NGWave Audio/Sound/MP3 Editor: Compression Part III

This is a continuation of our compression tutorial.

More on the Side-Chain

Another use for this concept is known as de-essing. Essing is the term for when high-frequency sounds -- such as that made when pronouncing the letter 'S' -- are distorted. Often Compression can lead to Essing, as sometimes compressors aren't as sensitive to higher frequencies. This can be corrected with a side-chain filter that increases really high frequencies, to increase the compressor's response to these frequencies.

The only way to truly get the best possible compression response is to use an Equalizer on the Side Chain in a physical comrpessor. This lets you tweak exactly how each frequency band affects the compression levels, and gives complete and total control over the response.

Note that with digital compression, essing isn't usually a problem; the mathematics for digital compression aren't inherently frequency-dependant.

NGWave offers a Side Chain filter, reducing low frequencies (around 200 Hz) by 6db before entering the Side Chain, to help with the Pumping problem. A full Side Chain EQ will appear in a future version of NGWave.

Enhancer

Different brands of dynamic compressors have different names for this particular feature, but the Enhancer simply increases the high-frequency response in the output, depending on how much compression is applied. The more compression, the more treble boost. This helps to further reduce the Pumping effect, because as more compression is applied, your higher frequency audio is increased slightly, making up for the volume drop.

It also helps to reduce the effect where high frequencies tend to be drowned out when compression is applied. This is typically seen with faster attack and release rates.

NGWave offers an Enhance feature, offering up to about 12 db of extra treble response during heavy compression.

The Digital Age

As we continue on in the so-called "Digital Age", we see many things replicated in the digital domain. Sound editing itself is one such development. Offering real-world features in digital form is another.

NGWave's Dynamic Compressor attempts to, as much as possible, mimic the operation of a real transistorized compression unit. It offers many of the same features, as well as Oversampling (specific to digital devices, but intends to smooth the compression curve as much as possible). NGWave offers a Soft-Knee curve with three internal soft thresholds, a Hard Clip feature, and more.

Other editors attempt to replicate true dynamic compression, but usually fail quite miserably once you try to use it in a real-world application. Controlling the overall volume of a song, or decreasing the dynamic range of an older recording, for example, prove to be futile in the typical sound editor.

NGWave's compression is as good as an average transistorized compressor, and sometimes better (for example, being digital, it adds no noise to the signal at all). If you've used compression for drum or guitar effects, NGWave will perform like no other. The author personally uses NGWave along side two Behringer analog units (which NGWave's compression was modeled after), and frequently finds better results from NGWave...

If you are an audio professional and can think of ways to improve NGWave's Dynamic Compression, please email  Suggestions@NGWave.com.

Coming Soon to NGWave: Multiband Compression (as well as a followup article on the same topic).

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