If you think I have an obsession with converting mono to stereo, well…you’re right. There are still a lot of mono signal sources around (guitars, mics, vintage synths), but we live in a stereo world.
EQ or delay are the two main ways to convert mono to stereo. The August 17, 2018 tip covered how to use multiband dynamics to create stereo from mono. The December 31, 2020 tip (Super-Simple Mono-to-Stereo Conversion) described something similar but used the splitter, along with a Macro Control panel for added flexibility. The advantage of using EQ for stereo separation (compared to delay) is that if designed properly, there are no phase issues if the stereo is collapsed back to mono.
For delay-based stereo, the August 30, 2019 tip (Widen Your Mono Guitar) works with mono or dual mono tracks, collapses very well to mono, and by using FX Channels, provides a variety of panning and level options. However, the more I used this technique, the more I realized that I kept using the same settings almost all the time. So, it made sense to create a multipreset with fixed settings—then all I had to do was drop it into an insert to provide instant mono-to-stereo conversion. (Note that this isn’t about automatic double-tracking; we have a different technique for that.)
How It Works
This process requires a stereo channel, so set the Channel Mode to stereo (i.e., you’ll see two dots to the right of the input field). However, the audio itself can be mono or dual mono. Fig. 1 shows the FX Chain’s “block diagram.” The Splitter splits into left and right channels.
Figure 1: This multipreset’s simplicity belies its effectiveness.
Each split has an analog delay with identical settings (Fig. 2), except the delay time for one is 11 ms, and for the other, 13 ms.
Figure 2: Delay time settings for the Analog Delays. The only difference between the two is the delay time.
I’ve tested this with guitar, vintage mono combo organ, Minimoog, and other mono sources, including voice. However, it’s not really suitable for bass, which you normally center anyway.
The fixed settings are the best “compromise” settings for collapsing to mono, as well as for creating a stereo image that’s not too spread out (or has an undesired slapback effect). The carefully chosen settings are part of what makes this a “plug-and-play” multipreset. But If you want a wider stereo image, increase the Dry/Wet controls equally for the two delays. You probably don’t want to go much over 50%. You can also increase the 13 ms delay to a higher value but the more you increase the wet level or time, the greater the likelihood that the stereo effect won’t collapse as well into mono.
So, between this and the previous blog posts, I think we’ve pretty much covered mono to stereo conversion—hopefully your guitar or vintage synth will thank you.