PreSonus Blog

Friday Tips: In Praise of Saturation

Sure, everyone sorta knows about saturation. But let’s drill down, give some audio examples that really get the point across, and explain how saturation can help everything from individual tracks to master tapes. Really.

To be clear, we’re not talking about the distortion that “flat-tops” a waveform. Fig. 1 shows a comparison of unsaturated, saturated, and distorted versions of the same waveform (using version 4.5’s new “smooth” waveform view feature).


Figure 1: The gray waveform is unsaturated, the blue saturated, and the yellow distorted.

Comparing the three, in the section outlined in red, the saturated version is louder but the waveform isn’t all that different from the unsaturated audio. The distorted waveform is louder than the saturated one, but the peaks are flattened. This is particularly noticeable with the negative-going peak highlighted in black. Flattening peaks produces the kind of nasty digital distortion no one really likes, but saturation is a different animal…as the audio examples will show.

Before going any further, if you don’t have the free Softube Saturation knob, go to your PreSonus account and download it from Products > Add-Ons (Fig. 2).


Figure 2: What are you waiting for? It’s free.

It’s a pretty basic module—turn the knob clockwise for more saturation (but I’ve never turned it up as high as shown in the picture!). Keep Low means it will apply more saturation to high frequencies, Keep High means more saturation for low frequencies, and Neutral means equal-opportunity saturation for all frequencies.

Saturation is great with drums, including mixed drums. You’ll get more punch and level (Fig. 3) that helps drums stand out in a track, without any of the artifacts (like pumping or breathing) associated with some dynamics processors.

Figure 3: The waveform for the drums audio example. Unsaturated is blue, saturated is red.

Now listen to the audio example. The first four measures are the unsaturated version, the last four measures the saturated one. Note that both were normalized to the same peak value. Even though the waveforms don’t look all that different, the saturated version really punches through—yet doesn’t sound “distorted.” This same kind of approach can also work well for bass.

 Now, let’s move on to saturating a two-track master. This may sound like a bad idea, until you realize that tape emulation plug-ins are basically just adding saturation, although some do it with a bit more finesse than a simple saturation plug-in (e.g., the Waves J37 provides different virtual tape formulations and bias settings). Fig. 4 shows the audio example’s waveform.

Figure 4: The two blue, four-measure groups are unsaturated; the two red, four-measure groups are saturated.

The audio example is excerpted/adapted from the song All Over Again (Every Day). I added a very slight pause between the unsaturated and saturated sections, although I’m quite sure you’ll hear the difference anyway. (To hear the final, mastered song—which of course was done in Studio One—click on the link.)

For this kind of application, you don’t want to apply too much saturation—a little bit goes a long way. As you turn up the knob you may think it’s not really making a difference, but it is. Toggle bypass frequently for a reality check. Fig. 5 shows the settings used for the master tape example.


And there you have it—we’ve done our shoutout for saturation. If you’ve missed out on the fun, load it in a track, and listen to what happens. You just might like what you hear!

  • Stuart Snyder

    This is a great plug-in, but it would be great if it had a master volume or output control.

  • The Softube “Saturation Knob” is just OK. I find that frequently on the way to a desired level of saturation, I get that awful, cracking sound of digital distortion. I get a much better result from the “natural” saturation I get from emulations of analog compressors, EQs, preamps, consoles, etc.

    That being said, I’ve wondered for some time how saturation, which is essentially distortion, can seemingly add clarity to a mix. Looking at these wave files, I’m thinking maybe it’s because saturating those high overtones emphasizes them without making them harsh. Something on that order, anyway. Does that make sense? Class? Anyone? Bueller? 🙂

  • Rod Kestler

    Yes – that’s clarifies what I’ve experienced – J37 is a complex plugin and I would have to study it to get the value it is capable of rendering. I have Kramer Master Tape, but I have yet to experiment with it enough to even have an opinion. And I wanted to throw this completely unrelated comment out, which is that for my mental workflow, Studio One is the best DAW. I’ve never used Logic, but that comparison is based on ProTools and Q-Base. It’s the UI – the richness of the graphics and the ease of workflow, plus the multi-monitor support alone make it a superior choice. I used to keep ProTools around for session conversion, but I don’t even bother anymore.

  • Brutus Undercroft

    Nice! I’ve been playing with putting an instance of it between my Master EQ, compressor, and limiter. Low levels for each one, obviously. But, the idea here is to more closely approximate an analog signal chain. Plus, each stage causes slightly different behavior, which is to be expected.

  • Anderton

    Well I don’t want to hijack the thread, but I just wrote a very in-depth article for Waves comparing the J37 and the Kramer Master Tape. The J37 has a lot of subtleties that aren’t obvious. I used the testing procedure described in a previous Friday tip to uncover the alignment subtleties – for example, you can’t adjust pre-emphasis/de-emphasis, but each of the formulations was EQ’ed a little differently. I didn’t really feel I understood what was going on with that plug-in until after hours (and hours!!) of research, coupled with years of dealing with tape, alignment, head azimuth adjustments, etc. I would NEVER go back to tape, though! Studio One suits me just fine 🙂

  • Rod Kestler

    Yes – I actually find the J37 to be almost too powerful most of the time – not subtle enough. The SoftTube Saturation Knob is great for simplicity. And I use Saturn for the more exotic or precision situations.

  • Rod Kestler

    Good point – I actually meant it in the sense that when you have a scenario where you want something to have a higher LUFS value, but not necessarily an actual higher volume in terms of RMS, saturation will get you that effect. But yes, of course, matching is an important step for comparing. I still have to remind myself of this from time to time. Hey – great article! You guys are writing a lot of very good content to support the DAW. I look forward to each installment, and I’m actually using several of the preset chains from past articles.

  • Anderton

    Thanks, excellent point – I should have mentioned that in the master tape example, the peak levels of the saturation and non-saturated sections were matched to make for a fair comparison.

  • Anderton

    Playing around with the J37 is what made me think “hmmm, I wonder how close I can come with the stock SO4 plug-ins.”

  • Rod Kestler

    Also…important to note that one track which is saturated and then volume matched to the original will often have a higher apparent volume. Saturation can also be used to smooth out hot spot frequencies in instrument or vocal tracks without applying any compression.

  • Rod Kestler

    I do quite a bit with saturation at the track level and in a more limited sense in mastering. The SoftTube Saturation Knob is great to have, and it’s good to have several saturation plugins for different kinds of sounds and applications. I cannot say enough good things about the FabFilter Saturn plugin for example, which has the ability to go from light tape emulation to heavy and highly altered sounding saturation and distortion. I use Waves J37 for tape and also Slate Digital’s VTM.

  • Anderton

    Thanks for the suggestion, something about the pros and cons of different effects orders would make a good tip. Look for it sometime in July.

  • The Softube Saturation is a very good saturation plugin. I like it better than some paid plugins. Sometimes I wonder how to put it in the FX chain. At first or last after EQ/Compression/Reverb etc. Maybe you can clear things up in another Tip. Anyway. Thank you.

  • Darin Browne

    Restart… The obvious solved again!!! Will wake up soon!

  • Darin Browne

    Just downloaded and installed it but it seems to have an error. Little yellow triangle and I cannot enable it. What am I doing wrong???

  • DarrinNoName

    Found it in the shop and then purchased it (For Free) and now it’s in my products.

  • DarrinNoName

    This Softube Knob is not in my account. I have also refreshed the list. What’s the deal?