Hi,

I recently experimented with a technique for adding a stereo component to one or more mono signals.
It doesn't require any special plugins or tools, just a little routing and a DAW that allows the use of feedback loops.

If you'd like to try this technique, here's the recipe:

- Send your mono track(s) to a mono auxiliary track, which we'll call "FEED" for the example.
- Cut the send to the master of this "FEED" track, and send it to two other mono auxiliary tracks, which we'll call "LEFT" and "RIGHT" for the example.
- Pan the "LEFT" track all the way to the left
- Pan the "RIGHT" track all the way to the right
- Reverse the polarity of the "RIGHT" track (very important)
- Sum the "LEFT" and "RIGHT" tracks into a fourth stereo auxiliary track, which we'll call "SPREAD" for the example
- Finally, create a pre-fader send from the "SPREAD" track back to the "FEED" track.

The very short delay induced by the feedback loop, coupled with the polarity reversal of the "RIGHT" track, will create the desired effect.
Then adjust the amount as desired using the "SPREAD" track fader, or using the sends from the mono tracks to the "FEED" track.
You'll also notice that this technique only adds a side component, which will completely cancel each other out on a mono monitoring system.

Since this technique relies on the use of a feedback loop, I recommend placing a brickwall limiter or other overload protection system just before your monitoring output, just in case. It's not essential, but it can protect your equipment and, more importantly, your ears in the event of mishandling.

You can also add processing of your choice. For example, a high-pass filter on the "FEED" track can be a good idea to preserve the low frequencies of the effect.

If you use Reaper like me, I've developed a Lua script that makes setting up this system easier, and you can download it freely here :

https://forum.cockos.com/showthread.php?t=302332

or here :

https://stash.reaper.fm/v/50514/Studio Kozak - Feedback Stereo Spread.lua

Ableton Live, Logic Pro, and Pro Tools also allow the use of feedback loops internally. However, Cubase or FL Studio users will have to bypass the permanent protections implemented by Steinberg and Image-Line if they want to try this technique. For other DAWs, I refer you to their user manuals.

There are, of course, other ways and techniques for adding a fake stereo effect.
But this one is particularly elegant, isn't it ?

 

Not the best word to describe me... I just haas that thing. Really rude, i'd say.

 

Or you can go the scientific way (wikipedia Duplex Theory) and use modern tools. Ozone Imager, 2 instances in series, both set to 10ms: first instance up to 1.5 kHz Stereoize Mode I, applies Haas. Our ear is more sensitive to time differences in the lower-mids. Second instance from 1.5 kHz and above Stereoize Mode II, applies decorrelated noise (randomly modulated level differences between channels, avoids comb effects). Our ear is more sensitive to level differences for higher frequencies.

This configuration will produce a perfectly mono-compatible pseudo-stereo output with virtually no audible comb-filtering side-effects. The hybrid filters in Ozone Imager have little to no impact on the phase of the incoming signal as well.

 

I am a heavy user of the vescoFx Freehaas vst plugin pretty simple to use and it's free.
https://www.kvraudio.com/product/freehaas-by-vescofx

It allows you to take a stereo source and expand it to the sides which makes for some interesting effect ( Michael Jackson's billy jean for example)

For Mono Stereo I just take the same mono file and add it to another track and add some small amount of Stereo delay.

Sending that original track to another one with Reverb and bringing down the dry signal on the reverb etc can make some interesting results.

 

Last edited: Aug 13, 2025 at 3:11 AM

Have you ever used Arx vst?
https://www.kvraudio.com/product/arx-one-by-zone-sk

 

Negative.

 

The Beetles trick

0) Duplicate mono track

1) first panned 100% left

2) second panned 100% Right

3) Apply subtle reverb on 2)

4) Apply audible reverb on 1)

Play

P.S.
Use same kind of reverb, try Plate first 'cause is easy to setup

 

Last edited: Aug 13, 2025 at 10:44 PM