Threshold
Overview
The term "threshold" as applied to audio refers to a specific volume level where a process begins to take effect. In some cases the threshold is variable by the user and in other cases it is at a "fixed' level.
Basics
In order to "fit" wide dynamic range audio signals into limited dynamic range recordings; some form of volume level control is necessary.
There are two types of volume control:
- Manual- typically a "volume" or "Gain" control on the recording device or a device which is feeding the inputs of the recording device.
- Automatic- Can be any one or a combination of the following: Compressor, limiter, expander/noise gate, analog soft limiting (or "analog saturation"), digital soft saturation.
In the case of compressor, limiter, expander/noise gate the threshold is typically user-controllable in the form of a "threshold" adjustment or a combination of input and output level controls. Because saturation modes are basically "peak level" controls; their thresholds are "fixed" near peak volume level.
The basic premise is that for signals with a volume level lower than the threshold the signal is unchanged. as the volume level increases and exceeds the threshold, the process begins. In some cases, the process is applied in a linear manner where every increase of the input level by one dB results in the same amount of change to the output signal, and in other cases the process has a more "progressive" non-linear effect where the effect is minimal just above the threshold and increases as the input level increase. The saturation modes of Lavry AD converters are an example of non-linear processes. Another example is the "soft-knee" compressor or limiter.
(Please note: The one exception is in the case of a an expander/noise gate; in which case the signal is unchanged above the threshold and processed below the threshold.)
Lavry Products
- LavryGold AD122-96 MkIII for more information click here
- LavryBlue MAD-824 for more information click here
- LavryBlack AD11 for more information click here