Sound
In their respective product details in AliExpress, the dynamic driver of the C10 is stated as a “10mm double magnetic circuit dynamic unit” which is a “low distortion professional dynamic unit” with “magnet volume increased by 30%” while that of the ZSN is a “10mm self-developed titanium film dynamic unit” that brings “stronger driving force with a four-layer voice coil”. This may be true and the two dynamic drivers may in fact be different, or they may after all be identical, because the C10 and ZSN bass do share similar characteristics.
C10 bass is tight, punchy, as fast and as controlled and reaches as deep into the sub-bass as that of the ZSN. Perhaps even deeper. It also seems to have more mid-bass prominence which imbues a warmer foundation to the C10’s sonic signature. The transition from upper bass into the lower mid-range is more restrained; I encountered masking of mid-range details only in the most complex songs. Because of this I could say that the C10 resolves low frequency textures and details a bit more. In my swinging and bebop Jazz reference tracks where the double bass and the drums exclusively set the underpinnings of the rhythm, I could, in the C10, just begin to discern the delineation between the percussive impact of the kick drum and the snap of the bass strings when plucked, as well as the trailing edges of these transients, from the faster decay of the drum to the slower and lingering reverberation of the double bass. In the ZSN I could not; these details seem to be there yet not there, inchoate, blending together in the field of sound being reproduced. I can only imagine what it would be like to listen to a pair of TOTL IEMs with all such gradations of textures and dynamic progressions of transients presented with all accuracy, precision and clarity. Still I cannot help but marvel at the resemblance between the two in-ears in the way they reproduce bass.
Like the ZSN, the C10 does not sound as recessed in the mid-range relative to the rest of the frequency spectrum but, unlike with the ZSN, the sensation of proximity is not as pronounced. Voices, both male and female, aside from having more body are not presented as upfront (or more precisely, in-your-ears) as in the ZSN. This sets up a broader sense of perspective where the voice is not disembodied as it sometimes is with the ZSN in close-mike vocal recordings; but is perceived as a resultant of movement of air from the chest, through the larynx and throat, shaped by, and out the mouth and nostrils. Female voices are especially intoxicating in the C10, such that I'm totally engaged in the absolute mastery of restraint and vocal control of Sarah Vaughan and Barbra Streisand, the perfect pitch and effortless technique of Ella Fitzgerald, the raw emotion evoked by Billie Holiday's phrasing and tempo.
Instruments too seem more natural with the C10; drums, cymbals and their iterations, strings, winds and the piano just sound more lifelike. Or perhaps it's because the warm foundation of the bass imparts fullness, a sense of solidity, which I very much like and prefer.
I also hear in the C10 the rudiments of that ability to resolve more subtle details across the audible frequency range that I fully enjoy with the HiFiMAN HE-400i and that I have never as completely heard from any of my other earphones, with the exception of my venerable detail champ, the Ostry KC06A: finger plucks on strings, fingers sliding and pressing on the finger board, ringing squeaks of finger pads on strings during that vibrato, the thumps of fingers on trumpet pistons and other such mechanical interaction with instruments; taxed breathing by cellists; sharply drawn huffs and more gentle puffs of air, those wet smacks as singers’ lips open and close. Again I imagine what it must be like to listen to such with IEMs that are the absolute best in detail and resolution. But to hear them, even on a basic level, from a $26 IEM ordered online for COD is truly liberating.
The C10 has no problem with vocal sibilance (S, T and Z and other fricative and affricate consonants generally heard from 4-5 KHz and sometimes to 8 or even 10 KHz). It must be noted that sibilance per se is part, and a natural function, of human speech. Every day we express, and hear, sibilant speech. Think “She sells seashells by the seashore.” It is only when vocal sibilance inherent in a recording is improperly or unnaturally reproduced as when there is harshness or stridency even at low to moderate volumes that it becomes irritating and undesirable.
Spanish Harlem sung by Rebecca Pidgeon from her album The Raven (Chesky, 1994) and the first song track in Chesky's Ultimate Demonstration Disc is an example of a naturally sibilant recording, what with all those sibilant consonants in the lyrics. The vocal sibilance is there, but it is integral to a song that's oftentimes used as a benchmark for high resolution audio. Attenuating or smoothing this will result in a corresponding loss of detail—for one, the distinctive variations in the sound of the shaker won’t be there anymore. If the headphone or speaker has a spike in the frequency range concerned, then Spanish Harlem would be intolerable. Therefore the reproduction of Rebecca Pidgeon’s voice has to be just right.
Another test for sibilance, a comprehensive one at that, is Linda Ronstadt’s trilogy of traditional American standards, also known as the “Round Midnight” trilogy: What’s New, Lush Life and For Sentimental Reasons. Ronstadt’s manner of singing and the way she articulates and aspirates her words in the languid style of these recordings naturally emphasize the sibilant consonants.
I’m very glad to say that the C10 aces both of the above.
Treble detail and clarity is likewise better expressed in the C10. Continuing with what seems to be its main character of restraint and control, it also exhibits that crispness and sparkle found in the ZSN but with a finer yet smoother silhouette. At first I perceived the upper brilliance region as somewhat subdued, with a limited sense of air up top, in direct comparison with the ZSN which seems to extend more. Later on I realized I mistook the ZSN’s intrinsic brightness as superior extension and airiness. Indeed, listening to Lush Life from Maynard Ferguson’s high-energy Live From San Francisco album (Omnivore, 1994) showed this. Ferguson’s acclaimed ability to play the trumpet in extremely high registers with full tone and power yet preserving musicality is showcased in this John Coltrane jazz standard. The C10 handled all of the soaring trumpet notes against the backdrop of the shimmering cymbals and the other horns with composed dexterity while with the ZSN I always have to turn down the volume a bit in certain passages because they are borderline strident. It seems the C10 presents detail with a restrained, smooth, glare-free transparency, if one could visualize the metaphors I’m using. I actually prefer this smoothness of treble character, conducive as it is to longer fatigue-free listening sessions.
Imaging, the positional and spatial cues in the sound field (e.g., where the musicians are situated, their distance relative to each other, and to the walls of the room in a live chamber music recording), is excellent in the C10. Going through the entire Ultimate Demonstration Disc and the Ultimate Headphone Demonstration Disc (both from Chesky Records) confirms this. The album Live From Studio A in New York City (Chesky, 1994) featuring Johnny Frigo with Bucky & John Pizzarelli, Ron Carter, Michael Moore and Butch Miles is a stellar model and audiophile standard for imaging (See Reference Notes). I appreciate listening to this with the HiFiMAN HE-400i, the imaging of which is for me perfect. The C10 out of all my earphones comes closest to that aural experience.
Soundstage, which determines the shape and size of the sound field that contains all those imaging cues, and that is created by the headphone itself, is very wide, with sufficient depth in the C10. The left and right expanse and receding extent of the horizontal sound field are easily perceived; height, however, takes focus to place. Admittedly all these are still taking place within the confines of my head, with the center image of sound still plastered to the upper middle of my forehead. The aforementioned Live From Studio A and binaural recordings such as Ottmar Liebert's Up Close (Spiral Subwave, 2008) and Stripped featuring Macy Gray (Chesky, 2016) heighten the illusion of an out-of-the-head sound image. If one has an app with a Crosstalk function like the Audioforge Equalizer for iOS devices, one could further enhance said illusion by creating a phantom center image that resides in front of and outside the head, thereby making the sound image more coherent with the absence of that hole in the middle. All my earphones have failed to recreate this illusory image except, to a certain extent, the ZS5 v1. I'm very happy that the C10 places a definite second to the ZS5v1 in its ability to reproduce at least a semblance of such illusion. I swear I could hear Macy Gray's raspy voice floating a couple of meters in front of my forehead for the first few syllables in Annabelle, the first track in Stripped. Likewise, Entrance + Tuning which is the last track in Up Close startled me because I thought someone had actually entered the room—notwithstanding the countless number of times I have listened to it.
