Strings and Stereo Widening


Back when I recorded and mixed This is My Father’s World, I mentioned that I used a stereo widener on the string section. I also panned the strings differently from a real orchestra. I’ve been wanting to do this little demonstration ever since then.

TrackingWindowFor this exercise I’ve isolated the string section at the beginning of the final chorus of Father’s World. If you will remember, the strings carry the melody for the first several bars before giving over to the recorder and finally dropping out completely for the hammered dulcimer. You can see from the screen shot, right, the top track is the end of the solo violin recording, and the next three are my Garritan Personal Orchestra string section. I fade out the string section after the violin is done playing in this example.


First the panning: there are different schools of thought about how to pan a digital orchestra. The purists will tell you to pan it exactly like an orchestral string section: from left to right are first violins, seconds, violas, cellos and double basses. Others will say that this seating arrangement is a relic from the past that need not be adhered to in the modern age – do whatever sounds the best to you. Since I’m not striving for authentic orchestral mock-ups, I tend to fall more into the second camp.


Let’s start with something I would never do in real life, just for comparison – mono. Since the solo violin recording is in mono and all the string samples are in mono, this is truly a mono mix. Above is a screenshot of the mix window showing all the channels panned right to the middle.

To the right is a shot of the Flux Stereo Tool, which I used to change the stereo width after setting the panning. The funky round display is a Lissajous display, or goniometer, which shows phase correlation. This will tell you how “stereo” your material is. A straight, vertical line, as shown here, indicates perfectly mono material.

Interestingly, I tried using Flux to widen the stereo image, but apparently it needs some sort of stereo signal to work on, because nothing happened. You will see later on that when you widen an image as much as possible, the line flattens out pretty much horizontally. A perfectly horizontal line would indicate the same audio in each channel, just perfectly out of phase with itself.

Here is the audio from the mono mix:

Orchestral Seating

MixerOrchFluxOrchNoneSecond I set up the panning to reflect a typical orchestral seating layout, as described above. I left the solo violin straight up the middle. The Flux Stereo Tool shows a pleasing tangle of yellow around the center of the display, but is still trending more or less vertical. When the display reaches a perfect circle, that indicates that you have the widest possible stereo width while still retaining mono compatibility (i.e. if you collapse the signal to mono, it will still sound all right). Here is the audio of this:

FluxOrchWideThen, for fun, I smashed the stereo widener to its full extent. The screenshot to the left shows the results: the display shows a practically flat horizontal line. Note that the width control is all the way to 12.00 dB, the maximum setting. As you listen to the audio, below, take note of the artifacts imposed on the audio – it’s definitely wider, but there’s a warble now, and the high material has all but disappeared – the solo violin is pretty much completely gone.

Father’s World Panning

MixerMixFor Father’s World I set the panning up how I wanted to hear it, with a left-to-right balance between the parts. In the mixer window screen shot, left, you can see the panning assignments. The first and second violins are 33% left and right and the violas and cellos are outside them at 66% left and right. I didn’t go 100% with the violas and cellos (or wider with the violins) because it is important to me in this age of listening to everything on earbuds that no individual elements in a mix be panned hard left or right. This is a controversial opinion.

I do think hard panning can sound good on speakers, but it just falls flat to me on headphones/earbuds. Some exceptions are stereo instruments that I want to spread across the entire soundstage,  doubled parts or an extremely busy mix.


The Flux Stereo Tool, right, shows that this panning scheme is not so wide as the orchestral seating. This is to be expected, because if you go back and look, I did pan the extreme parts 100% left and right in the orchestral setup. This time nothing is further out than 66%. This is why I went for a stereo widening tool in the first place – to artificially widen the music. You can hear the results of the straight panning below.

FluxMixWideI listened to the audio and played with the width control until I found something that was just right. You can see from the correlation meter that I pushed the widening to just under 7 dB. The display is just a little flat of circular, meaning that if you played this back in mono you would lose a little information, but not much, and this is where I liked the stereo sound the best.

Here is the audio:

Final Thoughts

Stereo widening can be a powerful tool. If you have very percussive and transient-rich material the smearing may be too counterproductive – I would probably stick with material that is already pretty smooth, such as the string section from this example. I understand that many mastering engineers will apply some subtle stereo widening as part of the mastering process. Again, I think that subtlety and using the most transparent effect you can get your hands on are key.

Flux Stereo Tool is not the only stereo free widener on the market. Blue Cat’s Widening Gain uses mid/side volume controls to increase stereo width. There are also numerous other mid-side processors such as Voxengo’s MSED that can widen the stereo field that way. Jeroen Breebaart’s Omnisone works in much the same way as Flux Stereo Tool, but without some of the extra controls. Quikquak’s Upstereo is a widener with a unique track-ball-like interface. I think in a future post I’ll try a shoot-out between these plug-ins. Stay tuned.

Finally, much of the background for this post is from an article in Sound on Sound magazine by editor Hugh Robjohns: Processing Stereo Audio Files. Worth checking out.

So, go experiment. See what works for you and what doesn’t. And go make some music!

p.s. Please don’t forget, if you have navigated here from my Facebook page and wish to leave a comment, please leave it here and not on Facebook. Thanks!

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