[. . . ] The Gradav Microphone Guide Selecting a microphone for a particular task can be difficult. We have prepared this guide as an introduction to microphones currently available for Hire from us, with suggestions for use. [. . . ] The pre-amplifier can be powered by an internal battery and/or a `phantom' feed. Most modern microphones are designed to operate with an impedance around 200 ohms. A balanced signal still needs an overall screen, but the signal is carried on 2 conductors working together in a push/pull arrangement. The induced noise signals are equal but completely out of phase, and so they cancel. To unbalance a balanced signal link the `out of phase' (cold) signal to the screen. Pickup Patterns Most of the microphones we use are more sensitive in some directions than others. Select a microphone whose directional characteristics best suit the task in hand. Although discussed in 2 dimensions, you will need to remember that pickup patterns are 3 dimensional. Below are listed the most popular pickup patterns we supply. CARDIOID SUPER CARDIOID (SHORT) SHOTGUN OMNI Good rear rejection with a wide frontal pickup. This has a better rear rejection and a narrower frontal pickup with a `reach' that is longer than the standard cardioid. Beware of the significant rear sensitivity when placing near loud sources. We meet this pattern only with `tie clip' microphones used with radio microphone belt packs. What is a good vocal microphone? [. . . ] Flown over the stage, these microphones need to be sensitive enough to pickup well at a distance, but not so directional that `hot' and `cold' spots appear. The capacitor Short Shotgun fills this role well. Gradav Hire & Sales Ltd Unit C6 Hastingwood Trading Estate Harbet Road, London N18 3HU Phone 020 8803 7400 FAX 020 8803 5060 email office@gradav. co. uk [. . . ]