FIG. 1: The Apogee Rosetta 800''s logical front-panel layout helps make it an easy converter to use.
After dealing a winning hand with its affordable Rosetta 2-channel converters, Apogee has upped the ante by producing an 8-channel version. The Rosetta 800 offers 24-bit, 96 kHz multichannel A/D/A conversion for analog, ADAT or S/MUX optical, and AES/EBU signals. To facilitate multiple-format transfers and simultaneous A-to-D and D-to-A processing for a computer or MDM recording system, the Rosetta 800 also offers independent switching and conversion for its separate digital and analog signal paths.
Low-jitter clocking, UV22HR dithering for 16-bit output, and Soft Limit analog input limiting are standard features on the Rosetta 800. External word-clock sync in and out is a new addition to the Rosetta. And if that weren't enough, all this digital firepower is housed in a single rackspace unit, graced with an uncluttered control panel.
The First Reading
The Rosetta 800's gleaming brushed-aluminum face is adorned with Apogee's familiar purple highlights, and the layout is a triumph of simplicity with clear menu functions and only seven switches across the bottom (see Fig. 1). Each switch-selectable menu option is printed in black and has its own LED indicator. The logical layout makes the Rosetta 800 easy to use right out of the box.
On the front panel's far left is the AC power switch, and, in a departure from convention, the LED for that control is lit when the unit is off. The first multiple-option menu is Sample Rate, with indicators for 44.1-, 48-, 88.2-, 96-, 176.4-, and 192 kHz and a green EXT LED for selecting external word-clock sync. AES/EBU signals at 88.2 kHz or higher can be run as either single-wire or double-wire (DW) connections. Using the Rosetta 800 at 176.4 or 192 kHz requires an optional factory modification, which adds $1,000 to the list price.
The WC I/O Sync menu is enabled and lit only when the EXT function is selected from the Sample Rate menu. That grouping has all connection options: ADAT (44.1 or 48 kHz), ADAT + S/MUX (88.2 or 96 kHz), Option (optional card slot), AES, AES DW, and WC (word-clock in).
The Rosetta 800 uses a dual-stage clock to reduce jitter, and the lock status of the clocking circuit is displayed to the right of the WC I/O Sync selector. Wide lock is confirmed when the green cone shape is lit, and narrow lock is indicated by a red LED directly beneath it. The net effect of a verified wide and narrow lock is not only confidence that your signal is clocking accurately, but also a cheery green and red exclamation point beaming from the panel.
The next section governs source selection for the digital outs. As with the WC I/O Sync menu (and the Source to Analog Out), the menu choices are uniformly laid out. Sources to route to digital outputs include ADAT, ADAT + S/MUX, Option, AES, AES DW, and Analog. A blinking LED indicates that a selected digital input source is either not present or not properly synced. It is also possible to assign a combination of analog ins and one digital source (limited to 1-2, 3-4, 5-6, and 7-8 channel pairs) to the digital outs, using switch combinations outlined in the manual. Additional switching options associated with digital output sourcing are Soft Limit (on/off for all eight analog inputs only) and 24- or 16-bit dithering using Apogee's UV22HR process (on/off for all digital outputs, 44.1 or 48 kHz only).
Located on the panel's far right, Source to Analog Out uses the same menu as the digital out selections: ADAT, ADAT + S/MUX, Option, AES, AES DW, and Analog. As with the digital output section, it is possible to route analog-to-analog output along with a single digital input source on that menu.
A basic metering area separates the digital and analog output menu sections. Each channel (1 through 8) has a pair of variable-intensity LEDs to indicate analog and digital output levels, along with an LED to show analog-to-digital overload. These A/D Over lights help with power-user setups for combined analog and digital source routing.
When using the Rosetta 800 to perform independent digital and analog conversions, the same word-clock/sampling rate (or multiples thereof) must be used. Word-clock out is always the same as word-clock in.
FIG. 2: The Rosetta 800 uses 25-pin D-sub connectors for analog and AES/EBU digital I/O.
In addition to a standard IEC power connector, the rear panel has word-clock I/O on BNC jacks; multipin analog input and output, and AES I/O on 25-pin D-sub connectors; and optical ADAT or S/MUX I/O (see Fig. 2). The Rosetta 800 does not support 2-channel optical S/PDIF signals, even though the manual states that it will interface with a DAT machine through the Toslink bay.
The Option card slot on the rear panel accepts Apogee I/O cards including the Pro Tools X-HD ($595), the Pro Tools X-DigiMix ($595), and the X-FireWire ($595), for use with Mac OS X and Windows XP computers. Apogee also manufactures multiconnector D-sub-to-AES/EBU and D-sub-to-analog XLR cables for the Rosetta 800.
Unlocking the Secrets
During a period of a few months, the Rosetta 800 was used at my Guerrilla Recording studio as either the main or supplemental D-A output converter on several Pro Tools mixes for commercial release. Those sessions covered a range of rock, world music, electronica, and jazz instrumentation.
For studio use, the Rosetta was reliably quick and easy to set up. It connected seamlessly with the optical ADAT outputs from a Digidesign Digi 001 interface. Always sonically neutral and never fatiguing, the Apogee converter made my preferred method of computer mixing — from Pro Tools through an analog board and hardware — a delight. Adding the Rosetta 800's eight outputs to the Digi 001's ten outputs is a cost-effective method of getting 16 or more discrete 24-bit channels out of a basic ProTools LE setup. For 24-bit mixing sessions, I'm generally pleased with the quality of the Digidesign Digi 001's analog outputs. But after a series of A/B comparisons, it became clear that the Rosetta 800's 8-channel converter offers significant improvements.
On a variety of digitally recorded sources, the Rosetta 800 was unquestionably more dynamic, adding depth and realism to individual tracks. Foreground mix elements were much more lively and present through the Apogee unit, creating a dramatic relief from the flatness that is often attributed to digital recordings. It was also easier to appreciate the detail and dimension of low-resolution background sounds through the Rosetta 800.
With superior conversion of this type, every instrument in a mix sounds better. And the boost in subtle details enhances an overall spaciousness that makes it easier to distinguish and savor each mix element. In the testing I did against the Digi 001, the Rosetta worked some extra magic on percussive sounds. For example, the Rosetta 800's conversion juju made the snare in an Afro-pop mix jump out with increased transient snap. Upon closer listening, I was shocked to hear that the Rosetta 800 brought bigger midrange tone and higher definition to this drum, as though a high-end mic preamp had suddenly been slipped into the signal chain.
When comparing the Rosetta 800 to an Apogee PSX-100 using the same methods (two sets of identical 24-bit tracks in Pro Tools routed to each converter, with output levels carefully matched), I noticed only minute qualitative differences. After repeated listenings, the PSX-100 seemed to deliver slightly crisper highs and better background details, but the two were certainly very close in overall character.
Although its list price puts it solidly in the pro category, the Rosetta 800 offers significant two-for-one value with its ability to perform independent dual-stage conversion. And for studio owners like me who may be juggling Pro Tools sessions, 8-channel MDMs, mixed-format transfers, and remote recordings, the Rosetta 800 is one of those versatile and invaluable Swiss Army-knife studio tools.
When it comes to sound, the dramatic impact of the Rosetta 800's converters are not merely a subtle exercise for pros, audiophiles, and tweakers. Assuming that A/D/A conversion is an important aspect of your studio setup, the Rosetta 800 delivers the kind of readily audible difference that is clearly worth the investment. And if there were a Less Is More award for user interfaces, Apogee would get my vote for making the powerful Rosetta 800 smart, simple, and very user-friendly.
Myles Boisen owns and operates Guerrilla Recording and The Headless Buddha Mastering Lab in Oakland, California.
APOGEE ELECTRONICS Rosetta 800
8-channel A/D/A converter $2,995
192 kHz version $3,995
OVERALL RATING (1 THROUGH 5): 4
PROS: Independent A/D/A conversion at high bit rate and high sampling rates. Performs format transfers between ADAT optical, AES/EBU, and analog. Low-jitter clocking. UV22HR dithering for 16-bit output. Soft Limit analog limiting. Word-clock I/O. Easy-to-use control layout with metering. Front-panel AC power switch.
CONS: Professional price. Does not support 2-channel S/PDIF optical.
ROSETTA 800 SPECIFICATIONS
Analog Inputs (8) DSub Analog Outputs (8) DSub Digital Inputs (8) AES, (8) ADAT, (8) on optional card Digital Outputs (8) AES, (8) ADAT, (8) on optional card Word-Clock Ports In, Out Resolution 24 bits Sampling Rates 44.1, 48, 88.2, 96 kHz (±10%);
176.4 and 192 kHz (optional) Frequency Response 10 Hz-20 kHz (± 0.2 dB) @ 44.1 kHz THD+N -105 dB (A/D), -103 dB (D/A) Dynamic Range 114 dB A-weighted (A/D + D/A) Dimensions 1U × 11.75" (D) Weight 15 lbs.