Just in:
ljokerl review of the K2 SP:
Sound (9.4/10) – Billed as a custom monitor in a universal shell, the j-phonic K2 SP is tuned to deliver reference-level sound quality at a more reasonable price and in a more versatile form factor. Its sound differs from conventional stage monitors offered by Westone and Earsonics and slightly less so from flat-response reference sets such as the Etymotic ER4S. The K2 SP is borderline analytical in signature and presentation, and yet its bass offers up power and depth more akin to the dynamic-driver VSonic GR07. The low end effortlessly combines the cleanliness of a TWFK-based earphone with the power of a beefy dedicated bass driver. It is not quite as bassy as the Earsonics SM3 and Westone UM3X, but the low end performs brilliantly overall.
On a technical level there is not much to fault with the lows of the K2 SP – mild sub-bass roll-off aside, it’s got fantastic resolution and articulation, surprisingly realistic note weight, and very good speed. Not only is the low end extremely detailed as a result, it makes some dynamic-driver sets sound underpowered. The bass of the HiFiMan RE272, for example, despite being quick and detailed, simply sounds weak, veiled, and lacking in rumble next to the K2 SP. Compared to the Etymotic ER4S, too, the low end of the K2 SP is significantly deeper, fuller, and more prominent. Of all my current monitors, the dynamic-driver VSonic GR07 is closest to the K2 SP in punch and bass balance, though the softer note presentation makes the GR07 sound a touch fuller, and bassier on some tracks as a result. The K2 is disadvantaged only by the inability to move a whole lot of air – for example it will never sound as fleshed-out and dynamic as the consumer-oriented Sony EX1000 with its 16mm dynamic driver.
The midrange of the K2 SP offers up top-notch clarity and detail, coming across resolving and controlled but at the same time very crisp and edgy. The notes are not smoothed out in the least, causing the j-phonics to sound a bit raw and dry next to the HiFiMan RE272 and ATH-CK10. The clarity keeps up with the ATH-CK10 and ER4S but the note weight of the K2 makes the other analytical earphones sound lean, and yet there is still enough crispness to make sets like the ACS T15 and VSonic GR07 sound slightly fuzzy in comparison. Balance-wise, the midrange of the K2 SP is a touch forward – more present than that of the CK10, for example – and picks up a little towards the top, in contrast to the CK10’s flatter mids. As a result, the K2 sounds a touch brighter up until the treble peakiness of the CK10 comes into play.
The treble of the j-phonics is sparkly and extended, not lacking in emphasis by any means but flatter than that of the CK10. It is clean and clear, never getting smeared, but also integrates into the soundscape better than the slightly splashy, hot highs of the CK10. The K2 is not a forgiving earphone, however, and will point out any flaws in the equipment chain or original recording. Its aggressive nature also will not stop it sounding too clinical for some listeners, and it’s worth noting that it only performs at its best with foam tips, such as the included Complys.
The presentation is perhaps the most underwhelming part of the K2’s sound. The soundstage is very slightly above average in size – hardly congested, but far from spacious. It is well-rounded and engaging but simply doesn’t sound as open and airy as the Sony EX1000, HiFiMan RE272, or even VSonic GR07. Instrument separation, however, is easily on the studio monitor level and the K2 can almost match the imaging of the CK10. It sounds more layered than the Ety ER4S but just isn’t for those expecting an IE8 or EX1000-like headstage. Then again, I don’t see why reference earphones should be expected to have the presentation of a consumer-class earphone. Another reason why the K2 SP isn’t a great pick-up-and-go consumer earphone – it’s got a tendency to pick up hiss and electronic noise so don’t expect it to mesh well with the average smartphone or laptop. A solid audio chain or at the very least a decent dedicated audio player or external DAC will make the j-phonics shine.
