There is nothing worse than envying a synth sound that someone has created, and not being able to replicate it. The fact is, that musician has likely spent hours working on cool sounds and so you will most likely have to as well. You can end up creating a familiar sound entirely by accident of course but moments like that are few and far between. Of course, it is always better to create your own for your own personal style but sometimes you just know the sound you need and can go for anything less. So, here are my tips on recreating the sounds.
1. Understand What You're Hearing
The very first step is to understand where to start. There is no point trying to replicate a sound that isn't even a synth in the first place. Consider the easiest route. For example, the sound may be a heavily effected sample run through a sampler, in which case, your best bet is to identify the sample and take that route.
Do some research, it may be a hardware synth for example the Synclavier as heard in the intro to "Beat It" (below). In this case, you should start looking for a VST emulation of that synth and your life will be so much easier. Often there are patches and presets available on a number of platforms.
Learn the most common types of synthesis sounds. You'll have a hard time replicating some more complex FM (frequency modulated) sounds on a purely subtractive synth. Needless to say, at least a passing understanding is further needed to then use each type of synth.
2. Understand What You're Hearing
Listen and analyse the sounds, is it one synth or is it several layered? If so you should try and separate the sounds. For example, it may be a midrange synth with a subline following the root notes underneath. My best advice is focus on the midrange first as that will be the most recognisable portion.
Play around and match the octaves and waveforms, it certainly won't sound close yet, but you need to start somewhere.
Consider how many voices there are, if it is a single voice, it can sound quite thin. If there is a thicker sound, there is often several voices, slightly detuned from each other. This will create a sound where the notes almost "wobble" in and out of phase.
Consider "Yeah" by Usher. The main synth has that thick sound. Try adding some phasing and chorus on a trance saw lead. A knowledge of effects, as with synthesis is paramount.
3. Understand What You're Hearing
A big change to the sound is how many notes the synth can play (monophony/polyphony). If the synth is only playing one note, and it slides up to the next, it is likely monophony with portamento. If it slides up on the same note hit, Retrigger is likely disable. If each note hits again, retrigger is likely enabled.
Is this main synth monophonic or polyphonic? Listen to
the most complex section and see if the melody is able to
play chords or single notes.
Voodoo people is a brilliant, beautiful riff. Listen to the sound and you will hear the same note sounding very different depending which note it has slid off. This would lead me to think there are several voices interacting in the same note, their varying phase emphasised by the high resonance and distortion.
4. Understand What You're Hearing
Are all the notes the same volume and expressed the same? If so, velocity is likely disabled. Obviously if not, velocity is enabled and you'll have to hit the keys appropriately hard and soft.
Consider the attacks of both the filter and the amp envelope. For a more "strings" sound a longer attack. For a harder hitting sound, there is likely a very short attack.
Likewise, the sustain should be appropriate to the sound, as should the release. Consider the popular bigroom "woodblock" sound popularised by the drops in Knife Party in "LRAD" and Martin Garrix with "Animals".
Both have a very short lasting note where a lot of the content lies in the reverb around it. Sometimes the settings of the effects can be more essential to the sound than just the source of the synth.
While circlejerked a lot, and considered Noob material now,
don't lie and say this track didn't blow your mind at it's release.
5. Understand What You're Hearing
Sometimes something like compression completely changes the synth sound. I've made really filthy bass synths and had a song go one way, but as soon as it is sidechained to the kick, EQ'ed, and mixed to the lead, it sits in the mix and becomes a lot gentler.
Consider working to the rough sound first, then moving on and making it sit in the song first. Then return to the final bit of the synth design once all the processing is applied. You may find you only need to open the filter a bit and add some more distortion.
What I'd recommend is you have four or five different VSTi synths, each capable of different things (FM, additive, subtractive) to maximise what you can do straight from the inspiration. There is nothing worse than having an idea and having to scroll through VST sites to find what you can lay it down on.
There are plenty of free VSTi's capable of all the above and with the addition of free effects VSTs, you should be able to make more or less any sound.
Always save your presets so you can go back. This way if you come across a sound that you know is similar to one you have saved, half the work is done and you only need to fine tune.
Never overwrite a preset either. I now have presets called "Funky Bass", "Funky Bass 2", "Funky Bass 3" and on as I make small adjustments that I like. It means I can have an idea and just scroll through similar presets to find the one that fits. It also means that they are all in the same style and so could still al be recognisable as my synths.
Watch tutorials and visit Reddit's r/synthrecipes which is a site of requests for how to make certain sounds. Just spend your time lurking there and watching the videos and you will see how people work to recreate a sound, if you have any issues the community always helps.
Never limit yourself to other peoples sounds. Spend a day or two just focussing on making cool presets, regularly saving anything you like or that has potential. You can always revisit them.
One cool thing is presets can be shared and so if you get confident, swap with your friends and double each other's preset banks, you'll be able to thank each other later. Just make sure they are descriptively labelled.