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Sunday, January 1, 2012

Home Recording Studio Review!
Benchmark ADC16 DAW Converter:
The Ultimate in Multichannel Accuracy




Brevis...

Price: $$3,995
Likes: pristine A/D, connectivity
Dislikes: Absolutely nothing
More info: Benchmark ADC16


by Jackson Macinnis


Benchmark Media has designed reference quality professional and audiophile products for nearly 20 years. The reference quality ADC1 and DAC1 series of converters are some of the best digital converters on the market.
Recently, Benchmark introduced its $3,995 made-in USA, ADC16 A/D converter which kicks analog-to-digital conversion up to a higher level of performance for all kinds of recording studios — especially today’s professional-grade home studio.
The Benchmark ADC16 fits 16 channels of its premium converters into a single rack space — yet still manages to fit AES/EBU, ADAT, coaxial and TOSlink connectivity. It even contains an expansion port for a Firewire port DAW interface, which is how I used the ADC16.

Features
As I mentioned, the ADC16 contains plenty of user features, considering it is one rack-space high and wide. The front panel consists of several pushbutton controls, indicators and nine-segment meter for each channel. It sports a clock output control, sample-rate selection, AES digital output control, SPDIF digital output control and optical output control (ADAT or SPDIF).
The 16 nine-segment meters are easy to read and their scale is adjustable via the front panel push button. The peak hold function is adjustable. The ADC16's front-panel switchable sample rate control — with press and hold functionality — is a real handy feature. I’ve seen entire systems in a studio crash by someone fat fingering a sample rate on a convertor/clock. The ADC16 operates at the standard 44.1 kHz to 192 kHz (always 24-bit), as well as non-standard sample rates for broadcast and cinema production work.
The key to the Benchmark's flexibility is the input/output architecture. First, the balanced analog inputs are via DB-25 connectors. Eight channels per each of its two DB-25 input banks, which means you will need your sources to have the correct output cables with DB-25 connector to interface with ADC16.
Output wise, there could not be a better interface for a multichannel A/D. The ADC 16 contains eight SPDIF coaxial outputs, (two channels per output), eight optical outputs (two channels per output), and sixteen channels of AES/EBU out via DB-25 connection, 2 x 8 channels. The Benchmark also is fitted with word clock output and input for external synchronization purposes.

I played a Gibson Custom Shop ’59 Les Paul, which has a fantastic warm humbucker tone. I have recorded this rig with other converters, but the Benchmark ADC16-recorded tunes played back through the DAC1USB (or even my Apogee DAC) blew them all away. I have never heard my guitar rig sound this good...

Key for today’s computer DAW compatibility, the ADC16 features a card slot for interfacing via computer protocols, such as Firewire. Also, it can also accommodate other future formats as well, such as USB-3, etc. The review unit came with a Firewire card that enabled as many as 16-channels of digital output. (For someone who has a DAW without any hardware, the Firewire interface offers the flexibility to simply plug-in and still have this level of quality and the 16 inputs.)
The primary A/D design is based on the stereo reference ADC1 A/D, using the excellent-performing AKM 5394 A/D stereo ICs (eight of them), as well as high-quality digital clocking and analog components throughout the audio path. Unlike the ADC1, the ADC16 utilizes synchronous conversion for seamless compatibility for all sample rates.
Benchmark also has improved the already impressive jitter reduction via its new proprietary clock-sync system, which is termed UltraLockDDS. This upgrade to the previous Ultralock technology is said to reduce audible jitter — even if using an external clock reference — and the ADC16 does it with reduced latency, which has been noted in the previous generation.

The unit also features a word clock output; if you have an expanded system with a separate digital board and other units, you could not do better than locking everything to this unit. Use of its jitter-free, house clock source alone is a great reason to buy this converter. As with the ADC1 two-channel A/D, the ADC16’s specs are impeccable. Signal to noise and dynamic range greater than 120 dB, jitter is almost nonexistent. (See the SpecCheck measurements at the end of the review).
Although the ADC16 has major utility for home studios, it is also designed to work in other professional scenarios including television studios, film production and dubbing stages. The use for reference audio of this specification is endless. With its number of channels, connectivity and performance, the $4,000 price tag is a bargain!


The setup
For this review, Benchmark provided the Firewire card-equipped ADC16 as well as a DAC1USB D/A for stereo monitoring. Setting it up was fairly straight forward and not difficult at all. The Firewire option installation required the use of a Pico driver, which installed with no issues in the 8-core Xeon Apple Mac Pro that I used for the test. Once I launched Apple’s Logic and created an aggregate device I was able to use the ADC16 for my inputs and the DAC1USB for monitoring the mix down stereo outputs. Pretty darn slick setup.
I used a variety of microphones, Mogami cable and our esteemed publisher, John Gatski, loaned me his British-built ORAM 16T 16-channel analog console. As the front end to the system, this $4,000 console contains quiet, dynamic mic preamps, which are easily accessed through the direct outputs. We used a quarter-inch, balanced TRS-to DB-25 cable to get the audio from the ORAM mixer to the ADC16.
The audition
My first recording test was a fairly standard drum setup. I used a Shure Beta 52 on kick, a Shure Beta 57 on snare, an overhead mic arrangement consisting of a Rode Nt-4 stereo and Neumann U87 and two Cascade Fat boys ribbon microphones for room pickup. I left the analog trim pots at their factory settings, using the ORAM 16T’s individual channel-gain faders, which kicked out plenty of analog signal level.
The drum kit playback of the stereo mix down (24-bit/192 kHz through the DAC1USB) was truly amazing: smooth, quiet and warm, yet very dynamic and real sounding. The Benchmark definitely had more detailed nuance (cymbal reverb tail, etc.) than when I used an Apogee multichannel converter.


The quality of the A/D output, when listening to the stereo mix down via the Benchmark DAC1USB, revealed to me one critical element: to hear the ultimate sonic detail from the ADC16, you need a DAC capable of delivering what the A/D has laid down on disc.

I cranked up the playback to listen for any signs of that gritty high-end edge that is typical in lesser converters — and even cutting-edge units from ten years ago. I never heard any audible crunchiness from the digital system. I suppose we have come to a new age when even the last analog hold outs will be swayed by the dynamic, yet smooth character of digital PCM through a Benchmark converter. There is no way you could say this ADC sounds “digital.” I used to be one of those people that labeled digital as “digital sounding,” as if it were a curse, but the transparent realism of the ADC16’s sonic character is mind blowing.
After listening a bit more to the impressive clarity of treble and midrange tones (cymbal decay and the hi-hat), I focused on the low end. In digital, good-sounding, low-frequency music reproduction has always been easier to eek out of the digital converters than the top end. But in the case of the Benchmark A/D conversion, I heard so much more definition than I expected in the kick. The tones were low, no inherent thinness. It was reproducing exactly what we sent it from the ORAM mic pre-amps. And isn’t that the point? Isn’t that what we strive for as recording engineers? The sound of the music as it is heard live by the studio engineer and performers. Unlike other devices that we use to color sound, the highest compliment for an A/D converter is that it has no color — no artifacts; this accurate character is exactly what I found with the Benchmark ADC16.

The key to the Benchmark's flexibility is the input/output architecture. First, the balanced analog inputs are via DB-25 connectors. Eight channels per each of its two DB-25 input banks, which means you will need your sources to have the correct output cables with DB-25 connector to interface with ADC16.

Next up were vocals from a musician friend who played acoustic guitar and played a few songs for me. I used a Neumann U87 on the singer’s vocal and a stereo Rode NT-4 for the acoustic guitar. Again, I was immediately struck by both the lack of digital edge in the mids and treble and the presence of the vocal — so full and live.
I am so impressed how real sounding these Benchmark converters are. Yes, the ORAM mic pre-amps are outstanding and contributed to the positive recording experience for this review, but without the Benchmark A/D converter in the mix, the recordings were not quite as detailed or dynamic. And just think, if you have good mics and preamps, the ADC16 gives you have this kind of recording quality using just a computer and some software in your home studio!
The last thing I recorded was an electric guitar, using a Cascade Fathead ribbon microphone as a room mic and a mic close to the Fender Vibro-King amplifier. I played a Gibson Custom Shop ’59 Les Paul, which has a fantastic warm humbucker tone. I have recorded this rig with other converters, but the Benchmark ADC16-recorded tunes played back through the DAC1USB (or even my Apogee DAC) blew them all away. There was such body and fullness of tone; I have never heard my guitar rig sound this good on tape. Oops, I mean disc.
I had no real qualms or problems with the ADC16, operationally or sonically. There was a wee bit of learning curve in the beginning to get the ADC to communicate with Logic, but a quick read of the very detailed manual had me up and running in no time.



The quality of the A/D output when listening to the stereo mix down via the Benchmark DAC1USB revealed to me one critical element: to hear the ultimate sonic detail from the ADC16 you need a DAC capable of delivering what the A/D has laid down on disc. Oh sure, you can hear quite a bit of the realness from the ADC16 from an Apogee or other brand of DAC, but the Benchmark stereo DAC brings it out even more. Speaking of DACs, a companion 16-channel DAC is coming soon from Benchmark — which means killer multichannel A/D and D/A. I can’t wait to hear that one.

The verdict
I used the ADC16 in a home recording studio — where all levels of artists from garage bands to the well-known artists do their recording these days — and it excelled beyond my high expectations. The finest A/D conversion I have ever heard is through the ADC16. And it is easily available (for just under $4,000 of course) to those who simply want to plug a unit into a computer and make tracks as good as any world class standalone studio. Who wouldn’t want this?
Many artists that do their recording at home sometimes need to go to a larger studio to track drums or do any expanded ensemble work since they have invested in only a few inputs in their home systems. The ADC16 allows them to setup an entire band and fill a multi-track session in a single take — with the best sound quality. If ever an audio product deserved the Everything Audio Network Stellar Sound Award, it is indeed the Benchmark ADC16. Jackson Macinnis is chief engineer and director of the Sirius|XM recording studios in Washington, DC. He also is a multi-instrumentalist musician and home audio recordist who composes music for TV and film at his home studio. He can be reached via the Everything Audio Network.


©All original articles on this site are the intellectual property of the Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited.
EANSpecCheck:
Benchmark ADC16 A/D Converter
Tests Run by BHK Labs, 12-21-11


The Benchmark ADC16 is versatile A/D converter with a wide selection of sample rates, output formats, and connection possibilities to normal analog inputs and/or to a DAW with an added accessory card. Measurements were made to analog inputs 1 & 2 with a reference input level of 12V rms set as 0 dBFS which was just shy of onset of clipping.
Frequency response at 0 dBFS at sample rates of 44.1, 88.2, and 192.0 kHz is shown plotted in Fig. 1. Filter shapes are such that the response is quite flat up to the onset of filter roll-off. Low frequency response was flat to below 10 Hz. An interesting and revealing measurement in digital converters is the THD+N vs. level of a 1 kHz tone in the converter output where the input ranges from 0 dBFS down to a sufficient low level to reveal the noise floor. In the case of this design, the noise floor is an impressive approximate -120 dBFS but the distortion takes quite a reduction of input level to get there – approaching 0.0001%!. This is plotted in Figure 2 for both channels and sample rates of 192.0 and 44.1 kHz. The results (not shown) for sample rates of 88.2 and 96.0 kHz were closer to the 44.1K data. The higher amount of THD+N is for the 192.0 kHz sample rate.
THD+N vs. frequency at full scale was reasonably constant over most of the audio range rising a bit in the last two octaves. This data is shown in Figure 3 for sample rates of 192 kHz (Magenta), 96.0 kHz (Red), and 44.1 kHz (Blue). The S/N ratios at the digital outputs for sample rates of 44.1, 96.0, & 192.0 kHz and in a measurement bandwidth of 20 kHz were 119 dB for all three sample rates. Dynamic range measurements for the same sample rates were also 119 dB.
Finally, for the three sample rates, quantization noise was -118 dB. Adjacent channel separation was excellent, similar in both directions, and better than 106 dB even at 20 kHz. All in all, the basic measurement parameters of the Benchmark ADC16 are in or near the top of A/D converter performance standards — numbers that we come to expect from this engineering-driven electronics company.


—Bascom H. King





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