Beginners Guide To Synthesis

Waves

Waves Types

In the basic form of synthesis you will start with a pure sound wave. This is called a sine wave. A sine wave is a sound wave that only consists of 1 frequency. This wave can only be produced by man.

Sine Wave

Sine waves can be very useful in synthesis as they give a very precise frequency and tone. People will not normally use this on its own but they will use it to create some great sounds once putting it through different processes to create the sounds that they want. Here we have an image of the frequencies that a sine wave if producing. Although Logic is showing that a few frequencies are playing here, a sine wave is just a single frequency with no harmonics. Logic is a little inaccurate here but I shows the basic principals.

Square Wave

Sawtooth Wave

Square waves. A square wave is another pure wave form but this time its made from several harmonics to make up its tone. This is a bit more crunchy and distorted then a sine wave. It can be more useful to start with depending on what sound you are looking for. This wave looks like like a square rather than a regular curved sine wave. This is what gives it a massively different tone to a sine wave. All these waves have different tones because of their shape and that gives you different starting points to shape and modify your sounds.

The third sound wave type is a saw or sawtooth wave. This again is made up of many harmonics that create an even more fuzzy sound which is another way to start off a sound. A saw wave is very similar to a square wave its just more fuzzy and crunchy in tone. This wave is made up of sharp jaggy lines like a saw which gives this wave its tone.  You would use this if you wanted to make something quite distorted maybe a bass line as this tone can be good for distorted bass.

Triangle Wave

Finally you have triangle waves which look like
little triangles. This one is not at all as fuzzy and crunchy as the square or sawtooth but its still not as plain as the sine. As you can see from the multimeter there are a few harmonics in this wave and it gives a less and more of a tones for maybe a lead. What is great about each of these waves is they all have a different character to them which can hep you pick depending on what sound you are trying to make. They all sound very different and I like how versatile you can get with them using different methods in synthesis.

Acoustic Theory (Frequency)

Sine Wave

In the drawing below it shows a sine wave and the basic parts to it.
The wavelength is determined by the length of one peak and trough of a wave. This is a called an oscillation. The bigger the wave length the lower the pitch is and the biggest the wave will be

The amplitude is the height of the wave from the centre line in which the wave oscillates above and below. The bigger the amplitude the louder the sound is.

The frequency measured in Hertz (Hz) can be calculated by the amount of times a full wave lengths happens in 1 second. For example 400Hz would mean the wave oscillates 400 times in 1 second.
When the frequency gets very low the wavelengths can get extremely long being meters long so sometimes you might not even have enough space in a room to physically produce a particular frequency without it being reflected off a wall before. Its really good to understand this when producing music, especially electronic music as it really help when putting tracks together. When you know a little science behind what you are making I think it can help make the product even better.

Filters


In synthesis you have what are called filters. These are designed to be able to literally filter out different frequencies of a bass line or any sound that you've created. There are three basic filters the first one is a 'Low Pass Filter' or (LPF). This will take away the high end of the sound allowing the high frequencies to pass through. In this video I have shown an example of the LPF on the multimeter. Low pass filter is really good if you want to just take a notch off the high end if it was getting in the way of something else in the track or if you wanted to just have more bass in your bass sound.

A high pass filter or HPF does the same things as a low pass filter but instead of cutting off the high frequencies it cuts off the low bass frequencies. This is really useful when you have a melody or a sound that had a lot of brightness but there are some frequencies that are a little to low and disruptive, its nice the just smooth them off. This is a really useful tool and I love using this even guitars as well as synths.

The last filter is the 'Band Pass Filter' (BPF). This is a more specific filter as it allows to filter out more frequencies and boost a few specific ones. This would be really good if you wanted to boost one practical part of a synth that you felt wasn't sitting in the mix just right. As well as you can choose a very specific frequency to cut. This is a bit like EQ but you can filter out a specific frequency that might be getting in the way of a vocal. This is a very useful tool I have found.

Whats great about the filtering features is that they allow you to shape your sounds and create musical interest by automating the LPF, HPF and BPF. This is not just select to electronic and synths which is great. I have even used LPF in my band when I have cut off the high end and allowed it to build up for when the song builds up. This is what  I love about the filters is that it has so any uses and can be applied to so many genres and styles for music interest too as well from an engineers view when mixing. 
Envelopes

Envelopes

An envelope is another way of manipulating a sound. It is a feature that you will very often find on any synth. An envelope normally has 4 main things you can change and these will be effecting the lengths of the sound which I will explain now. You have 4 tools in and ADSR envelope. This stands for ATTACK, DECAY, SUSTAIN and RELEASE.

It is a way to automate different aspects of the synth sound. The attack, decay and release are all time parameters where as the sustain is an amount or level parameter.

Attack: This is the first bit of your sound. The attack parameter determines the speed the attack takes to reach the loudest part. The fader that adjusts this determines how quickly this happens. If you have a really short attack with the fader down at the bottom, as soon as you hit the ket your sound will shoot to max velocity. If you were to put it right at the top you would get an almost fade in and the attack would gradually build up. This is the firsts part of your sound and how quickly you want to be able to hear it is determined by the attack. 

Decay: Decay is the second part of your sound this is the point in which the sound is at its loudest and the decay its how long it takes to go from the loudest point to the start of the sustain. A short decay will have a sudden drop to the sustain level. A long decay will have a slow fade down the the sustain level. This is a really important part of the sound. 

Sustain: Sustain is not a time parameter but is a level parameter. The sustain is infinite time. The time of your sustain depends on how long you hold your note. The fader controls the volume of the sustain not the length of time it holds for, you do that with your finger. This happens after the attack and decay.

Release: This is the very end of the sound where your finger comes off the key and depending on how long you set the release to is how long the sound will last for. As soon as your finger comes off the key the sound will start to release, if you had the fader to the bottom it would cut off as soon as you remove your finger. If you were to put it right to the top the release would last for a very long time before fading out. if you were making a melody you probably wouldn't have the release for too long but you also might not want it to cut off immediately. This allows you to control how long the sound releases for which is a massive part in creating your synth sounds.

ADSR Wave

Envelope Settings

Here is the settings that I have put to create a clear wave form where you can see all four parts. The steep up at the start is the attack which was around middle. The decay is the down steep also at middl. The sustain is the song straight, this is how long I have held the key for. The release is the tail that fades to 0.

LFOs/Routing

The Low Frequency Oscillator or LFO is a way of controlling the sounds in the synth. The LFO doesn't actually make sounds on its own it has a set of controls that you can use to control different parts of the synth. 

The LFO is there to create a rhythmic pulse that you assign different tools that you want the pulse to effect such as volume, pan or filters. You can assign this LFO to synced which is in time with your tempo of the track. For example this would work really well if you wanted to have a siren sound that was in time with the track because you could have a LFO controlling the pitch to make the siren sound and then another one if wanted it to match the drum tempo. This feature is really good for that. You can also set it up the pan, which means you could have a synth sound that would be panning left and right in time with your track or not if you didn't want it to because its also can be set to free custom timing. This is good if you don't want it to match the tracks tempo.

As well as having these features the LFO in logic has a great routing system meaning you can link 10 things to the LFO at the same time on this particular synth

I have been using all of these features that I have spoken about in many different ways and they are all great. They can be used for so many different things and in so may different ways.

I have been using the filters myself outside of synthesis for a more mixing technique on guitars. I have used them to take out the high frequencies and slowly bring them in for a musical interest. The point is that although in synthesis these are important tools they can also be used outside of this but in very similar ways. This has really helped me come into the world on synthesis confident because I have used these tools in similar ways which in theory you are doing the same thing to it. 

By learning the basics to synthesis it has completely opened up possibilities in music production and also gives you wider knowledge of what is actually happening and how you can recreate sound that you hear. 

Having a good understanding of the basic scientific ways in which sound works is also a massive help because it enables you to visualise what is happening and give you a better understanding of what you are working with. 

Images from:
www.songsofthecosmos.com
classicalgaming.wordpress.com
http://en.wikipedia.org
people.ece.cornell.edu
www.allacronyms.com