1 Answer
In audio compression, hard knee and soft knee refer to how the compressor reacts to signals that exceed the threshold (the level at which compression starts to apply). Here's a breakdown of the differences:
1. Hard Knee:
Example: Imagine a signal that is a little below the threshold. Once it exceeds the threshold, it gets compressed right away, leading to a more noticeable change in volume.
2. Soft Knee:
Example: With a soft knee, as the signal approaches the threshold, the compressor starts applying a little bit of gain reduction. The closer it gets to the threshold, the more compression is applied, making the transition smoother.
In short:
Soft knee is often used in mastering or when you want to subtly control dynamics, while hard knee is used when you need more aggressive compression.
1. Hard Knee:
- Sharp onset: A hard knee means that the compression kicks in suddenly and sharply as soon as the signal exceeds the threshold.
- Immediate effect: When the input signal crosses the threshold, the compressor applies the set ratio (e.g., 4:1, 2:1) immediately and drastically. This can result in noticeable changes to the sound.
- More noticeable: Because the change is abrupt, the compression effect can be more noticeable, especially on transients (like drum hits or snare sounds).
Example: Imagine a signal that is a little below the threshold. Once it exceeds the threshold, it gets compressed right away, leading to a more noticeable change in volume.
2. Soft Knee:
- Gradual onset: A soft knee means that compression starts gradually as the signal approaches the threshold and gets more intense as the signal continues to rise above it.
- Smooth effect: Instead of an immediate, sharp change, the compressor gently introduces compression. This is less noticeable to the ear and results in a smoother sound.
- More transparent: Itβs often used when you want the compression to be more natural and subtle, so the effect is not as obvious.
Example: With a soft knee, as the signal approaches the threshold, the compressor starts applying a little bit of gain reduction. The closer it gets to the threshold, the more compression is applied, making the transition smoother.
In short:
- Hard knee: Sudden and noticeable compression once the signal exceeds the threshold.
- Soft knee: Gradual compression, making the effect smoother and less noticeable.
Soft knee is often used in mastering or when you want to subtly control dynamics, while hard knee is used when you need more aggressive compression.