Every violinist who's ever played amplified has had someone tell them they can't hear them half of the time. When we're playing at full volume, we can be heard, but when we're blending with the ensemble, it's harder. Compression may be the answer! In the video below, we explain what compression is, what the key parameters are, how to use compression to get a good sound, and some of the common pitfalls and mistakes people make with compression.
What Is Compression
Compression is a volume effect that compresses your dynamics into a smaller, more manageable range. It is used both to reduce your loudness and to increase your quietness, squeezing your dynamics into a tighter range.
Compression Parameters
- Threshold: The decibel level at which the compressor engages
- Ratio: The amount of reduction applied to the signal above the given threshold, expressed as a ratio. A ratio of 1:1 means no compression is applied. A ratio of 2:1 means that loudness increases at half the rate above the threshold. A ratio of 4:1 means taht loudness increases at a quarter the rate above the threshold. The bigger the ratio, the more compressed the volume is above the threshold.
- Make-up: the amount of gain you want added to the signal after gain reduction is applied. By adding compression, you reduce your gain (above the threshold), so if you want to keep the dynamic smoothing benefit of the compression without being too queit, you need to add gain back in.
- Knee: How your signal behaves as you approach the threshold is determined by the 'knee' setting. A hard knee means that nothing will happen to your signal until it hits the threshold, but as soon as it does it will immediately apply the full ratio of compression. This can result in a compression effect that is audible. If you can hear the compression taking place as you move through the threshold, softening the knee will smooth out that transition by applying it gradually before and after the threshold.
- Attack: Sets a delay between when you exceed the threshold and when compression is applied. A fast attack setting will apply compression very quickly, and a slow attack setting will delay the onset of compression. If you are trying to remove the transients from bow changes, use a fast attack. If you want signal compression but do not want to lose the sound of bow changes, use a slower attack setting.
- Release: Sets a delay between when you fall below the threshold and when compression disengages.
If you have uneven volume levels from bow changes or unwanted hard attacks, applying compression to your signal can reduce those loudest sounds to something closer to the rest of your playing, making them stand out less. If your bow changes produce popping that doesn't belong in your signal, applying a compressor with high threshold and ratio can reduce those transients considerably without affecting the rest of your playing too much.
Pros and Cons of Compression
Pros:
- Smooths out uneven playing
- Tames unwanted peaks and transients
- Can thicken tone and remove harshness
- Keeps you afloat in a band mix by keeping your volume levels up even when you're laying back
Cons:
- Loss of dynamic contrast through over-compression
- While it doesn't cause feedback, it can make feedback worse by raising the levels of problematic frequencies
When To Use Compression
You may not need compression at all in solo performance. In live performance with a band, the FOH (Front of House sound engineer) will typically add compression to your channel for you.
It is helpful to apply compression before certain effects with loud peaks and low troughs, for example Wah and Autowah effects, in order to make the troughs more audible and the peaks less shocking in contrast.
For performance, you can use a compressor stomp box pedal and place it early in your chain (typically after preamp and EQ) or apply compression to virtual effects chains in a multi-effects processor.
In recording, compression can be applied to individual channels in your DAW, which can help with balance issues to avoid more drastic mixing. Compression is particularly useful in the mastering stage to raise the presence and power of an entire track while containing the overall loudness within a useable range.
