GL2 INTRODUCTION The GL2 continues ALLEN & HEATH’s commitment to provide high quality audio mixing consoles engineered to meet the exacting requirements of today’s audio business. It brings you the latest in high performance technology and offers the reassurance of over two decades of console manufacture and customer support. This user guide presents a quick reference to the function, application and installation of the GL2.
GL2 THE GL2 The ALLEN & HEATH GL2 offers the flexible solution to the many requirements of the live sound and recording environment; whether for conference sound ... in a club ... theatre .. or church ... for touring ... contract hire ... as well as stereo and multitrack recording. The key to this versatility is the unique switching arrangement which configures the console for Front-of-House or On-stage Monitor operation, or a combination of both.
GL2 SPECIFICATION 0 dBu = 0.775 Volts RMS 0 dBV = 1 Volt RMS INTERNAL OPERATING LEVEL: -2 dBu INTERNAL HEADROOM: ............ +23 dB MAX OUTPUTS: .......................... balanced +27 dBu 600 ohms max load unbalanced +21 dBu 2kohms max load All console inputs and outputs are in-phase except for the GROUP INSERTS METERS: ..................................... Peak responding bargraph 0VU = +4dBu at XLR outputs PEAK LEDs: ................................. Turn on 5dB before clipping SIG LEDs: .............
GL2 INSTALLING THE CONSOLE The GL2 fits into an 11U space in a standard 19" rack system. Alternatively the console may be adapted for plinth or table top operation. 19" rack width Provide adequate space behind the rear of the console power unit for ventilation. The panel may feel warm around the power unit. This is quite normal as the chassis acts as a heatsink for the internal power supply components. The two M3 base securing bolts each side align with mounting recesses in the rack system.
GL2 INTERCONNECTIONS Where possible use balanced connections for the channel INPUTs and GROUP, L-R and MONO outputs to minimise noise pick-up. Avoid running audio cables near to mains or lighting cables or thyristor dimmer units, power supplies etc. These may cause audible hum and buzz. The use of low impedance sources significantly reduces interference pick-up. Check the cables for correct wiring to avoid problems with phase reversal and unreliable connection.
GL2 INPUT MATCHING THE INPUT PRECAUTION ! ALWAYS MAKE SURE THAT +48V SWITCHES ARE OFF (UP POSITION) WHEN THE CHANNEL INPUT XLRS ARE CONNECTED TO NON-PHANTOM POWERED OR LINE SOURCES. A wide-ranging padless input pre-amplifier matches the connected audio source to the console. Use the PFL system to set GAIN for the correct internal operating level (0dB on the meters). Centre position provides +10dB line gain. MIC/LINE selects a balanced mic or line XLR source.
GL2 STEREO MATCHING THE INPUT For INPUT A set the IN A/B switch up. For INPUT B set the IN A/B switch down. MONO combines the left and right inputs to mono the source, or may be used to input a mono source to the stereo channel path. The GAIN control allows a wide range of equipment to be correctly matched to the console. 4-BAND EQUALISER Shelving HF and LF and two fixed frequency peak/dip mid controls provide 14dB of cut and boost. EQ IN switches the equaliser in or out of the channel path.
GL2 GROUP OPERATING MODE The recessed GRP/AUX REV switch determines the way in which the group signal path is arranged. For conventional operation FRONT-OF-HOUSE or RECORDING (switch up) the group mix is routed to the main signal path through the insert, FADER and MUTE switch to the balanced XLR output, while providing subgrouping, AFL monitoring, signal and PEAK metering.
GL2 MASTER MONITORING THE SYSTEM The PHONES/MONITOR section allows the engineer to listen to L-R (aux 5-6) either PRE or POST the master faders, or 2-TRACK return through up to two pairs of stereo headphones or monitor speaker systems while displaying the selected source on the L and R monitor meters. The peak responding LED bargraph meters are positioned above each group strip.
GL2 MONO FRONT-OF-HOUSE conference ... club ... disco ... live shows ... theatre ... church ... touring ... RIGHT LEFT 3 4 1 2 5 FOLDBACK 6 pre-fade aux sends 1 EFFECTS 2 groups 3 4 insert sends returns COMPRESSOR/LIMITERS These are often used to prevent excessive peaks overloading the amplification system, for example in club installations subject to sound level control. This example shows the 4 groups, L, R, and Mono outputs feeding a 7 stack FOH amplification system.
GL2 ON-STAGE MONITOR On-stage mixing system for local control of performers monitor loudspeakers (wedges) With dedicated output for the stage engineers wedge loudspeaker. STAGE MONITORS 1 6 5 2 3 mic splitter 4 AMPLIFIERS ENGINEERS WEDGE MONITOR Set up the WEDGE MIX by selecting one or a combination of the group/L/R AFL (monitor 1 to 6) switches to listen to the desired stage monitor outputs. These are post insert (post graphic EQ) and post output fader for accurate monitoring.
GL2 MONO MULTIMODE L-M-R Front-of-House system with 4 dedicated stage monitor sends. RIGHT LEFT 3 4 STAGE MONITOR 2 1 STAGE MONITOR EFFECTS groups (aux 1-4) aux 5, 6 insert return 1, 2 EQUALISERS inserts COMPRESSOR/LIMITERS Signal processors such as these are useful to prevent excessive peaks overloading the amplification system. To tune out stage resonances to prevent acoustic feedback. These may alternatively be positioned on stage in series with the amplifier feeds for performer control.
GL2 RECORDING stereo amplifier stereo and multitrack ... studio ... live ... location ... audio visual ... production ...