Audio meters help sound engineers and producers to gauge the output level of their audio signal. They will aid you in the process of taming fluctuations in the dynamic range of your track and enable you to avoid any spikes in volume that could lead to digital clipping.
Meters used in DAWS and other forms of digital audio equipment measure the signal levels in a decibel system where the signal is measured from 0dB downwards. 0dB is the highest point that a digital audio system can handle before it leads to clipping. Unlike the balmy, saturation obtained from clipping analog systems; the distortion caused by digital clipping is quite unpleasant. Meters will guide you in keeping your audio at a constant level below that 0dB ceiling. There are two types of digital audio meters that can assist you in this process.
Digital Peak Program Meters or ‘PPM’ react swiftly to an audio signal to display its maximum level. They respond instantly to the changes in level of a piece of audio giving you an instantaneous update of where your track sits on the decibel system. This makes PPMs incredibly useful in alerting you to when there is a sudden spike in gain which can lead to digital clipping.
RMS stands for ‘Root Mean Square’. The mechanism of this type of metering is based around taking the average of the output of a piece of audio over a given period of time. This means that, rather than displaying sudden changes in the gain of your track, they will give you an impression of the general loudness of a mix. RMS meters are useful for keeping an eye on shifts in the dynamic range of your track and keeping general volume at a similar level.
It’s ideal to use a combination of both PPM and RMS metering. Use your peak meter to measure where there are any sudden spikes in volume that may lead to digital clipping. Follow this by using the RMS meter to measure the overall volume of your track, keeping an eye on the dynamic range. Even with metering however, always remember that your ears are your most important tool. They will always give the better measurement of audio fidelity.