Can we apply further processing after the limiter?
Strictly speaking, there should never be any plugins inserted after a limiter unless it’s for dithering purposes (dithering is a process that helps the smooth conversion from higher word lengths to lower when bouncing a project down; 24-bit to 16-bit for instance). There is however one situation where a certain kind of technique can be applied after the limiter – when you plan to get the final result really loud but that’s all to come in the advanced Part 2. For now it’s best to always think of your limiter as the last process in the chain. Here’s why:
Let’s say you applied an EQ after the limiter. If you boosted any frequency bands, you will surely hit the top and trigger the red lights indicating you are clipping the audio (clipping off the tips of the waveforms). This is because the limiter has already pushed everything up to just before hitting the top. Doing so will probably produce audible distortion at the output. And if you reduce a band of frequencies, you will loose some of the loudness you just obtained by using the limiter in the first place.
If the EQ was to go before the limiter, there would be no risk of clipping when boosting a frequency band. Reducing a band’s gain, which would lower the RMS level, could be replenished by pushing the limiter a little harder. For best results, put the limiter last in the chain. Try to think of a limiter as a final seal that cannot be broken.
Important point: Always set the ceiling to be about 0.2db below maximum level creating a tiny little gap between the top of the peaks and 0dB. If you are mastering loud, or ‘hot’ as some people call it, set it even lower, -0.4dB perhaps. There are a couple of reasons for this:
Some software’s overload indictors (red lights) will trigger, indicating that clipping has occurred when a peak reaches 0dB regardless of whether it’s actually clipping or not.
Inter-sample peaks. This subject veers off a little from the kind of tuition provided here but it’s important to mention it. Basically, even though you have your limiter set to catch any stray peaks, some peaks may still reach higher than 0dB during the conversion process from digital to analogue within a music playing system. This is down to how the digital signal is converted from absolute numerical values to the smooth curvature of a sound wave. The smoothing process can cause peaks to jump higher than the actual numerical values they represent in digital form in order to find the smoothest curve. Setting your ceiling to be lower than 0dB helps prevent problems caused by inter-sample peaks.
The next section is a short video demonstration of the use of a limiter at the end of a basic master chain.
Next page… Demo of a Limiter