Chapter 2: What Is A Gate?
Typical creative uses
The human ear is connected to an extremely sophisticated organ for processing incoming audio information — the brain. Even in situations where there are many sound sources, we seem to be able to tune in to the sounds we want to hear and reject others. This is sometimes known as the cocktail party effect, where it is possible to pick out one person’s voice — even at a distance — from may conflicting conversations.
The microphone (mic) is less selective in its pick up, being sensitive to all sounds within its range and coverage angle. For example, a mic set to pick up the snare drum of a drum kit will pick up every other drum and cymbal to some extent, and probably the bass guitarist as well. When several mics are positioned on the kit, each one giving a good sound on its own particular drum, but they will all pick up unwanted instruments as well, making the sound less clear.
One solution is to use a noise gate on each mic (see diagram below). The gate will reduce the output from the mic to almost zero when the drum is silent, yet will open practically instantaneously when the drum is played. As the sound from the drum decays, the gate will close again and reject noise from the rest of the kit.
Signal level
Threshold level
Background noise
Output signal
Snare |
| (attenuation | depth) |
| Range |
| |
| Signal without gating |
| |
|
|
|
Signal with gating |
Time |
Gate closed
Open | Gate closed | Open | Gate closed |
The threshold level represents the sound level at which the gate will open. Any sound exceeding the threshold triggers the gate. Sounds at lower levels leave the gate closed and the mic will be almost completely silent.
| DN530 |
6 | Operator Manual |
