What does a compressor do? A compressor, sometimes called a diaphragm, is an electronic device that is used to change the pressure or airflow of a medium (pressure or airflow) by increasing or decreasing the amount of it that passes through. Compressors are used in a variety of situations, but their main use is to increase the air flow through a system or to decrease the amount of air pressure in a system. For example, if you were going to construct a tent, you would not use an inflator to inflate it, you would use a compressor to change the pressure in it.
There are four main parts to a compressor: the compressor motor, the compressor tank, the compressor choke, and the control system. The compressor motor is the most important of these, as it controls how the compressor works. The motor is often called a 'side-chain' because the energy that it expels has to start from somewhere. In our discussion, the motor is called the 'side-chain', since it usually has a sealed combustion chamber where the fuel is burned - like a car exhaust.
The tank is the place where the compressed gas goes into before it becomes pressurized again. Typically, there is a small hole in the bottom of the tank, and this is called the 'threshold'. If the pressure is high, or the volume is small, the gas will come out of the hole at a lower pressure than the threshold. If the pressure is low, or the volume is large, the gas comes out of the hole at a higher pressure than the threshold, forcing its way out of the tank into the compressed chamber.
The compressor's choke is what controls the volume levels that the system can handle. Most compressors have a range of available settings, which can be increased or decreased to achieve certain volume levels. The most common use for these volume levels is to control the fan speeds that are used in air conditioning systems. Many compressors have been designed so that they can be set for very low fan speed settings, for very low ambient temperature conditions, and for very specific amounts of airflow.
There are really only two different major functions that you will want to perform with a compression unit. The first is to control the air flow through the system. This is called the inflation setting, and it is typically best to leave this as the default, unless you are going to change it very frequently. Many compressors will automatically inflate to the right level on their own; however if you are frequently changing air settings, it might be better to leave the inflation setting as default, and then increase or decrease it as needed.
The second function of the compressor is to regulate the flow of air through the system. This is commonly known as the air-flow release (AFR) setting, and this is usually controlled by the pressure of the air being compressed. Often, a smaller, less powerful compressor will not need to have an AFR setting, because the air will be able to get through the system without any additional effort. However, larger compressors can have higher air-flow rates, and these have to have some way to determine an appropriate AFR level. Many compressors will use a signal processor to do this, and there are a number of different processors available, from digital to analog.
One of the most important functions of a compressor is to change the level of compression. Compressors vary in the level of compression that they can perform, and they do this by varying the speed of the rotors in the motor. Speed controls the overall sound level of the compressed signal and is typically best left as a manual setting, unless you are going to use a signal processor in order to better control the compression.
The final major function that a compressor performs is to set the threshold of the signal that it compresses. A threshold controls what gets compressed - in other words, what doesn't get compressed. Most compressors have a threshold parameter, which allows you to define a volume level at which the compressor starts to compress the sound. This helps prevent "crossover distortion," which occurs when two sounds that are compressed by the same compressor start to sound different when compressed together. By allowing a threshold control, you can avoid crossover distortion and get cleaner, more uniform sound.
