User manual SOUNDCRAFT GB8

[. . . ] GB8 User Guide GB8 User Guide 1 IMPORTANT Please read this manual carefully before using your mixer for the first time. © Harman International Industries Ltd. 2004 All rights reserved Parts of the design of this product may be protected by worldwide patents. ZM0308-03 Soundcraft is a trading division of Harman International Industries Ltd. Information in this manual is subject to change without notice and does not represent a commitment on the part of the vendor. [. . . ] This will present a short circuit at RF frequencies, thus lowering the effective shield impedance to ground. However, at low audio frequencies the reactance of the capacitor will be sufficiently high not to cause an earth loop problem. 14 GB8 User Guide Points to Remember In all cases, use good quality twin screened audio cable. Always connect both conductors at both ends, and ensure that the screen is only connected at one end. This is needed to provide both safety and screen returns to the system star point. Equipment which has balanced inputs and outputs may need to be electrically isolated from the equipment rack and/or other equipment, to avoid earth loops. It is important to remember that all equipment which is connected to the mains is a potential source of hum and interference and may radiate both electrostatic or electromagnetic radiation. In addition, the mains will also act as a carrier for many forms of RF interference generated by electric motors, air-conditioning units, thyristor light dimmers etc. Unless the earth system is clean, all attempts to improve hum noise levels will be futile. In extreme cases there will be no alternative but to provide a completely separate and independent `technical earth' to replace the incoming 'noisy earth'. However, always consult your local electricity supply authority to ensure that safety regulations are not being infringed. WORKING SAFELY WITH SOUND Although your new console will not make any noise until you feed it signals, it has the capability to produce sounds which when monitored through an amplifier or headphones can damage hearing over time. The table below is taken from the Occupational Safety & Health Administration directive on Occupational noise exposure (1926. 52): PERMISSIBLE NOISE EXPOSURE DURATION PER DAY, HOURS 8 6 4 3 2 1. 5 1 0. 5 <0. 25 SOUND LEVEL dBA SLOW RESPONSE 90 92 95 97 100 102 105 110 115 Conforming to this directive will minimise the risk of hearing damage caused by long listening periods. A simple rule to follow is the longer you listen the lower the average volume should be. Please take care when working with your audio - if you are manipulating controls which you don't understand (which we all do when we are learning), make sure your monitors are turned down. Remember that your ears are the most important tool of your trade, look after them, and they will look after you. Most importantly - don't be afraid to experiment to find out how each parameter affects the sound - this will extend your creativity and help you to get the best results. Recommended Headphone Impedance 200-600 ohms. GB8 User Guide 15 Setting Up & Troubleshooting Initial set-up Once you have connected up your system (see the sections on connection and wiring earlier in this manual for guidance) you are ready to set initial positions for the controls on your mixer. Set up individual input channel as follows: l l l l Connect your sources (microphone, keyboard etc. ) to the required inputs and release the MUTE switches. Note: Phantom powered mics should be connected before the 48V is switched on. Set Master faders at 0, input faders at 0, route the channels to MIX and set power amplifier level to suit the application. Press the L-R switch in the MONITOR SOURCE part of the master section. Provide a typical performance level signal and press the PFL button on the first channel, monitoring the level on the bargraph meters. Adjust the input gain until the meter display is in the amber section, with occasional peaks to the first red LED at a typical maximum source level. This allows sufficient headroom to accommodate peaks and establishes the maximum level for normal operation (but see note below). [. . . ] Each return pair can be routed either to the main L & R main buses, or to pairs of groups, ie Stereo Return 1 routes to Groups 1 (Left signal) and 2 (Right signal), Stereo Return 2 routes to Groups 3 & 4, etc. This routing is done via the routing switches (15). GB8 User Guide 31 L, R & C Outputs Each of the 3 main mix busses, Left, Right and Centre, has its own insert point. Each mix bus has its own Fader (16) following the insert point in the signal path. The post-fader signal for each bus is then routed to the following places: · its main output XLR on the rear connector panel, · feeds to the matrix 1- 4 buses (17), · the REC/ALT output section, · the MONITOR SOURCE select switches L-R (18) and C (19). [. . . ]