What’s wrong with transient shapers?
Transient shapers are processors that adjust the dynamics of a sound. Rather than changing the dynamic range like a compressor, transient shapers operate only on the initial onset of the sound – the transient. The initial smack of a drum. The plink of a piano. The pick of a guitar or bass. They don’t work with sounds that don’t have a sudden start, such as vocals, violins, or synth pads. Transient shapers can either bring out the transient – making it louder, sharper and more prominent. They can also reduce the transient – making it softer and duller.
The tricky aspect to consider here is that the psychoacoustic (perceived) effects of a transient shaper can be similar to those of other tools.
For example, both EQ and compression can also be used to make a sound sharper or duller. Depending on the tone and envelope of the sound, an EQ or compressor can also be used to enhance or reduce the transients. They certainly can be used to make sounds more or less prominent.
In fact, for most day-to-day mixing tasks, channel EQ and compression offer almost all the sound shaping tools you need.
So why use a transient shaper?
If you only want to adjust the transient, EQ and compressors are blunt tools. Using a static EQ setting to boost the upper mids might bring out the ‘pluck’ of a guitar or ‘smack’ of a drum, but it will make the whole sound brighter. Similarly, using a compressor to adjust a transient will also affect the decay and/or sustain of the sound as well. Compressors are also level-dependent, meaning they process individual notes differently depending on how loud they are. This means that a dynamic performance will be treated unevenly – which is exactly what you want if you’re trying to control the dynamics, but not desirable if you’re trying to control the transients.
A transient shaper, by contrast, will process the sound while keeping its tone and dynamic behaviour intact. Most good transient shapers also operate independently of level, meaning they should apply the same amount of change to the transient, regardless of how loud or soft the sound is. Transient shapers are a subtle tool, and are best used when regular EQ and compression tools are unable to be subtle enough.
As always, a clear understanding of your tools will help you create the sound you’re imagining.