Field Test: Apogee Electronics Rosetta 800
Mar 1, 2004 12:00 PM, By Michael Cooper
The Rosetta 800 ($2,995), Apogee's newest 24-bit multichannel converter, offers eight channels of A/D and D/A conversion, flexible sync capabilities and Apogee's proprietary UV22HR wordlength reduction and Soft Limit dynamics processing. Although the 800 bears the Rosetta name, the new unit uses different converter and clock circuitry than the original 2-channel Rosetta 96 A/D. The Rosetta 800 shares many analog design improvements from Apogee's high-end SE (Special-Edition) converters and functions (including D/A conversion and the ability to sync to external clock) that are not found in the original Rosetta.
A ROSETTA BY ANY OTHER NAME
Three D-sub connectors provide eight channels of balanced (+4dBu) analog and eight channels of AES/EBU I/O (supporting both single- and double-wide formats). Optional XLR breakouts are available. Two pairs of Toslink connectors provide eight channels of ADAT- or S/MUX-format ins and outs.
A rear option card slot accommodates Apogee's X-Series Expansion cards ($595/each). The X-DigiMix card provides direct interface to Pro Tools TDM PCI cards. X-HD and X-FireWire cards should be available next month. Word clock I/O (on BNCs) and a detachable IEC AC cord round out the rear panel. The word clock input is non-terminated; users should fit a terminated T connector on this input when slaving Rosetta 800 to external word clock.
The 800 can sync to internal crystal, external word, single/double-wide AES/EBU, ADAT Lightpipe (including S/MUX) or option card clock signals. The unit supports up to 96 kHz, but a $3,995/base 192kHz version is offered. Rosetta 800 can operate at any sampling frequency that's a multiple of where its word clock input is locked. It can also output word clock at a rate multiple of which its converters are operating.
Two simultaneous 8-channel audio streams — one routed to digital outs, the other to analog outs — are possible with flexible routing. For the first multichannel stream, you can route analog ins simultaneously with digital ins of any one supported format in channel pairs to corresponding channels of digital outs. (All digital outs are active; the 800 automatically handles format conversions.) The second multichannel stream accommodates analog and digital sources (one digital format at a time) routed to like-numbered channels of analog outs in channel pairs.
Apogee's UV22HR processing can be applied globally to all digital output signals to reduce word length from 24-bit to 16-bit. Soft Limit processing (proprietary analog domain dynamics processing) can also be applied globally to all analog inputs or disabled. Soft Limit can't be activated independently for each channel. That said, the processing sounds incredibly transparent. Apogee's Soft Limit is easily my favorite analog limiter.
All eight channels have signal presence and “over” LEDs, although power users will bemoan the lack of external calibration trims. Only three fixed calibration levels are possible. The default is +4 dBu = -16 dBFS. Internal jumpers provide two alternatives: One calibrates +4dBu levels to -20 dBFS, and the other produces -13 dBFS for semi-pro -10dBV levels. This limits the choices for analog input sensitivity, but still offers headroom. Very quiet sources required at least 65 dB of external preamp gain for the 800 to achieve 0dBFS peak readings. Apogee plans to offer a retrofit calibration pot card that would fit over jumpers; however, accessing the card's trims will still require popping the top panel.
For one test, I sent a kick drum track — previously recorded in Digital Performer — on a round trip through the Rosetta 800's D/A and A/D circuitry. The Rosetta 800 reduced — by a hair — the lower midrange frequencies in the processed track; otherwise, the track copy was indistinguishable from the original. The difference was so subtle that it was almost inaudible. Performing the same A/B test with a flamenco-style nylon-string guitar track, the original track had slightly more depth than that processed by the Rosetta 800's AD/DA. These tests confirmed the uncanny accuracy of the 800's converters.
More tests involved recording a capoed acoustic guitar using a spaced pair of DPA 4011 condensers with a Millennia HV-3D preamp, and on an electric bass guitar using a Millennia TD-1 Twin Direct Recording Channel. With each box synched to its own internal clocks, comparing the A/Ds in the Rosetta 800 to my Rosetta 96, I found that the 96 sounded a bit fuller in the lower mids, more understated in the lower highs, and exhibited a slightly wider stereo image and a tad more depth. The 800's (A/D and D/A) dynamic range spec is 114 dBA, although the depth that I heard suggested a more impressive number. The 96's A/Ds sounded a little more fluid and analog-like on acoustic guitar than those in the 800, perhaps due to the 96's slightly greater depth and fuller low mids. On electric bass, the 800's A/Ds made the track sound present, clear and tightly focused, while the 96 produced a more soft and pillow-y sound; the two yielded a very similar bottom end.
Up next were recorded acoustic guitar tracks. When I synched the Rosetta 800 to Apogee's Big Ben Master Digital Clock, the tracks had a sweeter, more fluid high end, a slightly wider stereo image and a noticeably enhanced depth compared to those recorded with the 800 synched to its own internal clock. The combination of these two boxes sounded downright incredible.
The Rosetta 800 sounds outstanding and offers useful features and functions beyond AD/DA conversion. Every bit worthy of the Apogee name, the Rosetta 800 is a winner.
Apogee Electronics, 310/915-1000, www.apogeedigital.com.
Michael Cooper is the owner of Michael Cooper Recording, located in beautiful Sisters, Ore.
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