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After hooking up the Rosetta 800/Big Ben combo, I began with a totally unfair comparison. I played back a stereo acoustic guitar track that was previously recorded on a DAW using an M-Audio Delta 1010 interface clocked by a Lucid GenX6,  just to hear the Rosetta 800’s D/A quality. I played it back through the Delta 1010, and then through the Rosetta 800, using powered monitors that were directly connected.

Even though the Delta 1010 is a respectable box in its class, this was Bambi vs. Goliath II. I knew that the Rosetta 800 would be superior – I just wasn’t prepared for how much better it would be. Even though the source material was recorded through the Delta 1010, it had clarity and and depth playing back through the Rosetta 800 that was completely missing through the Delta 1010, which was muddy by comparison. But that’s to be expected when you pit a five-year-old $600 interface consisting of a PCI card and a breakout box versus a $2,995 brand new state-of-the-art dedicated converter box.

So, rebounding from that pitiless comparison, I staged a fairer fight. The best D/A converters I have are in a Tascam MX-2424 with the $1,500 analog card installed. I’ve always like the sound of these converters, and they’re pretty well balanced across the spectrum. I used the same stereo acoustic guitar track, which I exported from SONAR as a broadcast wave file. Again, both the Rosetta 800 and the MX-2424 were connected directly to powered monitors. It was a decent match, but the Rosetta had little trouble pulling ahead. This is the point at which definitions become more difficult, but in all the categories outlined above (warm, rich, full, natural and detailed), the Rosetta 800 was demonstrably better.

But for me, the real Acid Test was how the Rosetta 800/Big Ben performed while recording. Even though the quality of digital conversion in and analog conversion out are equally important to producing a great mix, the audio is torpedoed at the gate if the A/D converters are subpar. You can never replace the missing information -- you’re stuck with what you’ve got. On the other hand, it is technically possible to make a great mix with lesser D/A converters, even though luck will be needed also because you’re not hearing everything accurately while you make mixing decisions.

For reference, I used the Tascam MX-2424, and Apogee’s own Mini-Me, a portable mic preamp and A/D converter reviewed here earlier. In each case, there was a distinct improvement in imaging and clarity when using the Rosetta 800. Here’s where things got interesting. An acoustic guitar recording made with Rosetta 800/Ben Ben in the chain sounded eerily real on playback (again with the Rosetta 800/Ben Ben). That may not sound like much of an accomplishment, but think about it. You could still tell the difference by listening intently, but …

The recording chain consisted of a Martin Acoustic miced with a matched pair of Groove Tube GT-33 condenser mics, going into a high-quality Elberg MP-8000 mic preamp and then into the Rosetta 800 analog input. An  X-Y pattern was used for the mics, one of which was aimed at the 12th fret and the other aimed at the soundhole.

Before we go any further, we should note that a skilled musician is the Most Important Element in the recording chain. Playing the guitar was Darryl Marini, who is not famous but may well be soon. He’s an acoustic and electric guitar maestro, and a great songwriter to boot, whom the world may hear someday if we ever finish recording what promises to be a killer album (end of shameless plug).

The objective with the Rosetta 800 was to add a big-sounding 30-second acoustic guitar solo to a 20-track song containing lead and background vocals, drum kit, bass, stereo acoustic guitar track, etc., etc. Instead of recording one simultaneous stereo track, Darryl opted to record the left and right channels as separate takes that would be mixed together. First, he played a beautiful and complex solo, recorded in mono by the left panned mic. And then -- because he can -- he doubled it, with the right-panned mic recording the doubled take. The solo culminated in a high slide and pull-off riff that made me turn around to see how he played it, because it sounded like a sitar.

This was a good test of the Rosetta 800’s ability to handle two independent signal paths simultaneously, converting the analog acoustic guitar track to digital, feeding it out via a mixer to the recorder, while converting the recorder’s digital output to analog and sending the signal to the monitors.

A Mackie digital mixer was used essentially as a digital router in this path, bypassing its converters. The Rosetta 800 output was to the Mackie’s ADAT in card, which digitally routed the incoming signal to the appropriate channel on the MX-2424 hard disk recorder. The recorder’s 20 previously recorded digital tracks went back through the Mackie, and were submixed to a stereo signal through the Master 1&2 bus outs to the Rosetta 800’s ADAT in. Finally, the Rosetta 800’s analog outs went to Blue Sky 2.1 monitors for playback. Recording was done at 24-bit/48kHz resolution.

SoftLimit button (middle) on Rosetta 800's front panel

I engaged the Soft Limit button (available on all eight analog inputs), which provides analog tape-type rounding of transient spikes. This is designed to allow several more dB of signal to be recorded digitally.

When the two acoustic tracks were combined, the slight variations in the performances created a haunting natural delay effect. And the Rosetta 800 delivered a hyper-enhanced sense of presence. Soloing just the two acoustic tracks (muting the rest of the mix) resulted in a gorgeously rich acoustic guitar sound. It was marked by intense clarity in the high frequencies and round full-bodied low-frequency sounds  Some pyschoacoustic factors, high harmonics, overtones and subtle fret noise were in evidence, and no doubt there were others that couldn’t be consciously heard. There was sparkling clarity in the individual notes of strummed guitar chords, yet the chords’ natural sound and warmth were retained. This kind of presence and definition is what separates great audio converters from adequate ones.

In fact, the Rosetta 800/Big Ben combo gives all the instruments in a mix more definition, both individually and as an ensemble. A bass guitar recorded through the Rosetta had audible high harmonics in a mix, in addition to low-end presence and detail. Overall, the stereo mix sounded more three-dimensional.

Sonically, Big Ben’s contribution was to make the Rosetta 800’s sound even smoother. I removed it from the chain and substituted a Lucid GenX6 clock, and definitely preferred the sound with Big Ben in the chain. It wasn’t bad with the Lucid, just better with Big Ben.

Big Ben is built around a new technology called C777 that produces “virtually unmeasurable” jitter, according to Apogee. Low-jitter clock signals are one of the most important elements of great conversion. The Big Ben’s manual sums up this relationship nicely: “The overall quality of a digital system is determined by the quality of the A-to-D and D-to-A converters; the most stable clock possible ensures the most consistent timing, and therefore the highest quality, for these stages.”

AES and S/PDIF connectors on Big Ben. Optical is also provided.

As mentioned previously, Big Ben’s digital routing capabilities can come in handy. I generally record at 24-bits/48k, so to record to CD, the signal needs to be downsampled and dithered. The Rosetta 800’s UVHR22 internal dithering process does a great job of smoothly dithering down from 24 bits to 16 bits … but the signal still needs to be downsampled from 48k to 44.1k. I have a handy little Z-Systems sample rate converter, but it has S/PDIF connectors, and the signal from the recorder is ADAT optical. The solution was to take the recorder’s optical out to the Rosetta 800, from there to the Big Ben’s optical in, and finally from the Big Ben’s S/PDIF out to the Z-Systems unit. From there, the signal finally went to the CD recorder. Phew! But it worked flawlessly, once I figured out that to use the digital format converter you must sync Big Ben to an external signal, in this case, ADAT optical.

Even with only eight channels of AD/DA, a typical 24-track (or more) multitracked session can be done entirely through the Rosetta 800’s converters. You can record a complete drum kit including left and right mic overheads through the eight analog-to-digital converters while simultaneously recording scratch tracks of a bass or vocal that aren’t going through the Rosetta 800. After the drums are finished, you can then go back and do final takes of other instruments using the Rosetta 800. For most project studios, this represents no change in the usual multitrack procedure. (For users who need more than eight tracks of simultaneous conversion for larger live sessions, Apogee’s new 16-channel units with Big Ben’s C777 clocking technology built in have just begun shipping.)

Considering the conversion quality of the Rosetta 800 and Big Ben combination first, and the routing capabilities and limiting/dithering features next, this combo should satisfy nearly anyone. Used individually, each box performs admirably on its own. But as members of a team, they truly shine.