ok, I play
I've passed a 1khz sine (generated in Wavelab 6, 24 bit/44.1) though a few plugins, mainly compressors.
this is NOT a scientific test, because most of the comps have fixed times for attack and release, so is really difficult to match the settings and compare them all.
I'm not pretendig to say wich is good or bad, I'm not talking about the sound.
I'm just testing the harmonic distortion added UNINTENTIONALLY by the plugin, I mean ALIASING.
From the wiki:
In
signal processing and related disciplines,
aliasing refers to an effect that causes different signals to become indistinguishable (or
aliases of one another) when
sampled. It also refers to the
distortion or
artifact that results when the signal reconstructed from samples is different from the original continuous signal.
Quote:
Originally Posted by
andy_cytomic
➡️
Too much aliasing is a big problem, and will mean your audio suffers hugely - even though a listener might not be able to say "oh that's aliasing" if you do A/B tests with the aliased and non aliased version, they will prefer the non-aliased one.
Ok. Let's start.
You'll see attached the original 1khz sine.
every plugin will show some peaks.
The big peaks are harmonics, the small ones are not harmonics. These small peaks means the plugin is not being accurate with the original file.
From the wiki...
A
harmonic of a
wave is a component
frequency of the signal that is an
integer multiple of the
fundamental frequency
inharmonicity is the degree to which the
frequencies of
overtones (known as partials, partial tones, or
harmonics) depart from
whole multiples of the fundamental frequency. Acoustically, a note perceived to have a single distinct pitch in fact contains a variety of additional overtones.
So when a plugin has harmonic content, the sound is probably richer and can be pleasant to your ears. Most of the hardware adds this kind of harmonics and we love that sound.
In my test you can watch that the harmonics (big peaks) are 3k, 5k, 7k...being all of them multiples of 1khz (the original sinewave)
But when you see small peaks at 900, 800, 1100, 1200, etc, this is inharmonic content that doesn't sounds good. The sound becames less defined, more blurred, foggy...
Imagine you play the A key on a piano, but unfortunately you push at the same time a few keys next to the A that sounds at a lower volume than the A note. This A note will be the louder, but less defined, and less pure than if you just pushed the A key and nothing more.
So, when you add inharmonic content to the signal, you are adding a lot of notes that don't sound good in this context, but at a lower volume. You probably not hear them, but the sound looses definition, although you don't know the reason.
You and me probably can't hear nothing of it when this content is below -80db (as you can see in the graphics), but when the inharmonic content is above -60 and you stack a lot of tracks, the sound becomes less defined and dirtier to our ears.
This inharmonic content doesn't exist in the analog world, you'll never find it in the hardware, just the harmonic content.
Adding inharmonic content to the original signal means a reduction of quality. In a entire mix whith lot of tracks, this means less definition in the final sound, because you are adding a lot of notes that are not harmonics with the real ones in the music.
Aliasing is distortion added by the plugin. This distortion ever sounds bad, we're not talking about "warm" or "analogue vibe". The cause is a bad and poor processing and a sound quality loss.
Most of the plugins have very nice interfaces, some of them have a lot of features, but 90% have poor processing and they make your tracks TO SOUND WORSE, with less transparency because they're adding unpleasant distortion caused by aliasing.
Most of the time, we call this distortion "analog sound" or "color", but is just a matter of poor quality product.
In the next posts I'll upload some plots.
Because is very difficult to match the settings in all those plugins, I'll just do the test in different positions and different times. Gain reduction is always 6db.
All this measurements are made with native versions on Nuendo4 at 24 bit 44.1
Working at higher rates (88, 96, 192) the plugins work much more accurately and the looks cleaner than in 44,1.
Sorry for my english. I hope you'll understand this is my third language.
Look at the original 1khz sine