Audio effects explained - A quick guide for beginners
Firstly, let me comment on the difference between an effect and a process.
A process is something that makes your vocal, instrument, or mix better, but isn't something your listeners would particularly notice, nor consider very much different from what you might hear as an acoustic sound.
An effect on the other hand is something that grabs the ear's attention, and most likely wouldn't be possible outside of the DAW or recording studio.
Examples of processes
Equalization is normally a process. It is used to correct frequency-balance faults or improve the frequency balance of a vocal, instrument, or mix.
Compression too. It is often the case that the loud parts of a recording or mix are too loud and the quiet parts too quiet. So compression is used to even out the dynamic range. This is a process.
Other processes include level, pan, stereo width, noise reduction. There are more, but you can see what I mean.
Examples of effects
Can I leave reverb until later, please?
Probably the most classic effect is delay. This is where you hear an echo of the sound shortly after the original. Typical delay times range from 40 milliseconds to maybe 400 milliseconds or so. 40 milliseconds is a very short delay but it is perceptible as such. Beyond 400 milliseconds, delay has less and less musical value although - if you're inventive enough - you might find a use.
Delay can be turned into a repeated delay, which once upon a time was often called 'spin echo'. I like that term and I continue to use it. This is done by feeding the echo back into the signal chain. It goes round and round getting quieter on each turn. Or if you're into 60s-70s style Jamaican dub, you can briefly increase the feedback so the echo gets louder. Handle with care.
EQ and compression
I said that these are processes, and they can be. But they can also be used as effects. Equalization can be used to create a frequency balance that is totally different from what you'd hear in the real world. Likewise, compression can squash down the dynamic range of a signal so much that it is completely different from the raw vocal or instrument. Just do what sounds good - That's all that matters.
Warmth and harmonic generation
In audio, we often talk about distortion. In the olden days, there was always too much and we tried our best to get rid of it. But when digital audio came around and distortion vanished into inaudibility, we came to the view that we had thrown the baby out with the bathwater, to an extent.
So now we use plug-ins to create distortion intentionally. A little 'harmonic enhancement' - as we now call it - can make a vocal, instrument, or mix sound warm and snuggled-up to the ear.
Phasing, flanging, and chorusing
You can do this in real life. If you're bold enough.
It works best outdoors. Find a solid brick or concrete wall that's quite high - 3 meters or more would be a good height. Stand at a distance of around 30 meters. That's not critical at all so approximate as you please.
Now sing a loud, continuous note in the center of your vocal range, and run at full pelt towards the wall. Keep singing.
OK, now everyone thinks you're weird.
But what you will notice is that your voice suddenly becomes fuller and richer. Almost like two people are singing at once.
The reason for this is the Doppler effect. Because you're moving, the echo from the wall comes back at a different pitch. It mingles with the sound coming from your mouth directly into your ears, and you hear an effect similar to flanging.
Phasing, flanging, and chorusing use more convenient methods to achieve a similar sound. You won't often hear these sounds in real life, but they can sound great in your music.
OK, you should now have the idea. But what about reverb? Why have I left it till last?
Well, reverb is something that happens in real life. So if you have a close-miked dry recording and add reverb to it, it would really qualify as a process.
But reverb is often used quite unrealistically, in which case - by my definition - it becomes an effect.
It doesn't really matter what you call it as long as it sounds good.
So there you have it - a quick guide to effects, the difference between processes and effects, and, of course, there are more processes and effects that I haven't mentioned here to discover. And the important point is that the only thing that really matters is that your music sounds good!