I recently, finally, got an analogue synth after only ever using digital ones. I have always been a bit suspicious of digital synths. There was always something off about them. Now that I have had the chance to use an analogue synth first hand I have had my suspicions confirmed: analogue synths sound better by far.
Now, some digital synths are designed to do things that only digital synths can do, so comparing those to analogue synths is a bit unfair. It is true that digital synths have a wider range of timbres and easily do arbitrary control routing; limited only by software architecture, CPU and UI/EX, but digital synths all suffer from the same artifacts.
If you hunt around online you will find people raving about how particular digital synths so well recreate the classic analogue sounds. To some extent this is true, analogue model synths do a good job of recreating the overall tonal characteristics of analogue synths but they also suffer from some of the following:
- Aliasing – they all have some amount of nasty harmonic distortion caused by sample aliasing. Some do reduce this to a minimum bit it’s always there.
- Scratchy transients – they just can’t seem to handle situations involving high/short envelope settings in which you get nasty split, crackly distortion in onset transients. You often want a spike at the onset of a sound to give it a snap that your ear can catch hold of, so you might have a short envelope opening a filter momentarily, but this often introduces some scratchy high frequencies or crackly transients.
- Gritty high end – By far my most serious complaint. The thing that always puts me off. The high frequency component in every digital synth I have ever used always has a kind of brittle, rough texture. The sound is like subtle bit-depth reduction all over the top end. Digital synths never fizz cleanly and I always find it distracting.
- Bad aliasing during even subtle pitch modulation – one of the main characteristics of analogue synths is looseness. Pitched oscillators will slide around, if only very slightly. Many will recreate this via slight pitch modulation, say settings an LFO to wobble oscillator pitch or using some pitch shift plug-in, but these, even very subtle, variations immediately incur aliasing with a lot of digital synths.
- Break down at all extremes – digital synths always break apart with extreme settings. You can’t have LFOs going too fast, fast attack envelopes crackle and spit, high resonance sounds aliased, high register notes sound scratchy.
- Unstable low end – I have noticed that, to my memory, every digital synth I have used unravels on very low frequencies depending on settings. The low end seems to be detached from the rest of the signal. Maybe something to do with phase coherence of digital filters. Dunno.
It took me about 5 seconds using an analogue synth to hear that none of these problems exist in the analogue world. You can get an analogue synth to play a note at very high pitches and while the sound is whiny and difficult to listen to it sounds pure and intact. The high end is generally exactly as you would want to hear it.
On a subjective note analogue synths also have a kind of unruly quality that not many digital synths really have. With digital synths you set something and the synth hits it bang on every time. Analogue synths (and in fact gear in general) seem to be a bit more squirmy and springy. The sound also has more depth than many, but perhaps not all, digital synths. You can somehow tell that you are listening into a mechanical device, which you are. The sound is coming from a real thing and exists. Digital synths often have a flat, two dimensional quality, as if you are listening to cardboard cut-out impression of a sound.
Analogue synths probably aren’t for everyone. Sound is very subjective and I am only following my own taste. They are also kind of a pain in the arse to use compared to a VSTi. I now have ground loop issues for a start, but I have already had a quick test using the synth in a track and found it just added something great, processed beautifully and joined right in with the rest of the track. It recorded in one take and the result was just… perfect.