Yuin PK2 Earbuds (not ear-canal) Stereo Earphone review

Discussion in 'Headphone Reviews' started by dalethorn, Mar 6, 2016.

  1. dalethorn

    dalethorn Obsessive Auditor

    Jul 3, 2011
    Charleston South Carolina
    Youtube review:


    Sources: iPhone6s+ with Oppo HA-2/FiiO K1 DAC/amps, various computers using the Audioquest Dragonfly-2/HRT Microstreamer/FiiO E17k/FiiO E07k DAC/amps.

    Review notes: My first impressions of the sound of the Yuin PK2 are based on direct comparisons to other earbud earphones, particularly the erstwhile audiophile types, but also to a few premium headphones for reference. I'll describe how I relate to the PK2 (i.e., my personal tastes and how I use the earphone) only after covering all of the objective issues. Note that since the PK2 is very bass-light, used without earpads**, my analysis of the sound will utilize equalization via the iOS Audioforge app and the Windows Foobar2000 digital music player. The PK2 was purchased from Massdrop on 05 Dec 2015, order number MD-13660-792067, for $42.24 USD.

    **The tiny thin foam 'earpads' supplied with the PK2 earbuds have not proved useful to me, since in trying to mount them they've torn apart. Based on my last experience with such 'earpads', they do almost nothing to improve the sound. I have a Yuin PK1 on order now, and I will review that earbud when it arrives. Hopefully it will have a better bass response. Still, the PK2 sounds fantastic with the EQ I've applied, so I highly recommend it for users who are willing to do likewise, or experiment for themselves.

    The PK2, even when equalized, has a light mid-bass and essentially no usable low-bass. The PK2 would not be my first choice for EDM or pipe organ** music, but the overall sound is very smooth with surprisingly good voice and instrument tonalities. I've said this before in other reviews, but it applies to the PK2 as well: If I had only one earphone to use for the next year and the PK2 was that earphone, I'd find it enjoyable (with EQ) for 90 or more percent of listening I do - mostly pop, jazz, classical, rock, and new-wave. The EQ'd bass sounds very decent on most of my tracks, the mids and treble are well-balanced, but what sets the PK2 apart from most other earbud earphones is its more-or-less hi-fi response, as compared to the usual shrill or spoken-voice-oriented earbuds.

    **The last half of the 20th century saw a move toward the construction and/or restoration of tracker organs, i.e. the mechanical-action organs similar to what Bach and others used. In my experience, tracker organ recordings don't typically exhibit much power in the deep bass below 40 hz, and they can sound pretty good on earbuds like the PK2.

    The last question on sound quality, given the PK2's basic signature, is whether the sound is smooth (no major peaks or recesses), whether the tonality is accurate (voices and instruments sound natural), and whether an audiophile volume level with strong dynamics causes any distortions. The PK2 sounds natural enough, takes a fair amount of bass and/or treble boost, and still plays loudly with no discernible strain or distortion, so it gets my recommendation given the caveats noted above. Isolation is nearly zero, so important musical details will be obscured in noisy environments. Leakage on the other hand is so low that the PK2 should be useful in libraries and quiet work places, even at audiophile volume levels. Finally, while I love the sound of the PK2, my estimation of its signature is based on the notions that my outer ears won't influence the sound much differently from other users, and that other users won't use the tiny thin 'earpads' or something similar that has a significant effect on the sound.

    The very thin cables going from the 'Y' to the earpieces are not detachable, and don't appear to have any strain reliefs where they connect to the earpieces. The word I've heard from some users is that they can be fragile, so great care must be taken to ensure that the cords aren't yanked or otherwise subjected to abuse. The total length from the standard 3.5 mm terminator to the earpieces is about 4 ft. There are no controls like those that are used with smartphones etc. The PK2 comes in a small plastic cylinder packed with the tiny thin 'earpads', and the cylinder is inside a small wood-like box about 2.75 x 2.75 x 2.375 inches in size. There's a small fold-out instruction, and all of the writing appears to be in Asian language graphic characters. I carry my PK2 earbuds in a small flat leatherette case made for small generic IEM's.

    In previous reviews I've included the following music examples with comments about how the earphones sound with each track. My suggestion is instead of reading each one as an absolute unto itself, you could compare my notes here to those other reviews and see how the PK2 compares with each individual track.
  2. dalethorn

    dalethorn Obsessive Auditor

    Jul 3, 2011
    Charleston South Carolina
    Animotion - Obsession (1980's New Wave/Techno): The upper bass synth has excellent detail and tone, and both male and female vocals sound natural without favoring either. The PK2 plays this extremely well.

    Bauhaus - Bela Lugosi's Dead (~1980): Strong midrange sound effects - this is a good worst-case test for resonant-type sounds in the most sensitive midrange area. Handled perfectly by the PK2.

    Beethoven Symphony 9, Solti/CSO (1972): Excellent overall sound. Of special note here are the bass impacts beginning around 10:30 of the fourth movement. Those impacts are soft and well in the background, and you can almost feel the weight they carry with the PK2.

    Black Sabbath - Iron Man (Classic Rock): Very good instrumental detail and the vocal sounds very natural. As with most classic rock tracks, there is very little or no deep bass. The PK2 plays this music very smoothly, and the lack of deep bass doesn't unbalance the treble.

    Boz Scaggs - Lowdown (1976): Great sound quality - this is a good test for any nasality in the midrange. Handled very well by the PK2.

    Cantus - Danny Boy (Traditional/Male Choral/Acapella): The PK2 plays the voices with a minimal low end warmth that supports the lower register of the male voices on this track.

    Cath Carroll - Moves Like You (1980's New Wave/Techno): This track's percussion and voice are crisp and well-balanced, and there's a good sense of space or soundstage around the voices and instruments. The PK2 reproduces the space and detail very well.

    Catherine Wheel - Black Metallic (~1991): Goth with industrial overtones - I like this since it's a great music composition and the sound effects are smoothly integrated into the mix. This may sound distorted or mushy with some headphones, but the PK2 renders the deliberate instrumental distortions clearly.

    Chris Isaak - Wicked Game (Pop/Rock): The PK2 plays this high treble energy recording very smoothly - the voice and instruments are very detailed but not edgy - very musical in fact.

    Chromatics - I'm On Fire (Synth-Pop, female lead): This track has a good amount of space around the voice and instruments, making for a very pleasant stereo image. The voice is excellent, and the tambourine sound is clearly identifiable.

    David Hazeltine - Fur Elise (Jazz): A very high-quality recording from HDTracks. The PK2 reproduces the instruments smoothly with a spacious ambiance. The wire-brush-on-cymbal harmonics are very extended and detailed.

    Grieg (Beecham-Royal Philharmonic) - Peer Gynt-Solveig's Lullaby (Classical): This very old (late 1950's) stereo recording must have been made on the most expensive gear in the world, since the overall sound quality and especially Ilse Hollweg's amazing voice are as close to "being there" as I've heard with some of the better classical recordings made since the year 2000. The PK2 plays this music perfectly.

    Hans Zimmer - Dark Knight-Aggressive Expansion (Soundtrack): The percussion in this track hits really hard, and while the bass tones beginning around 0:45 should have the ultra-deep "shuddery" kind of sound that indicates a solid deep-bass response, the PK2 bass is very light. Still, the PK2 plays this music very well.

    Heaven 17 - Let Me Go (1980's New Wave/Techno): The bass instrument (guitar?) has excellent detail, and the voices and ambiance have a "you are there" quality that's uncommon in early 1980's pop music. The PK2 plays this track near-perfectly.

    Hugo Audiophile - 15-16 (Electronic): I'm not sure what the 15-16 stands for - perhaps track numbers from a CD album. The deep-bass tones that start around 33-34 seconds into the track are very subtle with the PK2. This is a great recording for evaluating whether a headphone's bass will be sufficient for most environments, since for many headphones that have a weaker bass, the deep bass gets absorbed and mostly lost when the environment contains a lot of low-frequency energy.

    Jimmy Smith - Basin Street Blues (early 60's): This track has several loud crescendos of brass and other instruments that don't sound clean and musical with some headphones. The PK2 provides excellent reproduction when EQ'd. Listen particularly to the second crescendo at 15 seconds in for best-case detail. I'd like to emphasize that these crescendos are probably the worst-case test I have for instrument separation and detail, and the PK2 does those well.

    Kellogg Auditorium, Battle Creek Michigan, Aeolian-Skinner Organ (1933) - Pedal, 32', Resultant, Arpeggio: This 16 hz organ pedal tone differs from other music tones in that you won't "hear" the tone - you'll only feel it. Although most music tones have harmonics (including this one), the harmonics from this tone will be too weak to provide any "feel", so whatever you actually hear would not be part of the fundamental 16 hz tone. There are ~30 hz sounds in the outdoor environment in big cities, generated by large trucks, buses, and subway trains, and they have a quality of "rumble" that's similar to some deep-bass tones found in music. This 16 hz organ tone is easily distinguished from those sounds when compared on a headphone that has good undistorted response at 16 hz. The PK2 plays the fundamental with extremely light weight.

    Mantovani - Sunrise Sunset (Easy Listening, ca. 1972): A master musician and conductor** who specialized in light classics and orchestral pop music, Mantovani's accomplishments were overshadowed by music critics who couldn't tolerate the notion of "light classics" or "semi-classical" music, even when those recordings were no threat to the classical music genres. In any case the later Mantovani recordings from the mid-1960's through mid-1970's had the advantage of being mixed for much better hi-fi systems than those which the music critics possessed at the start of the Long Playing (LP) record cycle. Here in 2015, at least some of those digital remasters have improved the sound further, although it's not always the case. This track as played on the PK2 is a perfect example of the sheer musicality lurking in those later recordings, and is highly recommended for soundstage, instrumental tone, and musical balance.

    **Mantovani developed the "Cascading Strings" sonic effect circa 1950, a famous "Wall of Sound" effect for mono hi-fi systems that predated Phil Spector's own famous Wall of Sound effect by 10 years or so.

    Michael Tilson Thomas - Rhapsody In Blue (20th Century Classic): Great sound and soundstage, and terrific piano playing and tone. There are some very deep bass impacts starting around 38 seconds into the 17:24 length track, and the weight of those impacts is extremely light with the PK2.

    Pinback - Non Photo Blue (Pop-Rock): Crispy sound with "crunchy guitars and bashing drums" - the PK2 renders this music as perfectly as I've heard an energetic pop-rock recording played with any headphone.

    Porcupine Tree - Trains (Pop-Rock): This track opens with some nicely-detailed string sounds and a forward-sounding male voice with a higher-than-average register. There are a series of "clip-clop" effects starting at 3:19 that should sound like they were made with wooden blocks of some kind. The PK2 reproduces the 'clop' portion of that sound pretty well.

    Richard Strauss (Mester-Pasadena) - Also Sprach Zarathustra (opening) (Classical): The granddaddy of bass is in the opening 1:50 of this recording, and I've heard it only once on a large and expensive loudspeaker system in Cleveland. For most people, that experience would be indistinguishable from being in a fairly strong earthquake. The PK2 conveys some of that drama with a bass boost, but very little when played flat.

    Scarlatti-Kipnis - Sonata in E Major K381 (Classical, Harpsichord): The harpsichord here is fairly bright and highly detailed, and the PK2 renders the tones and transients well.

    Tiger Okoshi - Bootsman's Little House (Jazz): The trumpet here is recorded fairly close up and is somewhat bright with a significant "bite". The PK2's reproduction is near-perfect, and the close-miked piano is also a treat. For comparison, I have several Maynard Ferguson tracks that feature a similarly strong trumpet with lots of brassy bite.

    Trombone Shorty - Backatown (Jazz-Funk): The deep bass impacts here are extremely light, but the overall bass works well with the horns and other instruments. The PK2 delivers the bass with good detail, and the horns have the kind of bite that gives them a wonderfully realistic sound.

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