Basically, circuits are noisy, don’t give you the exact output you expect, and we’ve had to deal with it for so long that we’ve become accustomed to it and consider it a sign of good sound. This line stuck out at me
I wonder if in a parallel universe digital had preceded analog (somehow) would we be writing of ways to reduce warmth in our gear? If over decades of listening to clean digital recordings would we shudder at the sound of THD?
THD is Total Harmonic Distortion, or the way the circuitry bobbles the sound along the way, adding harmonics.
100% digital recordings have often been called ‘cold’, often by people who couldn’t tell the difference between an ice cube and a red hot charcoal briquette, but I digress. A computer is also subject to noise, but as long as it stays within range, a 0.00000001 will still be a 0 and a .99999999 will still be a 1. Thus a computer will output the exact same sound over & over with the only distortion being added by the final output chain of analog equipment (the DAC, soldered connections, plug, wires, circuitry in the speakers, etc.)
When sound engineers first started out, they couldn’t capture the same sound they heard because the primitive equipment added so much noise & distortion. Just listen to any early recording & you’ll hear the hiss, crackle, and the tinny sound.
Over the years, engineers fought & fought these limitations, constantly improving their equipment to eventually get rid of more & more THD. This ‘warmth’ we so crave in our current sound was garbage to the early pioneers who were trying to get rid of it! Well, to a point – at some point, that distortion became a particular ‘sound’ someone liked and started using to their advantage. Wasn’t too long ago that to get a really distorted sound, you’d have to cut the speaker cone.
I have a bunch of audio software that emulates old systems. You can control the voltage going into the amp, the angle, distance and type of the microphone from the cabinet (even placing them behind!), the size of capacitors, etc. for Guitar Rig Pro from Native Instruments. They also have a Moog emulator called Monark that, upon starting, takes a bit before it’s in tune and will ‘drift’ as you play it.
Often the unpredictability was what gave these instruments their distinctive sound & why old models are often prized. Digitally, it’s technically feasible to simulate every last bit of them, but even me, Mr. “I can do everything I need In The Box (ITB)” understands that sometimes, it’s just easier & more expressive to turn a dial or push a slider and just get whatever the instrument hands me.
Oh, this isn’t strictly related to audio. When I did 3D modeling, the first thing you learned that anything perfect looked fake. You had to add scratches, dents, dirt, or any number of imperfections to make something look realistic.
Just an interesting article that piqued my interest.