Resonessence Labs CONCERO DAC
Device Type: Digital to Analog Converter, USB to S/PDIF Converter
Input: Coax S/PDIF, USB Audio Class 2.0
Output: RCA (single-ended)
Dimensions (H x W x D): 7/8" x 4" x 4" (approximate)
Availability: direct online
Price: $599.00CAD, Optional bundle $650CAD includes Apple wall charger and Apple remote
Good Things Come In Small Packages
During my review of the Resonessence Labs Invicta DAC, I thought, to myself, wouldn't it be interesting if they offered just a DAC? Stripped away all of the additional functionality like the preamp, headphone amp and the front-mounted SD Card Reader and gave us just-a-DAC? Well the guys at Resonessence Labs must have read my mind because they've delivered just that (and more).
The Concero is a USB and S/PDIF (Coax) DAC and it can also operate as a USB to S/PDIF converter. The Concero automatically detects if its USB port is connected to a power-only source and switches into S/PDIF DAC mode automatically. You have to provide your own USB power plug and a iPhone charger will do. The Concero can handle up to 24/192 in all operating modes and its a driverless implementation for Mac users while PC owners can download the associated USB 2.0 drivers from the Resonessence website.
The Concero's USB input is Asynchronous which essentially means the Concero controls the flow of musical data from the computer as opposed to the other way around. In slightly more technical terminology, the Concero houses the clock and this control helps to minimize system-induced jitter. As noted, the Concero includes the "digital processing core" of their Invicta DAC, which includes a USB receiver chip from Cypress Semiconductor and the ESS 9023 DAC. The Concero offers three playback modes for sample rates of 44.1kHz and 48kHz (all files over 48kHz play back bit-perfect in their native format)—native bit-perfect resolution, an IIR up-sampling filter, and an Apodizing filter. For the latter two options, data is upsampled 4-times its original rate to 176.4kHz or 192kHz. Here's what Resonessence says about these filters:
Resonessence designed, Minimum Phase, IIR filter
This filter is designed from an analog filter prototype and exhibits no pre-ringing at all. To achieve this, it has to compromise the steepness of the filter; it corresponds to a fourth order analog filter. This is a dispersive non-linear phase filter, but the dispersion has been optimized to the absolute minimum consistent with no pre-ringing.
Resonessence designed, Linear Phase Apodizing filter
Perfectly symmetrical impulse response, hence linear phase and non-dispersive, this filter achieves a high -96db rejection at fs/2 and exhibits the minimum of pre-ringing possible while achieving this excellent rejection.
For much more information on digital filters from Resonessence (especially if you don't quite understand what that quote meant), I highly recommend checking out What are Digital Filters and Why Are They Requried In Today's Audio DACS?.
I also thought it worth asking Resonessence Labs founder Mark Mallinson about why this upsampling was only available for 44.1 and 48 and here's his response:
The custom up sampling is a 4x up sampler so that means a 44.1k goes to 176.4k and 48k goes to 192k. When the data comes in at 176.4k or 192k there is no need to up sample since its already at the higher sample rate. For the 88.2k and the 96k an argument can be made that we should be able to up sample by 2x to get to 176.4k and 192k. However, when we did this there did not seem to be any noticeable difference to the sound. In the end we decided to up sample 44.1 and 48K data rates only.
These playback modes are selectable from an Apple remote (included in the Optional Bundle or $19 through Apple) by pressing the "Menu" button and the Concero's illuminated logo turns color when changing modes from blue (bit-perfect) to magenta (IIR or Apodozing filter engaged). The remote also controls basic playback functions including Play/Pause and Next/Back as well as the brightness level of the front LED, and changing the output to S/PDIF or RCA. I find the Concero to be very well made, especially considering its price, and the simply handsome black aluminum enclosure with the engraved name up top feels cool, solid, substantial, and smooth.
I mostly used the Concero as a USB DAC so the majority of my listening notes will pertain to this functionality. Getting the Concero working was simply a matter of connecting my AudioQuest Carbon USB cable from my MacBook Pro to the Concero and connecting my Auditorium 23 interconnects from the Concero to my Leben CS-300XS. Once connected, I just pointed Pure Music to the Concero and hit play.
The Little Brother Stands On Its Own
Since I no longer have the Invicta DAC here, I cannot say for certain whether or not the Concero sounds just like it. But my admittedly faulty memory tells me they do not sound identical. But lets leave memory and comparisons out of this equation for now and focus on what the Concero sounds like. Of the three operating modes, I found myself continually going back to the IIR Filter (the first magenta). It sounded the most rich and full with a more natural and airy presentation. The bit-perfect mode was to my ears a tad stunted as if some important harmonic and reverberant information was being left out and the Apodizing filter sounded similar to the IIR filter but added some harshness to the overall presentation.
So the first magenta remained lit for most of my listening but remember this applies only to 44.1kHz and 48kHz data. When playing back higher sample rates, that front LED turns bit-perfect blue. I will note this preference between modes was somewhat recording-dependent so having the Apple remote control this choice from the listening seat on-the-fly was a nice feature to have.
The Concero is a very clean-sounding DAC. I know I just said something very similar about the PSB Alpha PS1 speakers I reviewed but that's the way I hear it. Clean and resolute. The perceived 'fatness' of something like the Halide DAC HD is absent from this sonic picture. In its stead we have tons of drive and a very crisp sonic picture devoid of lumps or bumps in the bass but also, thankfully, devoid of any harshness in the upper registers. This combination of resolution without etch is an important point to keep in mind and a rather difficult thing to convey in words (imagine). So there's no fatiguing glare that one typically associates with a crisp, clean and resolute presentation.
I find that this kind of sound picture also loves acoustic music and the more complex the better. High resolution classical recordings are simply stunning through the Concero as are jazz ensembles where wind, fingers, bow, strings, brass, wood, and sticks on skins are responsible for the sounds we hear. On the other side of the coin, grungy rock or lo-fi shoe gaze psych sounds almost too clean, too neat. It's nearly as if you do not want to hear all of the sonic details you get and vocals on poorly-recorded music (like the CD rip of the The Velvet Underground & Nico) sound overly spot-lit and tad too aggressively apart from the rest of the mix. I'm not saying the Concero doesn't work with poorly recorded music, I'm just saying that's what you'll get if that's what you give.
If memory serves, the Invicta was a smoother performer. I recall being very impressed by this aspect of the Invicta and do not have the same level of surprise with the Concero. We are talking about comparing a $600 DAC to a $3,995 DAC/Preamp so that extra $3,000+ must account for something. I wondered if the USB bus-power might be responsible for what I'd call a slightly lean sound overall so I tried augmenting with the i-Fi iUSBPower and was surprised to hear not much difference if any. So I was wrong about the USB bus-power thing.
Let's talk about piano for a minute. I like to play solo piano music when listening critically because it allows you to easily hear sonic anomalies. Artificially heavy left hand, overly chirpy right and sometimes just a mess in terms of locating that piano in space. One of my many favorite solo piano records is Bot-Ba by Giacinto Scelsi featuring Marianne Schroeder on Bosendorfer piano [hatART CD 6092] because its simple (deceptively so) so you can focus in on what everyone's doing, including your DAC. And here, I was completely entranced by Marianne Schroeder and Scelsi from her first note to the last. The Concero handled her very full keyboard with assured grip, lovely sustain, attack worth fighting for, all solidly placed in space. In a word, superb.
As a USB to S/PDIF Converter
For this part of the listening fun, I first connected the Concero to the Mytek Stereo 192-DSD DAC via Coax and to my MacBook via USB. Then I listened and was surprised that the Concero's sonic character traveled with it in this configuration. The Mytek DAC connected via Firewire directly to my MacBook sounded fuller and more fleshed out especially in the midrange. Then I connected the Musical Fidelity V-Link192 USB to S/PDIF converter instead of the Concero and again heard a more fleshed out mid-range as compared to the Concero. Here, some of the Concero's clean and resolute presentation was missing but this was a welcome change on more grungy sounding music. The Musical Fidelity V-Link192 was more forgiving of poorly recorded material like the aforementioned The Velvet Underground & Nico CD rip (a great record btw).
A Family Resemblance
While I've been critical of aspects of the little Concero, its performance in most areas demands that it be taken as seriously as any other DAC regardless of price. Its way with music is assuredly resolute, clean, clear and concise and you get the sense that you're getting what the recording has to give with very little editorializing other than those welcome filter choices for 44.1kHz and 48kHz music. Which filter is most accurate? The one you enjoy listening to since accuracy here equates to which presentation you find most musically engaging. Again, if your record collection and tastes lean towards the loud and raucous, you may want to look at a more forgiving DAC. If you take care with your source material, the Concero will reward you for your trouble.
Overall the Concero is an impressive performer like its big brother the Invicta and I can't help but wonder—since the Concero is based on the digital guts of the Invicta, and the Invicta will reportedly get DSD-capability by year's end, it just goes to follow that little Concero may very well become equally endowed? At its price and given its performance, that would make for one hard to resist package.
Also on hand and in use during the CONCERO review: Mytek Stereo 192-DSD DAC, iFi iDAC, Chordette Qute HD DAC, Cambridge Audio StreamMagic 6, Musical Fidelity V-Link192