Explanations of the key parameters in a compressor and their functions in a live sound setting:
Friday, January 12, 2024
The following are explanations of the key parameters in a compressor and their functions in a live sound setting:
1. Threshold: The threshold determines the level at which the compressor starts reducing the audio volume. Any signal exceeding this threshold will trigger the compressor to kick in and compress the audio. In live sound, the threshold helps control peaks and ensure that the audio stays within the desired range.
2. Ratio: The ratio determines the amount of gain reduction applied to the audio signal once it exceeds the threshold. For example, a 4:1 ratio means that for every 4dB, the input signal goes above the threshold, and the compressor will only allow 1dB to pass through. An appropriate ratio setting in live sound helps control dynamic range and maintain a consistent audio level.
3. Attack: The attack time specifies how quickly the compressor responds to an audio signal that exceeds the threshold. It determines how long it takes for the compressor to start applying gain reduction after the threshold is surpassed. In a live sound scenario, a fast attack time can be useful to catch sudden transients and control peaks effectively.
4. Release: The release time determines how quickly the compressor stops applying gain reduction after the audio level falls back below the threshold. It defines how long it takes for the compressor to return to normal operation. In live sound, the release time is important to ensure a smooth transition back to uncompressed audio and to avoid unnatural pumping or breathing effects.
5. Knee: The knee determines the shape of the compression curve near the threshold point. A "hard knee" setting results in an immediate transition from uncompressed to compressed audio, while a "soft knee" setting creates a more gradual and subtle compression onset. In live sound, a soft knee setting is commonly used to achieve smoother compression and avoid abrupt changes in audio dynamics.
By adjusting these parameters appropriately, live sound engineers can effectively control the audio levels, smooth out dynamic variations, and maintain a consistent volume throughout a performance or event.