Ambient Guitar Swells Without the $$$ Effects Pedals

I want to make beautiful ambient guitar swells. This classic video tutorial from Andy Othling shows the typical way to achieve this with an electric guitar and a volume pedal. His video is amazing, and the effect sounds beautiful. The only problem is that he’s using several thousand dollars’ worth of guitar pedals.

I wanted to see if I could reproduce that same effect with an acoustic guitar and no pedals, just free software on my laptop. After some trial and error, I’m happy to share this short tutorial to show you how I built this patch in VCV Rack to create a beautiful automatic volume swell for ambient acoustic guitar.

I recorded a quick demo here, and I’ll explain the patch in detail, below.

You can download the patch here.

Stage 1: Automatic Volume Swells

The most important part of this patch is that it needs to cut off the harsh attack for the split-second after you pluck or strum the guitar. It’s a bit like bowing a stringed instrument: the volume starts quietly, gradually swells in, and then gradually fades out. I achieved with this an envelope follower, comparator, ADSR, and VCA.

For this demo, I recorded the input audio sample into the Advanced Sampler, but for playing live guitar, the input signal would normal come directly from my microphone.

  1. The input audio goes to the envelope follower (Bog Audio Follow), which generates a CV output matching the amplitude of the audio signal, with the rapid transients smoothed out (I got good results with smoothing set to 50%).
  2. That CV signal is sent to a comparator (VCV Compare), which generates a gate signal when the input CV exceeds 0.2V (you will need to adjust this voltage depending on the dynamics of your input signal).
  3. That gate signal triggers an envelope generator (VCV ADSR EG), with Attack, Decay, and Release all set to around 400ms, and about 60% Sustain.
  4. That envelope controls a VCA (VCV VCA), which controls the volume for the original audio signal.

The oscilloscope (Count Modula Quad Trace Oscilloscope) illustrates what’s happening: the original audio signal is red, the output of the envelope follower is yellow, the ADSR envelope is green, and the final audio signal is blue.

Stage 2: Polyphonic Octave Generator

To increase the awesomeness of the sound, I take three copies of the Stage 1 output and mix them together: channel 1 is dry, channel 2 adds a sub-octave to the low end, and channel 3 adds an octave-up to the high end.

I’m using the low-pass and high-pass outputs of the built-in filter (VCV VCF) to split the signal, and then routing them through the excellent xVox Harmonic Pitch Shifter to add the octave effects.

Stage 3: Multi-stage Delay & Reverb

Following the example from Andy Othling’s tutorial, the output of Stage 2 is routed into two delays in series (VCV Delay, Chronoblob2) to increase the sustain and add stereo width. Finally, I added a lot of wet reverb (Plateau) to make it sound holy!!!

I enjoy the fully wet signal from Stage 3, but if you prefer to retain some of the acoustic guitar sound, it’s also nice to mix back in a little of the dry signal after the reverb.

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Might I suggest this: :slight_smile:

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nice short tut video :+1:

Airwindows with the Galactic (initial) preset is great too
and if you put 3 or more instances of the airwindows with different presets in a row
you can have a great multiFX for ambient sounds

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Nice! I did this a few years ago, and added some synth pads triggered by the envelope follower and a looper too. The synth voice just plays random notes quantised to a scale, so you have to play in the same key. I think it was sample and hold into the quantiser, the patch is still shared online if you want a look. You don’t need thousands of pounds worth of hipster pedals, VCV is incredible for guitar effects (although I don’t perform live, can understand people preferring hardware for that). Here’s the video, there’s a whole series of these with increasing levels of weirdness/unusable ideas :smile:

EDIT: Wow, thanks for the tip with gregsbrain harmonic pitch shifter, that’s incredible! I must have missed that or assumed it was just for CV, not audio. It tracks really well and can take a few notes at once. Just made a quick patch with four of them, octave up/down, third and a fifth panned around the stereo field. Sounds beautiful and I can’t believe how well it tracks in software. Really impressed because I’ve wanted a decent pitch shifter/harmoniser for years and actually bought a pedal in 2020 because we didn’t have a decent modue in VCV. This is going straight in a few ambient guitar patches! I’m also going to use it in my free shimmer reverb 2.0. Cheers!

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This is beautiful, thanks for introducing me to 57 new rabbit holes :slight_smile:

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Thanks, great job with that tutorial by the way! Some good suggestions in this thread too, Portland Weather and Airwindows are both great for guitar fx. Loads of options in VCV, and modular gives you almost infinite possibilities.

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Oh that was so good. I saw and heard your demo and was thrilled. Of course I downloaded your patch and played around with it. In the end I had my own guitar running in your patch. Had a little feedback from my mixer, but that’s another problem. Really cool.

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O thank you very much. First of all a wonderful patch. In combination with richard’s patch and yours, I have my own guitar running in VCV. BTW I have not touched my guitar for at least 20 years.

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That’s awesome! I was the same, got really into cycling a while back, and started doing bike races and triathlon, and stopped keeping up to date with music tech/production. Hardly played guitar either for years. Then in 2018 I decided to search for some free synth VSTs and just see how things had progressed in the ten years or so I was out of the game, and here we are! As soon as I found VCV I thought it would be cool to process guitar through it. Now it’s a total obsession!

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you’re not alone
:wink: :+1:

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There are far worse obsessions, right? :wink: