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Calrec Audio RQ Series Processors - ProSoundNetwork.com

Calrec Audio RQ Series Processors

Calrec's success in the console market led the company into the modular market with the RQ Series, which is a line of four high-performance, single-rack-space audio units. The series includes a twin stereo compressor/limiter, a twin stereo equalizer, a quad stereo mic/line preamplifier and a mono recording channel with a mic/line preamplifier, a parametric equalizer, a compressor and an expander/gate.
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Calrec Audio is one of the oldest audio manufacturers in operation today. Established in the late 1950s by a group of hi-fi enthusiasts,the company originally built amplifiers and loudspeakers. The group soon progressed to tape machines and microphones to record their own material, and so was born the Calder Valley Sound Recording Group, later shortened to Calder Recordings. Calder Recordings produced and marketed the CALREC range of microphones, and in 1970the company name was changed to Calrec Audio Ltd.
Product PointsApplications: Studio recording; 5.1 surround; television and film sound

Key Features: RQD 6400: true quad or stereo operation with side chains; RQP 4400: handles up to four stereo pairs of mics; switchable for MS conversion; RQQ 2200: 2-channel, 4-band EQ with 2-band filters; RQP 3200: one-channel preamp, EQ, compressor/expander/gate

Price: RQD 6400 - $2,785; RQP 4400 - $3,360, RQQ 2200 - $2,360; RQP 3200 - $2,899

Contact: Calrec 207-773-2424

Plus

+ Fantastic sound

+ Solid construction

+ Compact

+ Flexible

Minus

- Expensive

The Score; As well as meeting the needs of the pro studio and engineer, Calrec's RQ series provides some powerful tools for professionals working with extensive stereo material.
Today Calrec, located in West Yorkshire, England, has a staff of 100 employees. Though a staple in the broadcast industry, Calrec is not as familiar a name in the project and commercial recording studio

Calrec's success in the console market led the company into the modular market with the RQ Series, which is a line of four high-performance, single-rack-space audio units. The series includes a twin stereo compressor/limiter, a twin stereo equalizer, a quad stereo mic/line preamplifier and a mono recording channel with a mic/line preamplifier, a parametric equalizer, a compressor and an expander/gate.

Features - the RQD 6400

The RQD 6400 Twin Stereo Compressor/Limiter is two independent stereo compressor/limiters. The rear panel features four female XLR connectors for audio input (Channel 1 left, Channel 1 right, Channel 2 left and Channel 2 right) and four male XLR connectors for audio output (Channel 1 left, Channel 1 right, Channel 2 left and Channel 2 right). There are also two female XLR connectors for voiceover (side chain) inputs, one for each stereo channel.

The front panel of the RQP 6400 has identical controls for both stereo channels. The compressor has a variable ratio from 1.5:1 to 10:1 and a threshold adjustable from +10 to ö20. Attack time is selected by a switch as either fast or normal. Attack time varies with the ratio; if the ratio is 5:1, attack time is approximately 4 ms on the normal setting and 0.2 ms on the fast setting.

Recovery time is adjustable between 0.1 and 4 seconds. When in auto recovery mode, recovery is in two phases - a fast recovery of about 0.1 second followed by a slow recovery of about 1.5 seconds.

Pressing the VO switch introduces voice-over (sidechain) control. The voiceover gain control lets the user adjust the input from -70 dB (for mic input) to +10 dB (for line input). A 10 dB input above the setting yields approximately 20 dB gain reduction.

The limiter-on switch inserts the limiter into the circuit. The limiter threshold can be adjusted from -4 dBu to +16 dBu. Limiter recovery can be adjusted from 75 ms to 1 second. If the recovery is placed in auto mode, the recovery is in two phases, a fast recovery of about 0.1 second followed by a slow recovery of about 1.5 seconds. The limiter is also equipped with a peak limit LED that illuminates if the program level exceeds the level set on the limiter threshold control when the limiter is switched on.

Two LED meters (one for each channel) show up to 24 dB of gain reduction. The meters are engineered to give finer resolution at lower levels. Limiter performance is included in the channel's metering.

Controls for both the compressor and the limiter sections are identical for both stereo channels of the RQD 6400. The only other controls are the power switch located on the front panel and the link button that joins the two stereo compressor and limiter sidechains together to form a quad unit.

The ability to perform extremely high-quality compression and limiting in quad makes the RQD 6400 a powerful tool for both film and television work. This is the only truly fantastic sounding quad compressor that I have encountered.

The RQP 4400

The RQP 4400 is a quad stereo mic/line preamplifier - it can handle four stereo pairs of microphones. The rear panel features four female 5-pin Cannon connectors for audio input and four male 5-pin Cannon connectors for audio output. The unit I tested included short adapter cables that convert two male XLR connectors into a female 5-pin connector and cables that convert two female XLR connectors into a male 5-pin connector.

The front panel of the RQP 4400 has four identical sections, one for each stereo preamplifier. Each section contains a gain control, which varies the sensitivity from ö72 dB to +12 dB in 6 dB increments. Gain is also adjustable by a +/-3 dB trim control. The balance control allows the user to fine-tune the balance between the two microphones in the stereo pair up to +/-3 dB.

Each channel is equipped with a switch for M/S conversion and an LED indicator to inform the user of the circuit's status. The phase reverse switch on each channel lets the user invert the phase of the left and/or right input. Each channel's phantom power switch turns on 48 V phantom power for that preamp. Each channel is also equipped with switches to insert 18 dB/octave high-pass filters at three frequencies (47 Hz, 82 Hz or 150 Hz).

With a frequency response of 20 Hz to 20 kHz +/-0.5 dB the RQP is amazingly accurate. The unit's maximum output level is +27.5 dBu with a 10-kohm load or +23.5 dBu with a 600-ohm load. The overload LED glows 4 dB before clipping, providing an early warning for signal clipping.

The RQQ 2200

The RQQ 2200 Twin Mono Equalizer and Filter has two independent balanced mono line I/O channels, each with a four-band equalizer and two-band filters. The rear panel of the RQQ 2200 is equipped with two female XLR connectors for signal input and two male XLR connectors for signal output.

The front panel of the RQQ 2200 has identical controls for both mono channels. The two parametric middle bands of the equalizer can be switched from normal bell (Q1.0) to high bell (Q3.5) and the two parametric outer bands can be switched from normal shelf to bell (Q1.0).

All four bands have gain of +/-16 dB at the selected frequency. The sweepable high-pass filter has an 18 dB/octave slope and the sweepable low-pass filter has a 12 dB/octave slope. The RQQ 2200 has a maximum input level of +28 dBu and distortion measures less than 0.005% (20 Hz to 10 kHz) at +20 dBu.

I've been a faithful user of the GML stereo equalizer for more than 10 years now and I rarely encounter an equalizer I believe is sonically comparable. The RQQ 2200 is one of the rare exceptions. I'm especially fond of the sound of the filters. I found both the low-pass and the high-pass filters very musical and I made frequent use of both filters when using the RQQ 2200.

The RQP 3200

The RQP 3200 preamplifier, EQ, compressor/expander/gate is a high-quality self-contained audio signal path. The rear panel includes two female XLR connectors for audio input. One connector accepts microphone level input and the other accepts line level input. There is a female XLR for key input. This input connects external key input to the side chain and feeds the gate only when gate is selected.

The rear panel includes three male XLR connectors. The first provides balanced audio output. The second provides a link function allowing two RQP 3200s to be linked together. The third, labeled external switch, lets the equalizer and/or the filter circuits switch on and off from a remote position.

The front panel of the RQP 3200 is divided into four sections - the preamplifier, the equalizer, the expander/gate and the compressor. The first section is the preamplifier section. The preamplifier can be varied from -72 dBu to +12 dBu in 6 dB increments. There is a fine gain control that adjusts the mic gain +/-5 dB or the line gain +/-15 dB.

The preamp is equipped with an overload LED that lights 4 dB before clipping. This section is equipped with three switches. The first selects between line and microphone input, the second reverses the phase of the signal, and the third activates phantom power.

The equalizer section on the RQP 3200 is identical to the equalizer on the RQQ 2200 with the exception of the two added dynamics buttons. Selecting the dynamics switch in the filter section together with the filter in switch puts the filters in the audio path of the dynamics side chain. Selecting the dynamics switch in the equalizer section together with the EQ-in switch puts the equalizer in the audio path of the dynamics side chain.

The expander/gate section includes a switch to select normal (4 ms) or fast (0.2 ms) attack time. Recovery time is variable from 75 ms to 4 seconds. The ratio of the expander below the threshold is normally a variable curve to yield a subtle effect in the audio signal. If selected, the ratio switch will set this ratio at 2:1.

The compressor has a variable ratio from 1:1 to 50:1. Attack time can be switched between normal (4 ms) and fast (0.2 ms). The recovery time is variable from 75 ms to 4 seconds. When the auto button is pressed, recovery is in two phases, a fast recovery of about 0.1 second followed by a slow recovery of about 1.5 seconds.

The compressor section includes a switch to move the compression circuit from the normal post-equalizer position to pre-equalizer. The link switch links the side chains of the RQP 3200 with one or more similar units. When using the compressor there is a loss of overall gain. This loss is made up by the level control.

The unit is equipped with an LED meter that shows separately the gain reduction due to compression and that due to expansion or gating. If the dynamics are by-passed, the meter will continue to operate (at reduced intensity) as a preview of what it would be doing if it were on.

Inuse

I spent nearly two months using the RQ series on a day-to-day basis and always ended up with quality tracks. All four of the Calrec RQ pieces worked remarkably well and I was always able to effectively adapt them to my current recording situation. I used them at every stage of the recording process, for tracking, overdubbing and mixing. The RQP 4400 also performs flawlessly as a quad mono preamp, and the RQD 6400 works as a twin mono compressor/ limiter. My opinion is that both units are too expensive to purchase without making at least occasional use of their stereo signal paths.

Calrec's RQ series is made up of extremely high-quality and fantastic-sounding units, but they are on the costly side and possibly beyond the reach of many project studios. (The price of these units dropped considerably just prior to press time: The RQD 6400 lists for $2,785, the RQP 4400 lists for $3,360, the RQQ 2200 lists for $2,360 and the RQP 3200 lists for $2,899-Ed.)

Summary

The units are designed remarkably well. The engineering team obviously did their homework. Each of the four units includes a ground pin on the rear panel to simplify grounding. The units each accept a standard power cable through a special power jack that incorporates a wire clip that securely holds the cable in place. Gone are the days of power cables falling out in transport.

With 5.1 being the buzzword for the new millennium, the RQD 6400 compressor/limiter and the RQQ 2200 equalizer should rapidly find their way into a number of studios trying to make their equipment list surround sound-friendly. For studios involved in large amounts of stereo and M/S recording or television and film work, the RQP 4400 preamplifier should easily find a home. For the professional or project studio that needs an additional high-quality, self-contained signal path, the RQP 3200 preamplifier/EQ/compressor/expander/gate should be a major consideration.