unfortunately I don't have RSA Shadow to test them. Looking at their spec of 250 mA per channel, most probably it has low Out Z, so IM02 to IM04 would be alright. But please note, if Out Z is too low, IM03 treble might started to sounds harsh.
But if you like EPH-100 sound signature, I suggest you try IM50 & IM70, as they are closer to EPH-100 sound signature. And for my preference, IM50 & IM70 are better than EPH-100.
FYI, I enjoy both EPH-100 and JVC FXD80, but for different type of recordings.
Thanks for the awesome review! But when I tried the IM03 and IM04 series I heard a very distinct peak around may be 7 to 8Khz, making them sound very sibilant. No one else seems to hear it. Now I am beginning to wonder whether I was missing something. I used the X3 as a source by the way.
Yes IM02 is the best value and infact I liked it way more than the rest of the IM series. Fantastic IEMs.
Yes, with some low Out Z amps, it may produces treble peaks. But what I don't understand, not all low Out Z amps causing harsh treble. For example the Hifiman HM-901 with the Minibox amp module, although it does sound brighter than DACport for IM03, but in a nice way. Try IM03 with DACport (10 ohms), they pair really well
Unfortunately for those using AK100 (20 ohms), they won't agree that IM02 is the best value for them
IM02 on high impedance sources sounds rather metallic on the treble. But with low Out Z sources, it sounds wonderful!