Monday, August 6, 2012

Gaining the Illusion of Width in a Stereo Mix

 Finding the limits of width

To gain great perspective upon the width possible within a stereo mix, take your stereo speaker setup (which you hopefully have positioned ideally for a good stereo image) and switch the polarity of one of the speakers.  That is, take the + and - wire on ONE speaker and switch it.  This will put the speakers out of phase with each other.  Basically, as one side projects a wave out, one side pulls a wave in (compresses/decompresses).  Also make sure any processing/subwoofers/additional speakers are turned off.

It is also possible to separate a stereo recording to 2 mono tracks - pan them hard left/right and invert the phase of one track to achieve the same results.

Play material that has otherwise a very solid center image - say an intimate vocal recording or perhaps even AM radio - the once center image will now appear to come from as far left and right as your speakers will allow you to perceive.  You may also notice significantly reduced bass response.  Switch phasing back and forth with various program material to hear the whole of differences.

Its possible your speakers were out of phase previously, and switching one now puts the image in the center/improves bass response.  This is a very common problem that many people don't realize.

This should present you with a very clear idea of what is possible regarding the width of your productions.  Beware, though, 2 tracks out of phase will cancel eachother out entirely when summed to mono.


Wikipedia explains the phaser effect as
"The electronic phasing effect is created by splitting an audio signal into two paths. One path treats the signal with an all-pass filter, which preserves the amplitude of the original signal and alters the phase. The amount of change in phase depends on the frequency. When signals from the two paths are mixed, the frequencies that are out of phase will cancel each other out, creating the phaser's characteristic notches. Changing the mix ratio changes the depth of the notches; the deepest notches occur when the mix ratio is 50%"

The best way to understand a phaser is to just use one.  Any DAW will have a phaser plugin, just mess with the settings.  Often the plugin will have a "width" setting that will get the ball rolling on widening your sound.

Multiple phasers can be layered to create some really wild effects, but phasers can also be used in a subtle way to add interest and "phatten" a sound.


 In your DAW record a mono track - the track can be any sort of melody/rhythm.   Now duplicate the mono track.  Grab the audio file on the duplicated track and scoot it over a bit so it begins playing a bit after the original track.  Duplicate this track yet again and repeat the process so all 3 tracks begin at different times.

Now, the track that begins first keep panned center - the other 2 pan one hard left one hard right.  When you press play on the transport you will hear the illusion of a space, something akin to a reverb sound.

This is just the tip of the iceberg regarding delay and the illusion of width.  Delay plugins can be used on 3 seperate tracks to take the above example yet further.  Include feedback/saturation/filtering and even phasing and an otherwise mono signal can appear to be emanating from a swirling and mesmerizing space.


Reverb is perhaps the most common thing folks go to when they want to create the illusion of a space.  Some reverbs are better than others - and while all sounds can certainly be used creatively - when it comes to truly giving the illusion of a space the one reverb that does it best is convolution.

Convolution reverb plugins use impulses (a gunshot, clap, etc recorded in a space) and utilize the information to create a very realistic replication of the properties of the space.  There are many fine plugins that will be reviewed here in time.

Reverb would appear to be a "one stop shop' when it comes to creating a space, but its really not.  Reverb can muddy up a track - similarly to how actually playing certain things in a concert hall will create a muddy mosh of reflections that make no sense.  Reverb mud is compounded yet still if the system reproducing the sound is in a space that has alot of natural reverb!

Reverb certainly has its place, but it must be used carefully.  A trick I like to use is to mix the reverb in mono - it becomes easier to hear if things are getting muddy when all the reflections are literally on top of eachother.


Chorus alters the pitch and introduces a bit of delay on the altered signal - in order to simulate the natural variations that occur when a human tries to create the same sound twice.  When mixed in with the dry signal some really interesting things happen. , and many plugins will offer a "width" or "spread" function, which can add some great width to the sound.  If not, a mono chorus can be panned hard left, and another hard right to produce a similar (and truly more controllable) effect.

Chorus with the addition of a phaser can get very interesting, but of course it mixes well with many techniques.


Wikipedia has a great explanation:
"Flanging is an audio effect produced by mixing two identical signals together, with one signal delayed by a small and gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and notches are produced in the resultant frequency spectrum, related to each other in a linear harmonic series. Varying the time delay causes these to sweep up and down the frequency spectrum. A flanger is an effects unit dedicated to creating this sound effect."

A flanger produces something relatively similar to a phaser effect, and is similarly interchangeable.

Mid Side

A method that can be used in conjunction with any/all of the above is to encode the audio in Mid/Side (rescue is free and does a great job).  Once the audio is in mid side (assuming its a stereo recording), the levels of the middle and side information can be adjusted to create the illusion of the source being farther away than it truly is.

Mid side processing has many uses, used with a reverb it can help keep the center clear while still offering the sides plenty of spaciousness - again this is best checked with mono.  Delay generally does not benefit from mid/side encoding, but it depends on how you are laying out your track.  Phasing and mid side can yield some very interesting effects indeed.  Compressing the sides seperate from the middle is another great width adding technique.


Automating the parameters of any/all of the above will truly create a unique space that does not muddy up.  Bringing in reverb at the tail of a sound (particularly a long vocal note) while cutting it down for the attack part of the sounds works wonders.  Manual pan automation opens up alot of possibilities as well, autopans can be more rhythmically accurate and easier to manage but they are not always the way to go.

Automation is the key to making a section really get BIG, or small, whatever is required.  Big width on a chorus is a typical technique - backing vocals also benefit greatly from the aforementioned methods.  Automation allows for temporarily muddy parts that can be cleared up to polarize dryer spaces and make each yet more appreciated.

Have fun trying the above techniques by themselves and in combination, they will certainly add that 3 dimensional sound you have been looking for!

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