Eclipse TD508Mk3 and TD520SW 5.1 System Review

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by Ed Selley Apr 7, 2015 at 8:16 AM

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    Highly Recommended
    Eclipse TD508Mk3 and TD520SW 5.1 System Review
    SRP: £5,500.00

    What is the Eclipse?

    After some time spent away from the nitty gritty of reviewing and attending to some minor issues like the total overhaul of the site, our very own Phil Hinton is back in harness and has been reviewing some of the most talked about speaker packages on the forum. Looking over his review of the XTZ Cinema Series, it is clear that these are crushingly competent speakers and I suspect that the next package he has in for review is going to be similar. If you have a reasonable budget for a truly mighty AV speaker package, logic dictates that you would look towards these designs.

    Allow me if you will to present something a little different. This is another high end sub/sat AV package and it is being tested in a 5.1 configuration. After that the similarities end. This is a package that spends as much time trying to solve performance issues solely of its own making as it does showing its performance advantages. It has design aspects that border on the obsessive and- perhaps most contentiously- it costs two thousand pounds more than the XTZ.

    The manufacturer of this ensemble is Eclipse, the Japanese company famous for their single driver 'Time Domain' speakers has spent many years overcoming the simple physical limitations of the use of a single driver. Part of this has extended to the design of active subwoofers to complement the speakers and augment their bass. As the satellites are identical to each other and the subwoofer boasts some solid performance figures, it stands to reason that a multichannel pack should be fairly interesting. Does Time Domain offer any advantages for AV use?

    Design principles

    Eclipse TD508Mk3 and TD520SW Design principles
    I have covered much of the principles of the single driver technology that Eclipse uses in my earlier review of the TD-M1 desktop system so I won't go into a full rehash here. The TD508Mk3 is larger than the TDM1 but works on exactly the same principle. This means that an alarmingly small driver (given as 8 centimetres but in reality if only the radiating area is considered, rather smaller than that) is called up to produce every frequency you are going to hear until it hands over to the subwoofer.

    The advantages to doing this are significant. Making the multiple drivers of a conventional speaker work together is an exercise in compromise and damage limitation. Choosing the frequency cut points, securing a decent phase performance and ensuring the different drivers- often made of different materials with different radiating and resonant characteristics- is a genuine challenge. A single driver should be tonally even and with no crossover involved, the performance should be exceptionally cohesive.
    Eclipse TD508Mk3 and TD520SW Design principles
    You will note a few uses of the word 'should' in that paragraph. This is because if these theoretical benefits were easily achievable in the real world, everyone would be doing it. That driver- small or otherwise- is being pushed to frequencies that are well beyond any normal driver of the same size so it has to be extremely light. It then is being asked to extend down to 60Hz (Eclipse claims an absolute roll off of 52Hz) which is totally at odds with the requirements of treble production. This means that every design aspect of the TD508Mk3 is devoted to keeping the laws of physics at bay long enough to do this. The driver is bolted to a heavy metal mass anchor that ensures that all of its excursions are converted to sound rather than wasted through resonance. The whole enclosure is damped and tweaked and cajoled into helping that single driver produce the required extension.

    Neither is the egg shape a design quirk. Having extracted the required frequency response from the driver, Eclipse is equally focused on realising the supposed benefits. The TD508Mk3 is designed to most accurately repeat an audio signal as seen as a measured wave. The egg shaped form is the least sonically intrusive means of doing this while achieving the required extension.

    This means that the appearance of the Eclipse is not willfully quirky but they do look fairly unusual. I like them- especially in the black- and so did a number of people that passed through the house but equally a number of people felt that they were entirely odd and slightly unsettling. Three finishes are available- white (actually a metallic flake effect and much nicer than I thought it was going to be) silver and black.

    What about the sub?

    Eclipse TD508Mk3 and TD520SW What about the sub?
    Next to the 'Pixar lamp meets jet engine' appearance of the TD508Mk3, the TD520SW is almost conventional but other than being a cube pretty much everything else is as radical as the passive speakers. Having built speakers designed around the principle of phenomenal response times, any attempt to augment their bass extension had to have the same reactive speed as the passive speakers. Eclipse needed a 'fast subwoofer' and in their legendarily obsessive way, set out to create one.

    The TD520SW is the smaller of two active designs. The first design decision Eclipse took is one we have seen in a few subs over the years. The larger the driver, the greater the lags from inertia as it changes direction. As such, the TD520SW uses a pair of 8 inch drivers in a counter firing arrangement. The twin 8 inch cross section is roughly that of a single 12 inch. These two drivers work in phase back to back. This is normal enough but after that normality steps aside.
    Eclipse TD508Mk3 and TD520SW What about the sub?
    The two drivers are decoupled from the cabinet and the necessary rigidity is achieved by an aluminium shaft which holds the drivers in what effectively looks like an outsize dumb bell. Like the full range drivers in the passive speakers, these drivers are designed to be as low a mass as the requirements of generating bass allows to increase response time. The cabinet itself is then as inert as possible. The TD520SW is only 40 odd centimetres in any given direction but weighs a substantial 37kg. The Eclipse is therefore a deadweight chassis with two featherweight drivers contained inside.

    In a market where rivals can dispose of over a kilowatt to move a single driver, the 250w output of the Eclipse seems a little on the low side but the company is completely adamant that this is all that is required. The amp is at least one of the most reliable and effective subwoofer powerplants- a B&O ICEPower module which means that the TS520SW also runs cool in use.
    The final area of design curiosity is the inputs. Eclipse's desire to make the TD520SW as fast as possible doesn't end with the mechanical design. In order to shave milliseconds off the driver response, the TD520SW can be used without any form of crossover on the sub at all. Even when a sub crossover control is maxed, therefore allowing the amp to judge the crossover, the physical wiring remains. The Eclipse can switch it out altogether allowing the drivers to start fractionally quicker. You can then also have a second input that allows for a stereo amp (that probably won't have a crossover) to use the Eclipse and for you to select crossover values for that.

    What's good about the Eclipse System?

    Most high end multichannel is fairly bulky. The Eclipse- weighty sub aside- is usefully compact. It is flexible too. The TD508Mk3 is as happy being mounted on a wall or ceiling as it is being used on a table or stand. There is also a dedicated floorstand available. This is a system that isn't much harder to accommodate than any normal sub sat system.
    Eclipse TD508Mk3 and TD520SW What
    Eclipse TD508Mk3 and TD520SW What

    It is also beautifully built. The 508 review samples have led a busy life but still look and feel gorgeous. The sub is a wonderful combination of precision and heavy engineering. It manages to look and feel special in a way that many more conventional speakers can't. The plethora of inputs on the sub aids flexibility and it also comes with a full function remote allowing for correction on the fly which is hugely useful.

    What's not so good about the Eclipse system?

    If we leave the looks as a bit of a personal thing, the Eclipse is not without some minor challenges. The TD508mk3 has a nominal sensitivity of 82dB/w which is amongst the lowest of any dynamic driver speaker on sale today. Equally, as the TD508Mk3 is designed around a maximum input power of 30 watts, this means that if you have a big room to fill they aren't going to work. In reality, I found myself working the not inconsequentially powerful Yamaha RX-A3040 quite hard to reach 'normal' listening levels so don't think you'll get away with a cheap AV receiver.

    This has to be factored into the cost because the Eclipse is hardly being given away as it is. At £500 each, the TD508's are fairly pricey but this pales next to the £3,000 asking price of the TD520SW. This is a system that treads the rather niche path of needing buyers with deep pockets but rather small rooms. This being the UK though, there are a few of those.

    Eclipse TD508Mk3 and TD520SW
    A single driver should be tonally even and with no crossover involved, the performance should be exceptionally cohesive

    How was the Eclipse tested?

    The TD508mk3s were placed on Soundstyle ZT60 stands with the exception of the centre which was on a Quadraspire QAVX rack. The sub was placed in the rear room position as the size didn't allow for use at the front. Equipment used was a Yamaha RX-A3040 AV Receiver, Cambridge Audio 752BD blu ray player, Sky HD and a Panasonic GT60 Plasma all connected to an IsoTek Evo 3 Aquarius mains conditioner. Test material included blu-ray, broadcast and on demand TV, catch up services, as well as lossless and high resolution FLAC.

    What does it sound like?

    Eclipse TD508Mk3 and TD520SW What does it sound like?
    Short answer? Quite unlike any speaker package I've ever heard at any price. To unpick this daunting statement takes a little explaining so bear with me. Having spent some time with the TDM1, I had a basic grounding in what the Eclipse sound is all about. The whole reason for the speaker to exist and the reason Eclipse accepts the low sensitivity, limited bass extension and slightly directional nature of the sound is because they are startlingly accurate operating in their comfort zone.

    The 508 is actually even more direct than the TDM1 and this means that the performance honestly takes a little bit of time to get used to. I personally tend to prefer 'fast' speakers where the driver, either through high sensitivity or low mass needs little time to move and change direction even if this robs the frequency extremes of a little energy. This is why I use Elipson Planet Ms as my usual AV speaker and Neat Momentums as my stereo ones- both have this speed. The Eclipse is in a different league though. The human brain is a curious thing and honestly the fractionally shorter time that the Eclipse needs to get going genuinely aids the sense of realism.
    Eclipse TD508Mk3 and TD520SW What does it sound like?
    When you marry this to the exceptional tonality that the Eclipse has, you have a system that doesn't so much generate sound as beam information into your head. Watching Fury with the Eclipse only a few days after I had done so with the Acoustic Energy 1 Series was especially illuminating. The Acoustic Energy is a brilliantly sorted set of speakers and it manages to make sense of the combat sequences and keep the events on screen relatable to those sounds happening around you. With the Eclipse, any ambiguity is gone entirely. This is the soundtrack exactly as prescribed with absolute speed and control and entirely free of lag, delay or confusion. My Wife, slightly flippantly, christened the effect 'God mode' and for better or worse, it stuck for the time they were here.

    All of this would be completely irrelevant if the bass underpinning these lightening fast satellites couldn't match them but the obsessive attention to detail that has gone into the TD520SW has honestly produced the most extraordinary sub I've ever listened to. The 520 is a racehorse in a field of Suffolk Punch's. It can't hit as hard as many rivals- it is effectively out of ideas at just the point where the SVS SB13 is getting ready to go to town on your internal organs- but the way it can go from total silence to potent wave of deep, clean bass is quite unlike anything else I've ever found on the market. The detail, subtlety and nuance of the bass it produces makes most other subs sound like blunt instruments. It is utterly and totally addictive.

    While I find this performance captivating, I wouldn't be doing my job if I didn't point out the problems because they are there and depending on your preferences and requirements they may be a significant issue. The first is that the Eclipse is heavily directional. Where the front three speakers of many packages throw a vast wall of sound with a barely perceptible handover to one another, the Eclipse is not like this. The handover between the identical drivers is excellent but there isn't a huge soundfield around them which does tend to mean there is a fairly clear sweet spot to enjoy God mode. The sensitivity issues also mean that the 508 never goes biblically loud and also tends to become a little subdued at lower levels- their ideal performance envelope is rather narrower than some rivals.

    Eclipse TD508Mk3 and TD520SW
    The detail, subtlety and nuance of the bass it produces makes most other subs sound like blunt instruments

    What does the Eclipse sound like with music?

    Eclipse TD508Mk3 and TD520SW What does the Eclipse sound like with music?
    I have spent the time I have been writing here bemoaning that subs are not truly suitable for music. I'm pleased to report that after several years of trying, if you happen to have three grand burning a hole in your pocket, this statement is no longer entirely true. As a 2.1 system, the Eclipse is seriously good. The same utter lack of delay that works so well with film material is equally effective here and that superb midrange on the 508 has the ability to make pretty much anything sound utterly magical. There is undoubtedly a loss in treble energy compared to a speaker with a dedicated tweeter but the 508 manages to go high enough with sufficient refinement that I haven't missed having a dedicated high frequency drive unit while they were here.
    Eclipse TD508Mk3 and TD520SW What does the Eclipse sound like with music?
    The 520 integrates perfectly with the 508s and matches them blow for blow. Nothing I threw at them, be it complex syncopated rhythms, massed orchestra or the layered peculiarity of Boards of Canada fazed it. It manages to do the most significant thing that a subwoofer can possibly be asked to do; it imperceptibly augments the speakers it is partnered with while itself disappearing from your perception. If it doesn't do that straight off the bat, the remote allows you to rapidly tweak the settings to allow it. As a trio, I rate it on a level with my Neat Momentums and given those are still my favourite stereo speakers for less than £4,000, that is pretty high praise.


    OUT OF


    • Exceptional detail retrieval and response
    • Impressive tonality
    • Truly exceptional subwoofer


    • Hard to drive
    • Lacks absolute volume
    • Presentation has a definite sweet spot
    You own this Total 0
    You want this Total 0
    You had this Total 0

    Eclipse TD508Mk3 and TD520SW 5.1 System Review

    Like football punditry, this is a conclusion of two halves. Objectively, the Eclipse balances some quite incredible abilities with flaws that may or may not completely rule out their use for many people. Many speaker packages at this elevated price point do a convincing job of being all things to all people and the Eclipse is a long way from that. This is not a Reference product and nor is it a Best Buy. These speakers have some impressive attributes but they exact a high price- both literally and figuratively to do so.


    If these attributes are the same ones you strive to find in equipment though, there is a very high chance that absolutely nothing else will do. During the review period and after an extended evening of listening (and it must be said, drinking beer) I posted on Twitter that this was a BC/AD moment for me in terms of multichannel audio and I genuinely mean that. Everything that comes after these speakers has to be judged in the light of their existence and the astonishing way that they process information. Be under no illusions that if I could stump up for their significant asking price, I would be doing so. Everything else has now been Eclipsed.

    Suggested retail price when reviewed: £5,500.00

    The Rundown

    Sound Quality


    Build Quality


    Value For Money




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