I always look forward to hearing new closed back headphones. Their design implies important tuning challenges in comparison to open counterparts, with cup reverb introducing questionable, sporadic frequency response quirks, along with a distracting sense of timbral incohesion that makes most models unintentionally eccentric.
High end closed backs, which usually isolate poorly in comparison to IEMs, make weak arguments for purchase given their design targeted at home use, a context in which less restricted open backs are typically appropriate. Upon listening to countless sealed models through the help of show demos, personal ownership and avid audiophile friends, anticipation would usually be followed by disappointment. No matter the price range, one word always came to mind: compromise. I have rarely ever considered a closed headphone to offer good value, and even less commonly thought them worth owning long term.
A few years ago, some friends in a vintage headphone exploration phase laid their hands on the Sony MDR-CD1700. Knowing them as potentially harsh critics, they recounted positive experiences with it, making it somewhat of a curiosity for me ever since.
History, Design & Ergonomics
This biocellulose headphone was preceded by the legendary MDR-R10 (1989), a proof of concept for this unorthodox material’s implementation in headphones, with the less expensive MDR-CD3000 coming along two years later. Both were plagued with reliability issues mainly due to tightly mounted and fragile voice coils that sheared under the drivers’ repetitive excursion. Indeed, I recall witnessing Kaldas Research’s founder, Aumkar Chandan, having both his R10 and CD3000 drivers failing within a span of weeks – an appalling tale.
Introducing a newly developed 50 mm driver composed of biocellulose embedded into a polymer substrate called “Vectran”, the CD1700 was Sony’s flagship from 1996 to 2000. Costing 25000 JPY at launch, this equated to $230, or $390 corrected for inflation, it can nowadays be found used for around $150-250 – much less than its predecessors. With a low impedance of 32 ohms and a high sensitivity of 106 dB/mW, it is easily driven by most sources. The hardwired single-entry 10 foot LC-OFC cable on my pair was substituted for a detachable 3.5 mm solution by a friend of mine, Zerousen, creator of the increasingly popular PhilPhone. Please note that there have been different revisions (black or white baffle paper) that are said to sound different – my pair is white, but I am unsure how it sounds relative to others.
This Japan-made rarity certainly won’t impress through its build quality. Despite the use of aluminum in the ear cups, headband pleather flakes away and creaky plastic forms a yoke with potential failure points. Nevertheless, through its light weight of 325 g distributed on a wide, self-adjusting head strap, light clamp and soft, breathable velour ear pads, it remains exceptionally comfortable through extended listening sessions.
The Sony MDR-CD1700 is, in my opinion, a thoroughly enjoyable headphone – my pair’s only acoustical modification is removal of a disintegrating foam disk covering the driver. It excels through its cozy tuning whereby a minor mid-bass bump is followed by a warm-tilted midrange and relaxed treble in a manner that exudes some of the finest balance I have heard in any closed back.
Despite Sony’s pioneering efforts, biocellulose drivers have only recently been popularized by Denon’s AH-D line and Fostex’s TH series, which typically offer thunderous, yet tight and remarkably articulate bass. This is, however, not the CD1700’s style. Rolling off around 50 Hz, with a conservative mid-bass hump, it delivers extension that bests most open dynamics, but is certainly not bottomless. Low end is bloomy and soft in texture, failing to demonstrate the authority and speed of the basshead classics previously mentioned. Still, the extended decay imparts a sense of richness to the overall presentation – bass lines are liquid, yet not particularly one-notey or flabby. While some may prefer a more linear, clean and dynamic presentation, I thought the lush, reverberant lows of the CD1700 played finely into its laid-back approach.
Richness further extends into the midrange, which is the star of the show. Closed backs usually fall prey to inconvenient bumps and dips at various parts of FR that often make things wonky. Yet surprisingly, the CD1700 uses this restriction to its advantage, offering a delicately tuned, warm-tilted presentation that remains mostly linear. Lower midrange displays concretely slow-decaying fundamentals. This is followed by a tastefully light middle midrange resonant bump that imparts romantic “honk” to vocals. Leading edge is blunted and notes are weighty, making this an evidently sweet-sounding headphone. Whilst instruments are globally rendered smooth, a slight sense of bite can nevertheless break through in higher registers before dipping around 2-3 kHz. This minor inclusion of grain does transmit a slight sense of textural incoherence that is typical of closed backs, but that hardly shakes my high esteem of the CD1700’s captivating tonal and timbral characteristics. I am dazzled by its ability to convey a natural acoustic performance. Soft guitar plucks reverberate generously, piano strikes are thickened and hefty, yet high-pitched brass can still exhibit zing through the upper midrange resonant characteristics.
Whilst I enjoy this, it certainly isn’t for everyone. There is an undeniable sense of haze that will turn away those who seek technical prowess. Detail retrieval is respectable, but resolution is middling and layering gets fuzzy on busier passages. Dynamic contrast is decent, but there certainly are snappier headphones that will deliver sharper, more potent attack (beryllium driver Focals immediately come to mind). The stereo image is intimate, but despite the respectable depth it offers, this won’t project the diffuse staging of cavernous closed backs such as the JVC HA-DX10000 or MDR-CD3000.
Top end is undeniably relaxed on the CD1700. Some of the upper midrange textural grit is present in the lower treble, manifesting itself as added tang to cymbals, which counters its overall FR recession relative to midrange. Extension is also proper, preventing it from sounding too stuffy. However, this isn’t a particularly airy or sparkly headphone, at the possible cost of excitement. Top end resolution is similarly appropriate but will fail to impress demanding listeners. The CD1700 does its job but pulls no fancy tricks in the treble – and I didn’t care.
Frequency response measurements
Here is how the MDR-CD1700 measures on my MiniDSP EARS. Keep in mind that this is only an approximation, as there are more accurate measurement rigs out there.
I used the CD1700 on my main desk stacks: a Dangerous Music Convert 2 DAC into a Bryston BHA-1 solid state amplifier (sharp, dry and dynamic) and a Bryston BDA-1 DAC into an Apex Sangaku nu-tube hybrid unit (warmer, bloomier). While this headphone’s microdynamics scaled well on the DC2/BHA stack, I found myself reaching more for the BDA/Sangaku combo, which further enriched lower registers and helped polish its upper midrange textural grit. That being said, its high efficiency allows it to be appropriately driven by most sources.
I purchased the Sony MDR-CD1700 a year ago and was charmed at first listen. Its mellow yet versatile tonality was an invitation to dive deep into various parts of my music library, and its intangible fluidity with top tier comfort provided many care-free hours of listening pleasure. To spread the joy, I sent it on an extended loaner tour to some friends. Whilst happy to read their impressions, I found myself dearly missing its imperfect sound.
As it recently returned from its trip south, I rediscovered its agreeable essence. While this headphone certainly won’t enthral everyone, no closed back has generated this level of charm for me. In a market where my experiences were marked by a natural progression of hope to disillusionment, the Sony MDR-CD1700’s unassuming elegance mollified my analytical approach…
… leaving ample place to appreciate the diversely marvellous art of music.