Dry / Wet Anomalies of a few Ableton Live Effects

Often, plugins will cause an effect they don’t tell you about, and you may not realize is occurring.

Knowing exactly what is happening to audio is valuable, because otherwise if we set up chains of effects we may think that we are resulting in a more transparent sound than we really are. Subtle changes to sound can stack up and add to quite audible differences—which if we don’t know the sources of may be difficult to diagnose and address.

Here’s an overview of some of the things some of Ableton Live’s stock effects do to sound passing through them, which you may not realize at first. Some of these quirks many of you will have gotten to know by ear already just by using the effects, in which case seeing the analysis graphs can provide some “aha” moments.

Dynamic Tube: DC Filter & HQ Mode Oddity

Did You Know? Dynamic Tube provides a built-in DC filter, cutting out a bit of the very lowest frequencies. Its contour is pretty much identical to Utility‘s DC Filter.

Did You Also Know? The anti-aliasing filter of Dynamic Tube‘s Hi-Quality mode has imperfect dry/wet summing, so that if you use a partial setting (anything but zero or 100 percent) it implements a sample-rate dependent upper-frequency dip.
When using Dynamic Tube for hefty distortion, it might be better to enable Hi-Quality mode to avoid aliasing. However, for more clean, subtle, or technical usage of Dynamic Tube, leaving it off might provide better results.

Dynamic Tube, 44.1k 100% Wet (HQ OFF).

Dynamic Tube, HQ Mode, 44.1k 100% Wet.

Dynamic Tube, HQ Mode, 44.1k 50% Wet.
Notice the Dip around 12k.

Dynamic Tube, HQ Mode, 44.1k 25% Wet.

Dynamic Tube, HQ Mode, 88.2k 50% Wet.
Notice the high dip is now higher, around 24k.

And for reference, here’s Utility‘s DC Filter.

Note that the three tube models (A, B, & C) all have this same quirk, although model C also has an overall gain boost of approximately 0.2dB compared to A & B.

Secret Trick: Use the dry/wet knob of an instance of Dynamic Tube at its cleanest possible settings (making sure HQ mode is off), to provide a DC Filter that is controllable in intensity (unlike Utility‘s DC Filter). The free PerforModule Sweetie Pies pack has a rack with this functionality…

Erosion: HF Cut

Did You Know? Working at 44.1k, Erosion causes a steep loss of high-frequency, even with its Amount set to zero. However, this is sample-rate dependent, and simply doesn’t exist at higher sample rates. Even going up to 48k, it disappears and you get a flat curve. Strange!

Erosion at 44.1k, Amount: 0.

Erosion at 48k (or higher), Amount: 0.

Erosion at 22.05k, Amount: 0.
Does anybody even use 22.05k?

Saturator: HQ Mode Filter Thing Again

Saturator appears to implement the exact same “Hi-Quality” anti-aliasing filter that Dynamic Tube does, as it causes the exact same high-frequency softening when using partial dry/wet amounts in HQ mode. So the same advice applies: be aware of the possibility of this, and if you want to make sure that your high frequencies don’t get dampened by automating Saturator‘s Dry/Wet Control, try setting Hi-Quality mode to off.

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The Moral of This Story

There are two obvious takeaways here:

• If using either Dynamic Tube or Saturator‘s Dry/Wet control, switch off “high-quality” mode for a more neutral and expected frequency response.

• If using Erosion in 44.1kHz projects, keep in mind that it will roll off the highs, but in projects at higher sample rates, it won’t.

~`~

These quirks are not necessarily “runkillers”, but it’s always good to be aware when the frequency spectrum is getting fudged with. Above all else, use your ears.

That’s all.
But not all! There are some more quirky anomalies of other types in some of Live’s other effects (not to mention various VST plugins) which might get covered in a future post.

~`~

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