HIGH END REVIEW
Many high-end audio manufacturers say their components have a ‘signature sound’, which you’re going to like or not. But wouldn’t it be nice to be able to change that sound to suit yourself, rather than them?
SACD/CD PLAYER/DAC
Metronome’s AQWO SACDCD Player/DAC is actually part of a trio, because the small French manufacturer decided it would be best to split the cost of the research and development it put into building its first-ever SACD player across an additional two models, which are essentially the ‘building blocks’ of the AQWO. So, at the same time the company was developing the AQWO, it also built a transport, the t|AQWO and a DAC, the c|AQWO. All three are built by Metronome itself in its factory near Montans in the South of France, where it also builds a luxury line under the ‘Kallista’ brand.
The front panel of the AQWO (it’s not a model number, by the way, it means ‘I listen, I hear’ in ancient Greek, according to Jean Marie Clauzel, who’s the General Manager at Metronome), is self-evidently dominated by a massive colour touch-screen display that measures 140 by 70mm. The fact that the screen is so big means not only that there’s plenty of screen real-estate to show multiple icons and read-outs simultaneously, but also that the screen is easy to read, even from a considerable distance. And of course it’s perfect if your eyesight is less than 20/20… and not having that degree of vision, I kind of dislike components that have displays so small I have to be within a metre to read them. The display is inset into the front panel which, I think it worth noting especially, is absolutely massive, being machined from a 20mm thick block of aluminium alloy.
The thickness of the front panel may well be the reason Metronome decided not to put the mains power switch on the front panel, and has instead put it on the rear panel. This is something I’d normally chide a manufacturer about, because in most set-ups it means the switch is difficult to access, but in the case of the Metronome AQWO, the switch will always be easy to access because it’s a top-loading SACD player, so you need to leave plenty of room above it to allow SACDs and CDs to be easily loaded and unloaded, so it will be always be easy to reach behind the AQWO and turn the mains power on and off… particularly since that switch is handily located at the top of the rear panel.
Of course all the other controls you need to operate the AQWO are there on the front panel—it’s just that they’re on that large touch-screen, rather than on the fascia itself. The transport icons are arrayed along the base of the screen, from left to right they are: reverse track skip, fast reverse, stop, play/ pause, fast-forward, and forward track-skip. All the icons are ‘industry standard’ except for the stop icon which is shaped like a bow-tie rather than the more usual square. Curious.
The filter you choose will affect the sound quality of the AQWO, but there’s another option you can choose that will affect sound quality even more.
To the right of the transport controls is the section of the panel where you select inputs, because of course in addition to being an SACD and CD player (plus it will also play discs you’ve burned yourself on CD-R), the Metronome AQWO also functions as a DAC, so it will convert digital signals from another transport, your DVD player, your portable digital player, your computer… indeed from any device that has a digital output. There are seven digital inputs—one USB (via a USB Type B connection), two AES/EBU (via XLR sockets), two coaxial SPDIF (via RCA sockets, and two optical (via Toslink sockets) but no Ethernet socket.
The USB input will accept formats up to DSD512, while the other inputs accept up to 768kHz/32-bit PCM in addition to DSD (anything up to DSD512—or 8×DSD as it’s sometimes known).
The Metronome AQWO uses Asahi Kasei Microdevices Corporation’s Verita AK4497 DAC, the fourth-generation model in its so-called ‘Velvet’ series, which at the time Metronome was developing the AQWO was the flagship DAC in Asahi Kasei’s line-up… and it remained so until late last year, when Asahi Kasei launched its Verita AK4499. Unfortunately, the new flagship DAC cannot be retrofitted to the AQWO, as it’s a 128-pin device, whereas the AK4497 is a 64-pinner.
As with many high-end DACs, the design of the AK4497 allows manufacturers to choose to use one of several different filters, or to permit their customers to choose between them. Quite a few manufacturers select just one filter and do not offer their customers any choice at all, despite these options being available on the DAC. Others offer maybe a choice of two (usually ‘fast’ and ‘slow’) only… and not the full set. Metronome has generously allowed its customers to choose between six options: Sharp Roll-Off, Slow Roll-Off, Super-Slow Roll-Off, Short Delay Sharp Roll-Off, Short Delay Slow Roll-Off and Low Dispersion Short Delay.
Of course if you don’t like the sound of one filter, you can easily switch to another. In practise, my personal experience is that many owners of DACs which offer multiple filters use different filters depending on what type of music they’re listening to at the time—one filter type for classical music, another filter type for rock music, and maybe another for jazz, and so on.
Obviously, the type of filter you choose will affect the sound quality of the AQWO, but there’s another option you can choose that will affect sound quality even more. The AQWO comes standard with a solid-state output stage, however you can optionally choose one that has a second output stage, using valves, which then allows you to switch between the two output topologies. The valves are triodes, and they’re transformer-coupled. At the time of writing, this option added $3,395 to the usual recommended selling price of $27,995, but by the time you read this currency exchange will likely have been affected by the Covid-19 pandemic, so this should only be a price guide.
The solid-state output of the Metronome AQWO uses four Texas Instruments OPA604 FET-input operational amplifiers in Class-A configuration. The OPA604 is an extremely high-quality op-amp with low distortion (0.0003%), very low noise (10nV/Hz) and a high slew rate (25V/μs) plus a gain bandwidth of 20MHz that’s notable not only for being able to natively drive 600 loads, but also for its outstandingly good sound quality.
The valve (tube) output uses a pair of JAN6922 triodes, which are military-spec editions of the 6DJ8/ECC88 valve type and are used in Class-A configuration in the AQWO. Originally designed (by Amperex) for use in radio tuners, the JAN 6922’s high gain saw it being used by Hewlett-Packard and Tektronix in their high-end test equipment and oscilloscopes in the latter half of the last century, while its excellent sound quality saw it being adopted by manufacturers of valve audio amplifiers.
Unlike some hi-fi components that offer the choice of solid-state or valve output, but have separate outputs for each, requiring the user to physically swap cables in order to switch from one to the other, the AQWO does all the switching internally: simply press the ‘soft’ button with an illustration of a valve on it that’s located immediately below the ‘Random’ function at the right-hand edge of the display.
‘Random’ of course, plays tracks on a CD or SACD at random, rather than in the usual play order.
Above this ‘Random’ function is a ‘Repeat’ function that can be set to either repeat a track indefinitely (some may say ad nauseum), or a complete album indefinitely (something I have been known to do, in fact. Some albums are just that good!). These random and repeat play functions, incidentally, are the only programming options available to you—you can’t program tracks for playback in sequence, or cause particular tracks not to be played.
The remote control is black, slim-line and beautifully curvy but is most remarkable for its length: 250mm! If you have a Metronome amplifier, the AQWO’s remote will also operate it, but you will need to select either the ‘CD’ or the ‘AMP’ button on the remote as appropriate in order for it to operate the correct component. It also means that three of the buttons on the remote—‘Vol+’, ‘Vol–’ and ‘Mute’—are redundant if you own only an AQWO.
Installing the AQWO is made dramatically easier because Metronome actually includes a data disc with Windows drivers for the USB and PCM/DSD inputs. At the risk of looking a gift horse in the mouth, it probably would have been better, more convenient, (and less costly) to put these on a USB stick, but I’m not grumbling. And of course if you’re only using the AQWO as a CD/SACD player you won’t need to install drivers at all (neither will you have to if you own a Mac, which does not require drivers at all).
The handsome Owners’ Manual that’s supplied with the AQWO is beautifully presented (and comes with a ‘Certificate of Authenticity’ personally signed by none other than Christian Bat, the CEO of Metronome), but it’s rather light on detail except when it comes to the USB driver installation process and instructions for how to set up the AQWO with Foobar 2000 for DSD playback, where it goes into extreme detail, with step-by-step instructions, all the URLs you will need, plus helpful screenshots. It seemed to me from this that AQWO was recommending Foobar 2000, which is handy, because (a) it’s a good program and (b) it’s free, but when I actually fired up the disc in my computer to access the drivers (yes, I’m Windows), I discovered that the disc not only has Foobar 2000 on it, along with installation instructions, but also the Jriver MediaCentre program, again with installation instructions, so it would appear that Metronome is happy for you to use either program.
IN USE AND PERFORMANCE
I have often been a little put off by the colours some manufacturers use on their displays. One model that I can recall used a rather lurid shade of pink for its display. So initially I was rather excited to hear that Metronome had been forward-thinking enough to allow us to change the colour of the AQWO’s display to suit our personal preferences. However when I started using the machine I discovered this not to be strictly true. It is only the colour of the print on the display that can be changed. The background colour always remains white, and the transport icons always remain grey. The print on the display can be assigned one of eighteen different colours, including a pure black. I ended up using black because although it’s not exactly the sexiest of the eighteen colours on offer, it was by far and away the easiest to read. I found the yellow colour, for example, to be very difficult to read. After you have chosen your preferred type colour, you can then adjust the screen brightness through seven different levels—which includes ‘off’.
Although it’s nice to have this brightness switching, the circuit fitted to the AQWO has an annoying operational quirk which means that if you dim the display accidentally, you then have to cycle through all the different dimming levels before you can get back to the brightness level you wanted in the first place. This is a petty grievance, but one that could be easily addressed by offering a brightness up/down option.
In normal use, the screen shows elapsed time (track) in very large numerals in the centre of the display, while to the left of this is shown the number of the track being played and the total number of tracks on the disc. This is the only information that’s available—you can’t show remaining time in a disc or track, for example, and there is no CD-Text function.
Pressing and holding the large (rather too large, in my opinion) Metronome logo at the top left of the screen causes a second screen to appear, on which you can choose nominal output voltage level (1.4V, 2.5V or 3.5V), your preferred Digital Filter, and your preferred display print colour.
At the top right of this second screen is a tag labelled Input ON/OFF. Pressing this brings up a third screen that allows you to activate (or deactivate) the AQWO’s digital inputs. This means that if you have only one device connected you can deactivate the other five inputs so that you don’t have to cycle through them on the main screen input selector. (You cannot disable the USB input though—this always remains ‘active’ and so will always show as a selectable option on the main screen.)
If the Metronome’s top-loading system is a bit clunky, that will be down to the user, because nothing at all is automated—it all
The sound of the Metronome AQWO is, well… pretty much whatever you want it to be, thanks to the filter and output options.
has to be done by you… by hand. If the lid doesn’t slide back smoothly, you’re not pushing it smoothly enough. If it doesn’t close smoothly, well you’re not pulling it steadily enough. And if the player starts making very strange moaning sounds when you do close the lid, well that’s because you forgot to put the magnetic polyoxymethylene puck/clamp on top of the disc! I guess moaning sounds are better than having the disc fly off the spindle, but it would have been nice if Metronome had included an optical sensor inside the AQWO so it would not even attempt to spin up a disc if the puck/clamp was not present.
Metronome does not make its own top-loading CD mechanisms of course. Although Metronome has used the most famous top-loading mechanism in the past— the Philips CDM12PRO—and still uses this drive in the Kallista DreamOne (thanks to its foresightedness in purchasing a large number of them—together with a shed-load of spare parts—before Philips shut down production), the top-loading mech used in the AQWO is made by D&M Holdings in Japan. It is closely modelled on the DCM12PRO and, like it, uses a twin laser single pickup that houses both a 650nm wavelength laser (for SACD) and a 780nm wavelength laser (for CD) in a single optical system. This technique ensures superior alignment and reduced radiation.
As with all SACD players, it takes a little longer to load a CD than it does an SACD (around 11 seconds for a CD vs. around nine seconds for an SACD) and, once loaded, it takes a further eight seconds to actually start playing music after you’ve pressed the ‘Play’ button. Track skip operations are also fairly slow: if you try to skip from one track to another it will take around five seconds after you’ve pressed the skip button before music starts playing.
It’s all worth the inconvenience and waiting though, because the sound of the Metronome AQWO is, well… pretty much whatever you want it to be, because with six different filters for the digital domain plus the choice of using either solid-state or valve amplification for the analogue domain, the AQWO has twelve completely different and unique ‘sounds’ available to suit your personal preferences, your musical tastes and the other components in your audio system.
I started my listening sessions with a very clean-sounding CD of Davitt Morony playing Bach’s Art of Fugue on harpsichord. It didn’t take very long for me to decide I preferred the sound I was hearing from the solid-state stage over that I was hearing from the valve stage. Listening to the harpsichord via solid-state, the sound of the strings was crisp and truly had the twangy ‘plucked’ sound and I could clearly hear the individual layers of the other strings as they contributed their pitches and resonances. When I switched to valve, I lost a little of the crispness—though the ‘twang’ was still a ‘twang’—but perhaps the biggest difference was that the layering thickened perceptibly, so I felt I was foregoing some of the intricacies of the ways the sounds mixed with each other. Initially I thought this may have been due to the filter I’d started out using (the ‘Sharp Roll-Off’ filter) so I methodically went through each filter in turn only to discover that whilst I did find a filter I liked better (the Slow Roll-off filter), I always preferred the sound quality of the AQWO when it was set to ‘solid-state’… at least I did when listening to this particular disc.
Things were not so clear-cut when I started playing Eleanor McEvoy’s album ‘Love Must Be Tough’ on SACD. Her voice, of course, is unmistakable, even allowing for her accent, and this time I quite liked the added sonic thickness from the valves, which gave her voice added personality, and the instruments a ‘pub-like’ sound quality that I sound most appealing and wasn’t present when I listened via the solid-state output. The almost roundlike way the different instruments take turns on Mother’s Little Helper, for example, minimised the sonic complexity and even with valves I could appreciate the sound of the piano, drums, sax… et al. The same was true for the almost a capella song If You Want Me To Stay, with its deep-pitched drum almost heart-beating in the background.
I then used piano to evaluate the Metronome’s sound, via Chopin Showcase on Move, on which we find Ian Holtham playing Chopin’s 24 Preludes (Op. 28), which is one of my favourites partly because it cycles through the circle of fifths, which I find both intellectually and aurally satisfying. (If you’re into trivia, you should remember that it’s the only work in which Chopin used every key signature, which is a question that’s sure to pop up some time). Holtham’s playing is beautiful and the sound from the Steinway D is absolutely extraordinary.
Through the Metronome, and via the solid-state output, the Steinway’s higher notes sounded gloriously pure, and down in the mids and bass, the richness and sustain was exemplary. Switching to valves actually increased the richness of the sound but at the same time I fancied there was a diminution in the bass, as if Holtham had eased off a little with his left hand. Playing ‘Conditions’ (The Temper Trap), the Metronome AQWO reproduced the sound exactly as I remembered hearing them live, with the band’s etched and crafted sounds delivered to perfection. The sound of the snare sound on Resurrection, as well as that of the drums and other percussion, was rendered exactly. Then there’s the sound of Dougi Mandagi’s soaring vocals—what a voice, and so wonderfully revealed by the Metronome. Again, switching to valve output thickened the sound, but somewhat differently this time, because I thought I could have been listening to a valve amplifier.
Playing music via the Metronome AQWO’s various digital inputs, including comparing rips of the same music I’d played in CD format I found I could tell no difference between CD and the rip of the CD played back via the digital input, so all my same comments about playback from disc also apply to playback via the digital inputs. Playing back higher-res recordings via the USB input certainly improved the ultimate fidelity, per se, but my impressions of the sound of the AQWO remained the same.
And despite the seeming attraction of being able to get ‘valve sound’ at the flick of a switch, I don’t believe it’s a ‘true’ valve sound because a part of the valve ‘sonic’ is the way the valves and transformer interact with the loudspeakers, and that doesn’t happen here. Yes, you do get a different sound, but it’s not the same that you get from a valve amplifier. I much preferred the sound of the AQWO in its solid-state output mode and being able to use the different filters to adjust for the sound quality I wanted.
CONCLUSION
Whereas most people can only dream of owning a Kallista DreamPlay One, the Metronome AQWO is a much more reachable target. For sure, the DreamPlay is a much (much!) better-looking machine, but the two players are of equally high quality, are made by exactly the same company, and whereas the Dreamplay One only plays CDs, the AQWO plays SACDs as well and adds extra value by virtue of being an outrageously good DAC into the bargain. So what about the sound? I have not heard the two players side by side, but I have heard both individually and quite frankly, I don’t think it would be possible to tell the sound of the one from the other in an A/B comparison with the AQWO at its optimal filter setting… at least not when the AQWO is in its solid-state output mode! Which means that here, for the first time, you have a chance to have Kallista DreamPlay One sound quality at a Metronome AQWO price.
Gotta love that!