Hello Head-Fi! Just thought about sharing some of my opinions on one of Koss' lesser-known canalphones. Introducing the Koss KEB70:
BUILD QUALITY AND UTILITY
The Koss KEB70 is solidly build, with solid aluminum housings, adequate stress reliefs, and a great cable free of microphonics, though I am somewhat concerned about the thinner cords leading from the split to the individual housings. The KEB70 also uses a J-cord / asymmetrical configuration, and while I certainly prefer symmetrical cables, the lightness of the thinner cables, combined with the lack of microphonics, make wearing the KEB70 relatively stress-free. Isolation is also quite good (provided the right tips are used), owing to the completely sealed housings.
The accessory assortment of the KEB70 is relatively simple: three sets of tips, and a nifty, if not smallish, faux leather pouch. The tips included with the earphones didn't anything for me; they lacked a secure fit, which is quite crucial due to the relative heft of the housings, and also resulted in a sound that could only be described as sub-par, lacking in bass and clarity. Once I removed the stock tips (which are quite bothersome to reattach once taken off) and replaced them with some tips from my Sennheiser CX250 (as pictured), the Koss' started showing their true colors.
The KEB70 produces a very pleasant sound: warm, smooth, refined, and laid-back can all be used to describe their sonic characteristics. Bass is slightly soft, with good extension using the CX tips. There is a quite a bit of bass here, though I wouldn't call it overly excessive. Impact is good but slightly on the rounded side. Midrange is slightly recessed and warm, though it retains relative clarity despite the bass quantity. Thankfully there are no noticeable spikes in the frequency response here, as there is absolutely no sibilance to speak of. The treble can also be described as non-fatiguing. There are times where I feel that the highs are slightly lacking in quantity, but what's here is high quality with a good amount of detail.
Soundstage is surprisingly solid for a sealed design. While it doesn't have positioning is decent as is vertical soundstaging. It could use a little bit more depth and horizontal extension, and the bass sometimes makes the soundstage slightly smaller than it should be, but I'm just nitpicking here.
The Koss KEB70 are a great choice for those seeking a well-constructed, warm-sounding earphone on a tight budget. While the relaxed signature may not be suitable for all, the KEB70 provides good sound quality and a lifetime warranty for just under $20.