Music Production Techniques, Part 5: Expanders, Exciters And Enhancers

Part 5 of this series on music production techniques explores the less celebrated, but still crucial, mixing tools available: expanders, exciters and enhancers. These can make a good mix, great!  

Other Articles in this series:

Part 1, Delay & Echo:

Part 2, Modulation Effects:

Part 3, Distortion:

Part 4, Equalizers & Filters:

Audio enhancement is by no means an essential process and is seen by some as a bit of a gimmick. In some situations however enhancers and exciters can be just what’s needed to inject life into dull, lackluster audio.

Here we’ll take a look at the different kinds of enhancer that are out there and how we can use them to give our badly recorded audio a fighting chance... 


Types Of Enhancement 

I’m actually going to be taking a look at three different kinds of enhancer here. These three types of processor work on three very different areas of our audio: frequency, stereo width and loudness. 

There are some one-stop solutions that offer all of these things in one handy plug-in. I’ll actually be using some of these plug-ins to demonstrate each process we are looking at here. I’ll also look at stand alone products that specialize in one specific area.

Helpfully by the end of the piece you will understand the difference between the different enhancement methods available to us and how you can use them to improve your own mix. 


Exciters And Psychoacoustic Processors 

I’ll start with what is probably considered the most traditional of all enhancement types the ‘Exciter’. The Exciter has been around in one form or another since the mid ’70s when Aphex introduced their ‘Aural Exciter’ unit. 

The Aural Exciter enhanced clarity and added sparkle to any sound by using phase shift and synthesized harmonics. This was pretty groundbreaking stuff at the time and the process was soon adopted a number of top recording artists. 

One of the earliest valve driven units has been reproduced in digital form by Waves and has received the stamp of approval from Aphex themselves. These early units were very simple and only had a few controls.

Waves have modeled one of the earliest exciters to have been manufactured.

Waves have modeled one of the earliest exciters to have been manufactured.


Some dry audio in much need of some excitement:

The same loop treated with the Aphex valve exciter:

Later units introduced something called ‘Big Bottom’ which was a process designed to enhance low end and subharmonics. This process has been recreated by companies such as BBE, SPL, Tone2 and Waves in a number of different hardware and plug-in based products.

A more modern hardware Aphex Exciter.

A more modern hardware Aphex Exciter.


Audio exciters are often referred to as Psychoacoustic processing. This type of treatment promises to add a perceived low or high end enhancement without effecting dynamics or level. 

This can be extremely useful for boosting a specific frequency range without clipping your mix. A live sound engineer may find this extremely useful for boosting the low end of his overall sound without applying any extra pressure to the system’s amps.

One of BBE’s excellent Exciter plug-ins.

One of BBE’s excellent Exciter plug-ins.


The loop treated with a more contemporary BBE process:

These processors can be extremely useful for injecting life into dull or badly recorded audio, or even samples that just need a helping hand. Often exciters are a great alternative to equalization as opposed to a replacement.


Stereo Expanders

Spatial enhancement can be just as useful. If you need a sound to stand out in the mix a little adding spatial effects and increasing its stereo width is a tried and tested winner. The only problem here is that spatial effects can often reduce clarity and effect the audio’s overall impact.

Stereo delays, reverb and modulation effects are classic ways of increasing stereo width but we can use dedicated stereo enhancement tools for a more coherent result. But of course as with any enhancement there are some possible drawbacks. 

Because stereo enhancers often work by manipulating a signals phase characteristics, there can be potential issues with mono compatibility. When using these plug-ins, it’s always a good idea to check if your audio plays back in mono, without elements disappearing or sounding drastically different.

Tone2 AkustiX is an excellent enhancement suite with stereo widener.

Tone2 AkustiX is an excellent enhancement suite with stereo widener.


Some audio without stereo enhancement:

... And now with AkustiX stereo treatment:

Another thing to look out for is how the process effects your low frequencies. Many enhancers simply effect the entire frequency range and can create a confused low end mix, others however will allow you to only effect the upper frequencies.

iZotope Ozone 5’s stereo enhancer.

iZotope Ozone 5’s stereo enhancer.

There are not quite as many stereo enhancers around compared the amount of exciters available in plug-in form, but there is still a decent choice. You might want to opt for a suite of processors such as Ozone or Tone2’s AkustiX

Some DAWs also include stereo enhancers as standard, such as Reason’s Stereo Imager and Logic’s Stereo Spread plug-in.

Logic’s Stereo Spread effect allows lower frequencies to remain in mono.

Logic’s Stereo Spread effect allows lower frequencies to remain in mono.


Loudness Enhancers

You might find that at some point you want to boost the perceived loudness or your audio, your immediate reaction may be to reach for a limiter or maximizer, but in some situations this may not be the best tool for the job. 

The only real problem with heavy limiting and other traditional dynamics processors is that while they reduce dynamic range they also reduce the apparent impact of dynamics and transients. 

One solution is to use a loudness based enhancer, now there really aren’t many of these processors about but a few companies do make them. A good example would be the Sonnox ‘Inflator’.

The Sonnox Inflator.

The Sonnox Inflator.


The Inflator may look like any other limiter but it actually claims to be able to increase your audio’s apparent volume without adversely effecting dynamics. A bold claim and it does work to some extent. There are a few examples below, so make up your own mind!

A guitar loop that could do with a loudness boost:

The Inflator boosts the guitar’s volume while leaving its transients intact:


One Knob Solutions 

Finally if you are somewhat of a beginner and find all these options a little much, you could opt for a more simple processor. There are a good number of enhancers that offer a single control approach to improving your audio.

Waves actually supply an entire range of plug-ins that use this single control philosophy and surprisingly they are called ‘One Knob’. Below you can see a shot of a few of them, each plug-in has a specific purpose and one huge control. It really doesn’t get any more simple than that. 

The Waves ‘One Knob’ series.

The Waves ‘One Knob’ series.


Whether you need to widen your sound, make it louder or simply add sheen and sparkle you should have no problem finding something now you know exactly what enhancement is all about!

TC Electronic’s Character plug-in runs on the TC Powercore platform.

TC Electronic’s Character plug-in runs on the TC Powercore platform.

 Stay tuned. Next Sunday we'll bring you part 6 in this series...

Want to learn more about mixing tools? Join the Ask.Audio Academy HERE.

Mo has been a professional in the music industry for around 15 years. He has released material with the world's leading record labels and also produces music for TV and Film. Mo is also a prolific writer and is a regular contributor to magazines such as Music Tech, Future Music and EQ magazine. There isn't a piece of music software tha... Read More


Want to join the discussion?

Create an account or login to get started!