Different Effects in Music Production — Harmonic Effects

Let's take a look at EQ, filters, bitcrushing, saturation, and distortion!

Being able to break down the countless music production effects into sensible categories is a really useful way to get our heads around the different ways we can shape the sounds we create! We’ve taken a look at time based effects like reverb, delay, and more, and we’ve also looked at dynamics effects like compression, limiting, gating and so on. This third category of dynamics effects focuses on changing the character of sounds and rounds off the basic, broad brush strokes categorisation of the types of effects we can use when making music, so let’s dive in…

Filters

The concept of a filter is everywhere — from coffee to Instagram. When we filter something, we choose what to keep and what to separate away, and when we do it with sound we’re generally thinking about frequencies. There are various types of filter that we use to separate different frequencies, depending on our use: low pass, band pass, high pass, notch, comb… the list goes on, but the concept is always the same. Some frequencies ‘escape’ the filter unchanged, others are separated out.

It’s easy to figure out what kind of filter to use to get the sound we’re aiming for. Too much high frequency information in a signal? A low pass filter lets low frequencies past, removing high frequencies. Just want a the mid range? A band pass filter sets a frequency band that gets past, and removes the high and low frequencies outside that band.

There’s plenty of depth to the controls on a filter. The ‘slope’ control will adjust how aggressively frequencies falling outside the filter’s ‘cutoff’ are removed, from very steep to very smooth. The ‘resonance’ of a filter is a control that gives a little boost to the frequencies right around the cutoff point, which is especially useful when moving a filter’s cutoff point to give a musical quality to the filter as the frequencies around that moving cutoff are accentuated. Fundamentally, though, filters separate frequencies away from a signal.

EQ

EQ, short for ‘equalisation’, is a step on from the concept of a filter. Instead of just thinking about removing frequencies from a signal, EQ can boost frequencies too. There are tons of different interfaces for an EQ device, each with their own strengths and weaknesses, but the goal of them all is to allow us to ‘shape’ a sound.

An EQ will generally have the ability to affect various frequency bands in a signal, from low to high. The amount of control we get over these bands is down to the way the EQ is designed, with a ‘graphic’ EQ splitting the frequency range into rigid bands that can be cut or boosted, and a ‘parametric’ EQ giving us the ability to define where the central point of a band is and how wide the band is before boosting or cutting it. There are ‘semi parametric’ EQs that might allow a degree of control over a band’s central point, and all sorts of weird and wonderful implementations of EQ that are specialised to workflows — perhaps only allowing certain bands to be adjusted, or ‘intelligently’ changing the width (often referred to as ‘Q’) as the cutting or boosting becomes more pronounced.

Because EQ can be boosted and cut across multiple bands, we run the risk of getting issues with phase where the bands of the resulting audio don’t quite fit back together again quite as neatly as they once did. This is where the concept of ‘linear phase’ EQs come in. Generally, it’s a good idea to use EQ fairly sparingly, and cut bands and raise the overall signal level rather than boost bands, but as always our ears are the best way to tell these things!

Bit Crushers

Just because digital audio recording has gotten to the point where we can be pretty much completely transparent and indistinguishable from an organic sound source doesn’t mean that we should always be aiming for this! Early samplers were much more limited in their ability to capture a signal accurately, and this gave them a character that when utilised smartly provided a very pleasing sound. Simulating this reduction in sampling accuracy with a bit crushing device is a great way to get an interesting, thick, characterful sound.

Because when a sound is sampled we have to choose the bit depth we sample at, essentially the accuracy with which amplitude can be recorded, using a bit crusher to reduce the bit depth of a signal gives us an effect not unlike a compressor, reducing the difference in volume between loud and quiet signals. Adjusting the sample rate of a bit crusher will reduce the accuracy of the frequency range that can be captured, and will have the effect of both giving a filtered sound to our signal where the highs and often the lows will be captured in less detail and creating aliasing, where similarly harmonic frequencies are ‘grouped’ together and become stronger. With the right settings, the right signal, this aliasing can sound musical and characterful.

Bit crushers range in their complexity from simple knobs for bit depth and sample rate all the way to complex emulations of classic devices, with the algorithms for the choices they made about which frequencies and amplitudes to keep and any mitigations for the — at the time — undesirable effect of the inaccuracy, like quantisation and jitter, selectable and adjustable.

Saturation

When a signal goes through a device too ‘hot’ (loud) for its maximum amplitude to be recorded accurately, depending on the device a variety of things might happen. Because we so often work with digital and software equipment, using sounds that have already been recorded or are generated virtually, saturation devices can be used to affect the audio in a way that simulates the signal going through a device and exceeding its limits.

As the peaks of a signal ‘clip’ the maximum level a device is capable of recording, the way these clipped peaks are dealt with changes from device to device. Digital devices will have a harsh, inharmonic sound that at one point in history was a ‘never do this’ but, like all things, has found its place as an effect. Analogue devices tend to have a more harmonic effect on the clipped peaks, creating a warmer, thickening sound. Both methods will have a compressing effect on the signal, because the lower amplitudes are raised toward the maximum amplitude ceiling while the peaks are flattened and changed in character without actually getting louder.

The key point of saturation is that the signal fundamentally sounds the same, but with a bit of extra ‘sauce’ — like adding seasoning to a plate of food. Good saturation gives ‘strength’ to a signal, a gutsy, forward sound that adds character to the peaks and pushes the overall level of a signal upwards, whilst still retaining the central character to the sound itself.

Distortion

Take the concept behind saturation further and we end up with distortion. A distortion device takes a signal and pushes it past the point it still has its original character, to the point it begins to take on a completely new sound. Often, the same device can be used to subtly saturate a signal when it’s used at low drive settings, and as it’s pushed higher it begins to distort the sound beyond recognition.

Of course, there’s more to distortion than simply overdriving a signal, with countless devices specialising in different ways of taking the original frequency content and altering it into something new. Multiband distortion devices are interesting in that they split a signal into different frequency bands and allow each to be overdriven, so that the lower amplitudes can be distorted without their relative amplitude changing compared to the overall signal. Regardless of the technique they use, distortion devices have the same goal: take a sound and change it, usually into something more aggressive sounding.

More Depth

The goal of these posts has been to scratch the surface, demystify some of the terms of music production, and give you some confidence to dive in and make music using the devices available to you to get the sound out of your head into your DAW. Essential Music Production is the ideal next step, with detailed audio, video, and graphic examples of all the effects you’ll use to make music and all the crucial steps and stages of music production laid out in an easy to follow but comprehensive course. If you’re learning how to make music, this is exactly the course you need to accelerate your productions, so check it out now!

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