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Introducing Saturate 1.10!

(More Good Harmonics, Less Bad Aliasing)


I’m happy to announce that Saturate 1.10 has three new features to make it much better at adding pleasing harmonics to your mix, buss, or track.


1. Anti-Aliasing (sort of like oversampling, more on this later)

2. Symmetry Control for adding even harmonics

3. A Ceiling Control which allows you to set the level of clipping

 

Aliasing


The most common question we get about Saturate is: “What sample rate does it run at?” or “How much oversampling does it have?” and until now the answer has been “No oversampling, it runs at your native sampling rate.” which is the right answer for a complicated reason.


The reason to use oversampling in a DSP algorithm is to reduce aliasing. But what is aliasing?


A tonal sound is made of a fundamental frequency and a number of harmonic overtones. Adding distortion to that signal will generate more harmonics at higher frequencies.



Spectrum of a harmonic signal with frequency f0 (showing both positive and negative frequencies 🤯)

When working with digital audio this spectrum repeats itself back and forth forever. (These repeated copies are the aliases) The spectrum now looks like this…

Spectrum of a digital harmonic signal with images above and below the Nyquist Frequency

If we increase the distortion and the harmonics go above the Nyquist Frequency (½ the sampling rate) they bleed into the adjacent copies and the harmonics from the adjacent copies bleed into our main copy - resulting in harmonics that are not harmonically related to the fundamental.


Adding distortion causes aliasing from the images above and below

Even when we convert that audio back to analog to play it through our speakers, those non-harmonic harmonics remain - that doesn’t sound good.

Even when the images are removed the aliasing remains

Anti-Aliasing vs Oversampling


The simplest way to avoid these aliased harmonics is by oversampling, which raises the Nyquist Frequency and moves the images further apart, but it’s very inefficient. An oversampled algorithm needs to be run 8, 16, or sometimes even 128 times as often as a non-oversampled algorithm - depending on the amount of oversampling.


This uses a lot of processing power, but there is a more efficient way. Saturate 1.10 uses a method called anti-derivative anti-aliasing to avoid generating the aliased harmonics, it works as well as very high oversampling, but it uses much less processing power.



What This Means for Your Music

The thing to remember is that the problems associated with aliasing are all about harmonic sounds, this means sounds that have a pitch or tone. The most popular use case for Saturate is to lop the tops off your drums to give them more boom. If that’s what you’re doing the ANTI-ALIASING button isn’t going to make much of a difference whether it’s on or off - using the DETAIL PRESERVATION slider to dial in the amount of detail you want to preserve is going to be much more important.


However, if you’re trying to add pleasing harmonics to an entire mix then yeah, please slap that ANTI-ALIASING button and it might clean up the sound a bit. As always - use and trust your ears, how it sounds is all that matters.



About Those Pleasing Harmonics


A tried and true method for adding pleasing harmonics to a sound is a method called asymmetrical clipping. It's commonly cited as the reason vacuum tubes sound so good, but it makes musical sense, too. If you think about the harmonic series as musical intervals and list them in order you'll see...


  1. Unison

  2. Octave

  3. Octave + 5th

  4. 2 Octaves

  5. 2 Octaves + M3rd

  6. 2 Octaves + 5th...

Now you see why the harmonics are called harmonics, but you'll also notice that the even harmonics shown in orange are quite pleasing. You can still make a chord without those intervals, but if you add them in it that chord will sound much richer.


It turns out that when you distort the top and bottom of your waveform exactly the same way you’re only adding odd harmonics (1, 3, 5, 7, …). When you change the shape of the distortion on the top and the bottom you add even harmonics as well (1, 2, 3, 4, 5, 6, 7, …). That’s twice as many harmonics in the same sized package, for a much richer tone.


Saturate’s new SYMMETRY control allows you to change the shape of the distortion on the top and the bottom. This subtle control allows you to blend in these additional even harmonics to taste, so enjoy.


Overshooting Your Target


One downside of anti-aliasing, no matter how you do it, is that it creates a phenomenon called overshoot. While you might expect a clipper to clip your audio to 0dB, once you add in oversampling or any form of anti-aliasing, the output will overshoot that target and you’ll see it on the meters.


But never fear, we have provided three solutions…


  1. The HARD LIMIT button will engage a final clipping stage that will make sure the clipper never outputs audio above 0dB. However, this will re-introduce a tiny bit of aliasing. You’ll probably never hear it, but that's the tradeoff.

  2. Reduce the CEILING. Saturate has a new CEILING control will allows you to control the point of clipping. By pulling this down a bit you can make sure you’ll never peak above 0dB.

  3. Do nothing: In a modern DAW it doesn’t matter if your peak is over 0dB unless Saturate is your final stage. Again, use and trust your ears, if you can’t hear a problem then there’s no problem.


Thanks for reading about Saturate 1.10. If you haven’t already grabbed the free update, go get the installer here.


Also, Saturate 1.10 is on sale here, or as part of the full Elevate Mastering Bundle.


Thanks, Dan

In addition to major feature explanations like this, we've been posting fun things on Instagram, Twitter, and Facebook. Come check them out.




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