So, I've been threatening to do a bit of a review of the Sennheiser 660s for some little time now, but it seems like it took me FOREVER to find the time to do so.
I'm tossing this out here to the 58X discussions because, essentially, the Jubilee and the 660s are very close to being the same headphone, the drivers are virtually the same with the exception that the 58X drivers are, I believe, 2mm smaller.
I'm going to,(for me), be a bit more brief in this review..... selecting only a couple of musics for the listen, and sticking to 2 amplifiers; the Woo Audio WA2 and the JDS Labs The Element. In this I can address how these sound on both a tube amp and a solid state dac/amp.
By now, most people probably know what is meant by the essential Sennheiser "House Sound", which tends to be, in many of their offerings, a somewhat more forward bass without being muddied, having a moderate bass-veil that does not rob the cans of detail and mid-to-high range clarity. With the exception of the HD600's, one generally cant describe the sound as being neutral, and many folks find the Massdrop-Senn collaboration 6XX's, the HD650's and onward to be good for gaming and more bass-present-preference listens. I'm a solid HD600 aficionado myself, having a love for a more neutral sound that is presented with clarity and detail, yet not sterile or particularly clinical sounding,(as can be the case with Beyerdynamics cans).
The 660s and the Jubilee are a bit of a departure from the Sennheiser House sig, (and build), but not glaringly so. The drivers are built differently from the old standard; you can read the specs on this product description or go to Sennheisers own spec sheet for details,(like impedance, ease of driving, and graphs), so I won't be laying that out here.
These are a touch more clinical sounding,(a slight lean toward the BeyerD SS), yet there is a sweetness to the presentation with beautiful clarity and a smoothly present-without-being-overwhelming bass. These are very clearly not the cans for "bassheads" ; I would not recommend them for dub or gaming, if you really want that overpowering shatter-your-core pound to your sound, for instance.
The musics; I spent a lot of time listening to Glaciation by Patrick O'Hearn and the Bachianas Brasileiras by Villa Lobos, specifically the much celebrated live concert recording of #5 by Anna Moffo in 1963.
I chose these for the following reasons; The O'Hearn album offers a great deal of nuanced and non-digital electric instrumentation that is meditative in nature and where you have presented to you tiny sounds like finger-squeaks on electric guitar strings, the minute pluck of a bass as the only percussion in most pieces.... an almost oozing slice of ice down a mountain-side, as the album title describes. O'Hearn is a bassist, so you know that bass will be present in his recordings, yet he never overwhelms the other instrumentation with it. In some ways, it's nearly jazz.
The Bachianas Brasileiras are a series of nine suites by the Brazilian composer Heitor Villa-Lobos, written for various combinations of instruments and voices, #5 written for an orchestra of 8 cellos and a solo female soprano. With this I am offered soaring soprano vocals backed by the depth of 8-cellos and all that breathing and fibre that goes with this performance.
Listening to the O'Hearn, I am immediately taken by the capability with which these cans are graced in offering up each separate note.....detail, nuance, precision...... each nearly dripping note is sublime. The limited percussion,(sparse, meditative cymbals, and brushed snare), is presented crisply and CLEARLY. I am offered a sense of that ever elusive head-space and instrument placement.....I've read other peoples reviews of these remarking that these headphones can be shrill or overly sparkling in the mids-to-highs, maybe somewhat fatiguing; not my experience, after AMPLE run-in*. There is a mildly sparkling sweetness to the high end, almost reminiscent of the Grado 325 metal-backs,when amped correctly. Lower range extends beautifully.
The Villa-Lobos is admirably presented, again these 'phones demonstrate the vocals and strings very capably and in a very enjoyable way with great detail, yet without harshness.(The BeyerD's can go that road, unless correctly amplified, so I have a comparison available to me for that happening.) One really does get a sense of placement, one hears the intake of breath, the visceral understory from the cellos.
Amping; The WA 2 amp is a VERY nice compliment to these more neutral set of cans, rounding and mellowing what some have described as "shrill"....with The Element solid state amp, in the early sessions I found the lack of the tube-amp "liquification" of the sound to be a little fatiguing. After the cans were "stretched" for a couple days, I found that The Element presented these cans much more appealingly and with great accuracy. Neither amp was overwhelmed by the 660S's demand for adequate power.
Comfort; these are going to feel like the HD600 etc. for fit and the comfort of extended listens. If you have worn the HD600 or 6XX and so on, you know what these feel like. I'm 3 hours in on a session,(while typing here), and I'm not hot or "saddlesore".
The Take-away; If you like a more neutral-yet-nuanced set of headphones, the Sennheiser 660S and the 58X Jubilee might just be the ticket for you. The 58X Jubilee puts a beautiful sound signature within fiscal reach for everybody, while I, a true fan of the HD600 found the expenditure on the 660S totally worthwhile. I also very much love the BeyerD T1 and the DT880,(which I use for musics that demand a more clinical sound),........ I think I can best describe the sound I'm getting from these as being kind of a unique blend of the Senn and BeyerD sound. Kind of a "best of both" version, if you will. Certainly an extension of the Sennheiser line-up.
If you are willing to give these a SOLID run-in before you sit down for a focussed session, I think you will find these pleasing and satisfying for extended listens of Acoustic, Jazz, Live Classical, Studio.
Detail,Clarity, Accuracy, and Range....with, perhaps, an understated-yet-nuanced Bass probably best describes the sound sig of these headphones.
At the 58X price-point, definitely worth a try.
Hope this helps, if they re-drop the Jubilee, or if anybody is curious about trying the 660S.
* AMPLE run-in/burn-in is going to be important to allow these to optimally present themselves. I found that the sound really was MUCH improved after 2-3 days of proper run-in.