Mackie has refined its preamp technology for each successive generation of mixers that it's produced. True to form, the preamps found in its new Onyx series of mixers have supplanted the well-respected VLZs as the preamps of choice in Mackie products. According to Mackie, the Onyx preamps are designed specifically for transparent tracking to a DAW, a PDS, or an HDR system.
FIG. 1: The Mackie Onyx 800R is a fully featured and transparent-sounding 8-channel mic pre and A/D converter.
Considering its confidence in the Onyx preamps, it's not surprising that Mackie has put eight of them — along with 24-bit, 192 kHz A/D converters — into the Onyx 800R, a unit designed as a front end for a digital recording system.
Mother Lode of Options
Like other Mackie products, the Onyx 800R has an amazing amount of connectivity and features. You get eight channels of Onyx microphone preamps that offer a gain range of 60 dB (-20 dBu to 40 dB for the balanced line-level inputs, or 0 dB to 60 dB for the XLR inputs). You can access those preamps through the eight XLR inputs on the rear of the 800R. Channels 7 and 8 have a high-impedance instrument input for direct recording.
Unlike some competing units, there are no line-level ¼-inch input jacks on the 800R. The inputs are instead on a DB25 (25-pin) connector on the rear panel, into which you can plug a breakout cable (not provided). Two other DB25 ports are included: one for analog line outputs and the other for AES/EBU or S/PDIF output.
All eight channels are not identical, but they do share a number of features. Each has a large metal knob that gives you continuous adjustment of preamp gain (see Fig. 1). The individual channels can also be switched between the mic- and line-level inputs. A phase button allows users to reverse the polarity of the signal. A low-cut switch activates an 18 dB/octave highpass filter that cuts off frequencies below 75 Hz.
Each channel is equipped with a phantom-power button that, when pressed, activates a green LED status light. Finally, three LEDs run across the top of every channel to indicate signal-strength levels of -20 dBu, 0 dB, and overload. I wish Mackie had provided a more extensive metering setup; even the narrowest channels look as though they could have accommodated six LEDs across.
Channeling the Onyx
Channels 1 and 2 have a couple of features rarely found in multichannel mic preamps in this price range. The 800R has a built-in M-S (middle-side) decoder. M-S recording is a stereo-miking technique that uses one mic with a cardioid pattern and another with a figure-8 pattern to capture a 3-D stereo field (see the sidebar “M-S Recording and the Onyx 800R”). The 800R uses channel 1 for the cardioid (mid) signal and channel 2 for the figure-8 (side) signal. To facilitate using the 800R with vintage and other high-quality microphones, channels 1 and 2 have a mic-impedance switch with four selections: 300Ω, 500Ω, 1,300Ω, and 2,400Ω.
On channels 7 and 8, you get a ¼-inch, unbalanced, high-impedance instrument input in addition to the XLR mic input. There is also a button to select which input type is active.
Rounding out the front panel is a power button, a sampling-rate select knob for the digital output, and a button for bit depth. The Sample Rate knob lets you choose from seven sampling rates between 32 kHz and 192 kHz or from External sync using BNC word-clock input. Unless you want to use the Onyx 800R as your digital-clock master, you'll need to use the BNC word-clock option. The Bit Depth button selects either 16-bit (with dither) or 24-bit settings. LEDs indicate sampling-rate lock and bit-depth setting.
Lightpipe and More
The rear panel of the 800R houses the unit's input and output connectors (see Fig. 2). To the right of the eight XLR mic inputs is the Mid/Side Decode button and two DB25 connectors for balanced line-level inputs and outputs.
FIG. 2: The rear panel is where you find the XLR mic inputs, the analog line inputs and outputs (on DB25 connectors), and the various digital outputs.
The 800R has two ADAT Lightpipe digital outputs. Both of them output the signal from channels 1 through 8 if the sampling rate is 48 kHz or less. If you select a sampling rate of 88.2 kHz or 96 kHz, channels 1 through 4 are transmitted through the first ADAT output, and channels 5 through 8 are transmitted through the second ADAT output (using the S/MUX II protocol).
If you select a sampling rate of 179.4 kHz or 192 kHz, channels 1 and 2 are transmitted through the first ADAT output, and channels 3 and 4 are transmitted through the second ADAT output (using the S/MUX IV protocol). If you are connecting the 800R to an audio interface through the ADAT outputs, and you're using sampling rates higher than 48 kHz, make sure that your interface is compatible with the S/MUX protocols.
The external word-clock input and a termination button are also located on the 800R's rear panel. If the 800R is the last digital device receiving word clock, make sure to terminate the signal. There are buttons on the DB25 connector for AES/EBU and S/PDIF digital output to select between 110Ω or 75Ω signals, professional AES/EBU or consumer S/PDIF operation, and dual- or single-wire format. Additionally, there is an input for the power cable. The unit automatically adjusts for any VAC between 100V and 240V.
Overall, the unit has a solid feel to it. It's heavy, none of the buttons or knobs feel loose, and the jacks are securely anchored to the chassis. All the channel buttons have their functions silk-screened onto them for easy identification. Other than the minimal metering, the 800R is a superbly designed device.
The real test, of course, is how the Onyx 800R sounds. My initial impression was that its preamps sounded full bodied, transparent, and noise free, even at the highest levels of gain. They sounded as though they had been designed to avoid coloring the signal, rather than sounding like “character” preamps. The highpass filter seemed very effective, limiting the low-end rumble of the source material without otherwise coloring the signal.
I compared the Onyx 800R to the mic preamps of the RME Fireface 800, which are the same preamps from RME's OctaMic D. The OctaMic D has features that are similar to the Onyx 800R; it offers almost identical amounts of gain, and it retails for $200 more.
The preamps of the RME units sound quiet, transparent, and usable in almost every situation except for powering ribbon mics (there's not enough gain). I compared the Onyx and Fireface preamps by recording acoustic guitar, electric guitar, and vocal sources through dynamic, condenser, and ribbon mics. I also compared electric guitar DI signals. I tested the Onyx 800R as word-clock master and as word-clock slave.
The Onyx 800R and the Fireface 800 preamps were almost identical — so much so that I used Apple Logic Pro's Match EQ to learn the EQ footprint of each for comparison. The results were almost completely flat across all the sources and instruments tested.
Like the RME units, the preamps in the Onyx 800R did not provide enough gain for a ribbon mic that was close-miking an acoustic source. Adjusting the Onyx 800R's mic impedance switch helped to match the unit to the source mic, but not quite enough for that application. To its credit, however, even at maximum gain, the 800R was still silent. The Onyx 800R sounded the same to me when it was used as a word-clock master as it did when used as a word-clock slave.
Gem of a Unit
Overall, I was impressed with the Onyx 800R. It has eight full-bodied, usable, and transparent preamps, and a host of very desirable features at a great value (less than $160 per channel). It also easily integrates into any recording setup.
The 800R comes with an excellent printed manual, which is a rare thing these days. Anyone looking for a well-featured front end for a DAW system or other multi-track should give this unit serious consideration.
Orren Merton is the author of Logic Pro 7 Power! (Muska & Lipman, 2004) and Logic 7 Ignite! (Muska & Lipman, 2005).
ONYX 800R SPECIFICATIONS
Analog Inputs (8) balanced XLR mics, (2) ¼" TRS high-impedance instruments, (8) balanced line-level inputs (on DB25 connector) Analog Outputs (8) balanced line-level outputs
(on DB25 connector) Digital Outputs (8) channels ADAT, S/MUX II/IV on Toslink optical connectors, (8) channels AES/EBU or S/PDIF on a DB25 connector Digital Sync (1) BNC connector for external word-clock input Frequency Response mic input to line output (gain @ unity): +0/-0.1 dB, 20 Hz-30 kHz; mic input to digital output (AES, 192 kHz sampling rate): +0/-0.2 dB, 20 Hz-85 kHz Distortion (THD + N) mic input to line output: < .0007%, 20 Hz-20 kHz, 1 kHz input at +4 dBu, preamp @ unity gain; mic input to digital output (AES, 48 kHz sampling rate): < .004%, 10mV RMS input Dynamic Range mic input to line output: >123 dB; mic input through A/D converters: >113 dB Signal-to-Noise > 103 dB (A-weighted, ref. +4 dBu, mic in to line out, gain @ unity) Crosstalk < -100 dB (@1 kHz, +10 dBu signal on adjacent input) Input Gain mic in: 0 dB-+60 dB
line in: -20 dB-+40 dB Phantom Power +48V Dimensions 19" (W) × 1.75" (H) × 14.4" (D) Weight 10.6 lbs.
M-S RECORDING AND THE 800R
M-S (middle-side) recording is a technique involving stereo recording with coincident-pair microphones. This type of technique uses a pair of closely positioned microphones that are oriented in a specific way in order to capture the true stereo field.
FIG. A: With M-S -miking, a -directional mic is used to pick up the middle of the -stereo image, and a -figure-8 mic is used for the sides.
M-S uses the unidirectional characteristics of a cardioid microphone that is pointed straight at the sound source, and the bidirectional characteristics of a figure-8 microphone that is placed next to the cardioid microphone and perpendicular to the sound source. Combined, these two techniques capture a side-to-side and front-to-back stereo image (see Fig. A).
Since the raw tracks are not standard “right-side/left-side” stereo tracks, the image needs to be decoded using sum-and-difference matrix so that the listener hears a normal stereo image. You can adjust the depth of the stereo field by adjusting the gain of channels 1 and 2. You can then record the output of channels 1 and 2 into a stereo track on your DAW, MDM, or HDR, and you will get a stereo image that will play back normally on any monitor system.
8-channel mic preamp and A/D converter
OVERALL RATING [1 THROUGH 5]: 4
PROS: Good sound. Good value. A wide range of digital connectivity. Variable mic impedance for two of the channels. Individual phantom-power switches for each channel. Two channels with high-impedance instrument inputs. M-S support.
CONS: Limited metering. Not enough gain for ribbon mics. Must purchase third-party breakout cables to access ¼-inch line-level I/O and AES/EBU and S/PDIF digital outputs.