The entry models in the Sonifex Reference Monitor range, these 1U rack-mounting audio monitors, with both loudspeakers and meters, use a similar speaker system to the premium designs, to offer a good sound with a reduced feature-set. They range from a two-input analogue model to a design with two analogue and six digital inputs. All have LED-bar-graph meters and a line-level, balanced, analogue output fed from the source selector.
Both models are built in welded, sealed, stainless-steel cases, with milled, anodised aluminium front panels. Measures to avoid compromise to the acoustic output include foam seals for the lid, foam sealant on XLR and USB connectors and silicon sealant applied to components to avoid movement or vibration.
The loudspeaker system is three-way. The two drivers for left and right mid and high frequencies are mounted in moulded enclosures. The forward-facing bass unit is fed with a mono signal from the DSP based active crossover. The drivers are magnetically shielded to avoid interference to CRT and TFT displays.
The front panel is dominated by speaker grilles at either side. These have separate apertures for the MF/HF drivers and the internal LF unit. The source to be monitored is chosen with a push-button switch, with LED indication of the current source. The level of the chosen source is shown on an eight-segment LED bar-graph display with PPM and VU scales indicated. The bar-graph can optionally be lowered by 10dB (if using the unbalanced input), set by a switch on the rear. A single phase-meter LED indicates channel correlation or phase error conditions. There are rotary balance and volume controls (see below), which feed a speaker protection limiter, headphone output, the crossover, power amplifiers and the speakers. Inserting a jack into the 6.35mm headphone socket causes the speakers to mute. LEDs indicate if the loudspeaker limiter is activated.
A switch on the rear allows the unit to monitor either stereo signals, with the two control knobs on the front panel acting as stereo volume and balance control to alter the stereo imaging of the left and right channels, or dual-mono signals, with the two control knobs acting as left and right volume controls. A pair of line-level analogue audio outputs follow the selected source at the selected level, or optionally at 10dB lower (if using the unbalanced input), again set by a switch on the rear. Settings on the front panel are stored in non-volatile memory which is recalled at power-up. The audio level meters may be set to either PPM or VU characteristics, again by a switch on the rear.
The rear panels have an IEC power inlet with associated fuse, as well as the audio inputs and outputs. All models have a pair of XLR outlets for the analogue line-level outputs of the source monitored. Analogue stereo inputs one and two each have a pair of balanced XLR connectors. These may be wired unbalanced if required. Input two has, in addition, a pair of RCA(phono) sockets. A miniature switch bank provides the meter level, meter characteristic, level-control mode and output level setting as described above.
Inputs: +18dBu, at 0dB gain, 20kohms, analogue XLR, 10k ohms, analogue RCA(phono), maximum; 0dBFS, 110 ohms, 32-192kHz sampling rate, digital, maximum. Common mode rejection: 60dB typical. Input gain: +10dB on unbalanced inputs. Response: 20Hz-20kHz +0/-0.5dB. Distortion: Better than 0.02%, 1kHz, +8dBu output. Noise: -95dB RMS, 0dB gain, below +8dBu output. Crosstalk: Better than -90dB / -85dB, 1kHz/10kHz, at 0dBu. Outputs: +18dBu, 50 ohms. Crossover: 250Hz. Power amplifiers: 2x 7W, 1x 15W. Distortion: Better than 0.1%, at 1kHz, 3W, HF; Better than 0.01%, 100Hz, 6W, LF. Noise: Better than -102dB referred to full output. Headphone output: 80mW, 32 - 600 ohms load. Acoustic output: 98dB SPL, peak, at 610mm. Power source: 85-264V AC, 47-63Hz, 60W peak. Dimensions: 480 x 270 x 44 (w x d x h)mm. Weight: 4.4kg.
Included accessories: Manual. AC power cable.
RM-CA2 - Two analogue stereo channels
This has a single push-button to select between the two analogue inputs. Two LEDS are positioned next to two printed blocks on the front panel which may be marked to designate the sources.
RM-CAD8 - Two analogue stereo channels and six digital stereo inputs
This model can select a source from an additional six stereo digital inputs. As well as the two stereo analogue inputs there are also four stereo AES/EBU balanced inputs, one stereo S/PDIF unbalanced input and a stereo optical unbalanced input. Again a single push button is used to cycle through the inputs; this model has eight LEDs with annotation areas. The source-select button illuminates to indicate synchronisation lock to the incoming digital source. The rear has, additionally, four female XLR, one RCA(phono) and one TOSlink connector, for AES/EBU, S/PDIF and optical inputs respectively. Sample-rate converters on the digital inputs allow sources of different sample rates to be connected and monitored, between 32kHz and 96kHz.