- What is a synth pad?
- How do I make a synth pad?
- ADSR basics of creating your own pad sounds.
What Is A Synth Pad In Music?
A synth pad is a soft, often elongated sound designed to ‘pad out’ a track or section of instrumentation. This is in contrast to a synth lead which would be much more staccato and at the forefront of a mix.
A pad could refer to anything from a soft ambient background drone to a more conventional chord progression that follows the track’s key.
The characteristic that makes it a pad is the way in which it fits with the song, whether that be filling in gaps to enhance the overall mood or simply combating some of the harsher elements that may be being created by a lead part.
Frequency Content Of A Pad
Frequency content can also play a part in what constitutes a pad.
Typically a pad would occupy low to low-mid frequency bands as it’s these frequencies that give the effect of ‘padding’ out or filling the mix.
Higher up the scale, you’ll start to encounter harsher frequencies which won’t give the listener the sense of gluing a track together.
That’s not to say that a pad CAN’T occupy higher frequencies.
If a pad is replicating the sound of strings for example, you may end up with a lot of high-frequency content.
What makes it a pad is the legato feel and timbre, however if you were to switch from soft, smooth playing to short, stabbing notes then you’re creating more of a lead feel than a pad.
ADSR
To fully understand how a pad works it’s important to understand ‘ADSR’.
‘ADSR’ refers to a set of four parameters which when tweaked can produce very different synthesized sounds
A: Attack
When we hit a key on a synthesizer that sound will take a certain amount of time to reach its full level (the time from silence to the time when the note becomes the loudest).
Think of it this way — a snare drum would have a fast attack, as soon as it is hit it will reach its maximum volume (to be precise it actually does have SOME attack time, we’re talking milliseconds, not enough for the human ear to pick up on).
On the other hand, if we imagine the sound of a violin string being played slowly, but gradually getting louder, this would be a very slow attack time. Much is the same with a pad.
The slow attack time stops the sound becoming to sharp and snappy, or even percussive and will result in more of a swelling effect.
Listen to the audio examples below, the first utilizes a short attack time, whereas the second utilizes a slow attack time.
D: Decay
This refers to the time it takes after the attack reaches its peak for the signal to decrease to its sustain level.
Much like the attack time, the decay of a pad will typically be quite long although it is possible to create a pad sound with a short decay time.
We’ve used the same audio examples below but compared the two with a short and long decay time. Notice how for the purposes of creating a pad, a short decay sounds quite unnatural and odd.
The decay can be a little difficult to understand at first. A good analogy is to imagine how a guitar string vibrates.
If you pluck a guitar string there will be an initial spike in the sound (representing a fast attack), however after being plucked the string will settle into a period of vibrating before eventually running out of energy and becoming silent.
As the string settles after the initial pluck into a few seconds of sustaining, this would be referred to as the decay time.
S: Sustain
The sustain refers to the persistent (or held) note.
The note will play at this specific level before dropping off. Technically however a note with a high sustain level could play indefinitely.
A higher sustain represents a longer time before the note will finish and a shorter sustain will result in the note finishing sooner.
Much like decay, a pad could, in theory, have a short sustain time but in order to achieve a softer timbre a longer sustain time or usually most suitable.
Again, we’ve used the same audio examples below but with a very short sustain vs a longer sustain.
R: Release
The release time is the final stage of a synthesized sound which represents the period after sustain in which the note finally ends.
A slower release time means the note will take longer after the sustain period to reach zero, and vice versa a quicker release time results in the note reaching zero sooner.
A pad would usually incorporate a slower release time to ensure that the note doesn’t suddenly stop, which would contradict the legato and flowing feel.
Using a release value that is too long however can cause an unusual sound when changing notes or chords due to end of one sequence playing over the next. This can cause a muddy and sometimes clashing effect.
Hear the differences between a short and long decay below, and how they overlap with the sections that follow.
Achieving A Pad Sound Using ADSR
It is important to consider the overall sound you are going for when tweaking your ADSR parameters.
For example, it may be that you want a dreamy effect with a short break in sound between chords, in which case a slow attack and fast release will suit your needs.
It may be that you only want one long sustained note, but you need it to start on the first beat of a bar in which case a faster attack may be used but the softer timbre of a long sustain and slow-release will fill out your sound.
As we’ve mentioned there is no strict definition of what a pad is.
But the idea of ‘padding’ out a sound is a great place to start when getting to grips with your parameters and sounds.
Have a question about pads? Leave em below in the comments!