PreSonus Blog

Friday Tips: The Best Flanger Plug-In?

Well…maybe it actually is, and we’ll cover both positive and negative flanging (there’s a link to download multipresets for both options). Both do true, through-zero flanging, which sounds like the vintage, tape-based flanging sound from the late 60s.

The basis of this is—surprise!—our old friend the Autofilter (see the Friday Tip for June 17, Studio One’s Secret Equalizer, for information on using its unusual filter responses for sound design). The more I use that sucker, the more uses I find for it. I’m hoping there’s a dishwashing module in there somewhere…meanwhile, for this tip we’ll use the Comb filter.

Positive Flanging

Figure 1: When set properly, the Autofilter’s comb filter can make a superb flanger.

Flanging depended on two signals playing against each other, with the time delay of one varying while the other stayed constant. Positive flanging was the result of the two signals being in phase. This gave a zinging, resonant type of flanging sound.

Fig. 1 shows the control settings for positive flanging. Turn Auto Gain off, Mix to 100%, and set both pairs of Env and LFO sliders to 0. Adding Drive gives a little saturation for more of a vintage tape sound (or follow the May 31 tip, In Praise of Saturation, for an alternate tape sound option). Resonance is to taste, but the setting shown above is a good place to start. The Gain control setting of 3 dB isn’t essential, but compensates for a volume loss when enabling/bypassing the FX Chain.


Varying the Cutoff controls the flanging effect. We won’t use the Autofilter’s LFO, because real tape flanging didn’t use an LFO—you controlled it by hand. Controlling the flanging process was always inexact due to tape recorder motor inertia, so a better strategy is to automate the Cutoff parameter, and create an automation curve that approximates the way flanging really varied (Fig. 2)—which was most definitely not a sine or triangle wave. A major advantage of creating an automation curve is that we can make sure that the flanging follows the music in the most fitting way.

Figure 2: The Cutoff frequency automation curve used for the audio examples.

Negative Flanging

Throwing one of the two signals used to create flanging out of phase gave negative flanging, which had a hollower, “sucking” kind of sound. Also, when the variable speed tape caught up with and matched the reference tape, the signal canceled briefly due to being out of phase. It’s a little more difficult to create negative flanging, but here’s how to do it.

  1. Set up flanging as shown in the previous example, and then Duplicate Track (Complete), including the Autofilter.
  2. Turn Resonance all the way down in both Autofilters (original and duplicated track). This is important to obtain the maximum negative flanging effect. Because of the cancellation due to the two audio paths being out of phase, there’s a level drop when flanging. You can compensate by turning up both Autofilters’ Gain controls to exactly 6.00 dB (they need to be identical). This gain increase isn’t strictly necessary, but helps maintain levels between the enabled and bypassed states of the Negative Flanging FX Chain.
  3. In the duplicated track’s Autofilter, turn off the Autofilter’s Automation Read, and turn Cutoff up all the way (Fig. 3).



Figure 3: Settings for the duplicated track’s Autofilter.

  1. Insert a Mixtool after the Autofilter in the duplicated track, and enable both Invert Left and Invert Right (Fig. 4). This throws the duplicated track out of phase.



Figure 4: Mixtool settings for the duplicated track.

  1. Temporarily bypass both Autofilters (in the original and duplicated tracks). Start playback, and you should hear nothing because the two tracks cancel. If you want to make sure, vary one of the track faders to see if you hear anything, then restore the fader to its previous position.
  2. Re-enable both Autofilters, and program your Cutoff automation for the original track (the duplicated track shouldn’t have automation). Note that if you mute the duplicate track, or bring down its fader, the sound will be positive flanging (although with less level than negative flanging, because you don’t have two tracks playing at once).


So is this the best flanger plug-in ever? Well if not, it’s pretty close…listen to the audio examples, and see what you think.



Both examples are adapted/excerpted from the song All Over Again (Every Day).


The Multipresets

If you like what you hear, download the multipresets. There are individual ones for Positive Flanging and Negative Flanging. To automate the Flange Freq knob, right-click on it and choose Edit Knob 1 Automation. This overlays an automation envelope on the track that you can edit as desired to control the flanging.


Download the Positive Flanging Multipresets Here! 


Download the Negative Flanging Multipresets Here! 


And here’s a fine point for the rocket scientists in the crowd. Although most flangers do flanging by delaying one signal compared to another, most delays can’t go all the way up to 0 ms of delay, which is crucial for through-zero flanging where the two signals cancel at the negative flanging’s peak. The usual workaround is to delay the dry signal somewhat, for example by 1 ms, so if the minimum delay time for the processed signal is 1 ms, the two will be identical and cancel. The advantage of using the comb filter approach is that there’s no need to add any delay to the dry signal, yet they can still cancel at the peak of the flanging.

Finally, I’d like to mention my latest eBook—More Than Compressors – The Complete Guide to Dynamics in Studio One. It’s the follow-up to the book How to Record and Mix Great Vocals in Studio One. The new book is 146 pages, covers all aspects of dynamics (not just the signal processors), and is available as a download for $9.99.