Outline the critical steps involved in mastering an EDM track, specifically addressing the use of limiting, compression, and EQ to achieve a target loudness level and overall sonic polish suitable for professional distribution.

Mastering an EDM track involves a series of critical steps that aim to transform a well-mixed track into a polished, commercially viable product, ready for distribution on various platforms. It’s not about fixing a bad mix; rather, it’s about adding the final layer of refinement that enhances the track's overall loudness, clarity, and cohesion. This process typically involves the strategic use of limiting, compression, and EQ, among other techniques.

The first critical step is to prepare the mix for mastering. This means ensuring that the mix is properly balanced, and that there is sufficient headroom. It’s important that any technical problems in the mix such as clipping, phase issues, or muddiness are resolved before the mastering stage. Aim for a peak level of around -3 to -6 dBFS to leave room for the mastering process, this is very important.

Next, the mastering chain usually starts with subtle EQ adjustments. At this stage, the goal is to make broad, gentle adjustments to the overall tonal balance. This is not the place to surgically fix mix issues but rather to enhance the track's overall character. For instance, a low shelf boost might add warmth and fullness to the low-end while a high shelf boost can add clarity and air to the top-end. Alternatively, a slight cut around 200-400 Hz might reduce muddiness. The important idea here is that the mastering EQ should be very broad and subtle to avoid changing the mix character dramatically. For example, a subtle wide bell boost at 80-100Hz can add a little low-end punch while a subtle high shelf boost around 10 kHz can add air and clarity. However it is important to monitor the results and make sure you are not changing the mix in an undesirable way, and if that happens to leave the EQ section out.

After EQ, compression is usually the next step. The purpose of mastering compression is different from mixing compression. In mastering, compression is used to glue the track together and add cohesion. This compression is usually very subtle, employing a low ratio (around 1.5:1 or 2:1) and slower attack and release times. For example, if we are using a vari-mu type compressor we might use a slow attack to preserve the transients, a low ratio to subtly reduce the dynamic range, and a slow release to make it sound more cohesive, and a low gain reduction. This subtle compression should bring out the low level detail, enhance the track's perceived loudness, and glue all the elements together without sounding squashed. This is very different from using compression on drums or other individual channels in the mix which may need more aggressive compression for dynamic control and punch.

Following compression, the next critical stage is limiting. Limiting is used to maximize the loudness of the track to levels that are suitable for commercial distribution. A limiter works by setting a hard ceiling on the track's signal, preventing it from exceeding a specific level. In EDM, it’s typical to use a very fast attack time and a release time that’s matched to the tempo to avoid unwanted distortion. The goal is to increase the overall loudness as much as possible without clipping or causing pumping and distortion. For example, we could use a limiter with a ceiling of -0.3dB and bring the input gain up until the limiter starts to reduce gain, which increases loudness. It is important to pay attention to how much gain reduction is being used because it will affect the sound and feel of the track. A common technique for loudness is using a low threshold of -1dBFS and then gradually adding gain to the input of the limiter to make the sound louder and fuller, while being careful of over compression and distortion. The limiter is a very important part of the mastering chain, and using it properly is key to getting the loudness needed for modern music.

Finally, a dither is used. When reducing the bit depth it is important to dither and this should be done as the final stage of the mastering process. Dithering helps reduce the quantization error that is introduced when you change the bit depth. This dithering should only happen once, at the final stage before export and it may need to be set up accordingly.

While these techniques are important, it's crucial to listen critically and make adjustments based on the specific needs of each track. The whole point of mastering is to enhance a good mix, and it is an important stage that should be performed thoughtfully and carefully. Also important is making sure that the mastering chain is not detrimental and that the track is better for it. Often it’s best to do the mastering process in a controlled and objective way, using reference tracks for loudness and tonal comparison. Mastering takes a lot of practice and experience and the best results usually come from a thorough and careful approach and the willingness to experiment and understand the specific needs of each song.