PreSonus Blog

The Ultimate TremPan

I never lost faith in the potential of tremolo, even after those opto-based amplitude processors in guitar amps had become quaint. X-Trem rewarded my faith—and it’s about time tremolo joined the 21st century, given that we’re a fifth of the way through it already.

This FX Chain does dual-band standard tremolo, harmonic tremolo, and panning—and because it’s dual-band, the high and low frequencies are processed independently. You can download the Ultimate TremPan FX Chain if you can’t wait, but because of the flexibility, let’s go through the control panel before covering how it works.

Download the Ultimate TremPan FX Chain!

The control panel (Fig. 1) gives multiple ways to configure the effect. The low- and high-frequency bands have identical switches.


Figure 1: The TremPan control panel.

  • Trem/Pan – chooses tremolo or panning mode
  • Sync – Syncs to tempo
  • Flip – Reverses the LFO phase, e.g., from positive-going to negative-going sawtooth
  • Bypass – Bypasses a band, so you hear the effect on only the non-bypassed band

Let’s look at the controls. The low- and high-frequency bands have three controls in common.

  • Speed – The sync switch determines whether the LFO speed syncs to tempo or runs free. When running free, the Speed control calibration still shows rhythmic values, but it’s actually continuously variable.
  • Depth – Controls how much the tremolo or panning affects the signal.
  • Shape – Available LFO waveforms are Triangle, Sine, Sawtooth, or Square.

The Hi/Lo Mix control determines the balance of the low- and high-frequency bands. Imaging spreads the low and high bands; when centered, the low and high bands are centered too, and if a band is in panning mode, it pans the full stereo field. Turning this control counter-clockwise moves the low band toward the left and the high band toward the right, while de-emphasizing panning so that when fully counter-clockwise, both bands are acting as tremolos in their respective channels. Turning this control clockwise reverse the action, i.e., when fully clockwise, the high band sounds like a tremolo in the left channel, while the low band sounds like a tremolo in the right channel.

How It Works

 Figure 2 shows the block diagram.

Figure 2: The processors inside the Ultimate TremPan FX Chain.

The Splitter does two splits based on frequency, with a split around 800 Hz. This seems to work well for guitar, but feel free to play around with it (I hope that in some future update, Splitter parameters will be assignable to control panel Macro knobs).

The Mixtools have their gains varied oppositely by the Lo/Hi Mix control to set the proportions of the high and low bands. The Dual pans in the Splits have their Input Balance controlled oppositely by the Imaging knob.


You have a lot of options, but here are some of my favorites.

  • Different tremolo speeds and waveforms avoid the stereotyped tremolo sound.
  • For EDM tremolo, try two negative-going sawtooths (i.e., don’t enable Flip) with the low band set to 1/8th notes and the high band set to 16th This gives a cool percussive effect.
  • You can do the “harmonic tremolo” effect, as found in some old Fender amps, by setting both modes to tremolo and the same speed, but choosing Flip for one of the bands.
  • Panning the low band back and forth slowly while setting a fairly fast tremolo for the high band gives a wide, interesting imaging effect.

The rhythmically synched effects can make one instrument almost sound like two instruments, working together as a team. This FX Chain can also animate hand percussion tracks by varying where the percussion happens in the stereo field. Have fun with this sucker—it’s time to re-discover amplitude modulation.