Compression is an essential tool for controlling dynamics in a mix. However, overcompression can cause a mix to sound lifeless, harsh, or fatiguing. Here are some signs that your mix may be overcompressed and tips for avoiding it.
What is Compression?
Compression reduces the dynamic range of an audio signal. It attenuates louder sounds and amplifies quieter sounds. This allows you to control peaks, make instruments sit better in a mix, and create a more consistent sound.
A compressor works by setting a threshold. When the signal goes above the threshold, the compressor turns down the volume by a set ratio. For example, a ratio of 4:1 means for every 4dB the signal goes above the threshold, it will only go up 1dB. The more compression you apply, the more the dynamic range is reduced.
Why is Compression Overused?
There are a few reasons compression is often overused:
- It can make instruments sound more powerful and forward in a mix.
- Heavy limiting on the master bus can result in a loud, in-your-face kind of sound.
- Amateur engineers often use compression to fix issues they don’t know how to address otherwise.
- It’s easy to get carried away with compression settings and overdo it.
Additionally, our ears tend to perceive compressed sounds as being better or higher quality at first. But this perception diminishes over time, leaving the mix sounding unnatural.
Signs of an Overcompressed Mix
Here are some telltale signs that a mix has been overcompressed:
1. Excessive Pumping and Breathing
Pumping refers to an unnatural swelling effect caused by a compressor quickly turning the volume up and down. This can make the mix sound like it’s “breathing.” Fast compressor attack and release times exacerbate pumping.
Some pumping can help create groove and energy. But excessive pumping sounds unnatural and distracting.
2. Loss of Transients
Transients provide impact and clarity to sounds. They are the initial spike at the start of notes. Overcompression can flatten out transients, removing the punch from drums and attack from instruments.
Listen for whether your snare and kick still have a crisp snap. Or if sustained sounds like vocals and guitar lack articulation.
3. Harsh and Fatiguing Treble
With overcompression, high frequencies can become exaggerated. This leads to a brittle, harsh, or tinny sound. Instruments with lots of high-end like cymbals, distorted guitar, and synth leads will sound particularly unpleasant.
Too much high-end can cause listening fatigue over time. The excessive treble overwhelms the ears.
4. Loss of Depth and Space
Dynamics help create the sense of depth and space in a mix. Compression can flatten the sound and make it one-dimensional. You lose the sense of instruments sounding near or far.
Listen for whether reverbs and delays now sound disconnected from the dry sound. And if panning sounds unnatural because spaces between instruments are removed.
5. Excessively Loud Master Volume
Over-compressing and limiting on the master bus allows you to crank up the final volume. But this excessive loudness causes fatigue.
Check your mix at low to moderate volumes. If it still sounds good, the master volume is likely fine. If it only sounds good blasting at full volume, it may be over-limited.
6. Bass Losing Punch and Definition
The low end is often heavily compressed to control the sub and bass. But too much compression can make the bass guitar and kick drum become indistinct.
A/B your mix against reference tracks. If the low end lacks punch and sounds muddy compared to the references, it may be overcompressed.
How to Avoid Overcompressing
Here are some tips for using compression effectively and avoiding overcompression:
1. Only Compress When Needed
Use compression only to control specific problems. Don’t default to slapping a compressor on every track.
2. Use Moderate Ratios and Settings
High ratios above 8:1 are usually not needed. Opt for moderate attack and release times. Listen and adjust carefully.
3. Use Multiband Compression
With multiband compression, you can target specific frequency ranges. This avoids excessive compression on the whole signal.
4. Automate the Threshold
Rather than compressing the entire track, use volume automation to control peaks. This maintains dynamics.
5. Use Parallel Compression
With parallel compression, you blend the compressed signal with the original uncompressed sound. This provides control while maintaining dynamics and transients.
6. Use a De-esser Rather Than Compressing Highs
A de-esser will transparently control harsh sibilance and high frequencies instead of compressing the entire signal.
7. compressor shouldn’t be applied to the master bus by default
Rather than automatically putting a compressor on the master, try using it only if needed to control rogue peaks. Limit compressor use to individual tracks instead.
8. Compare Against Quality References
Reference tracks in the same genre help reveal if your mix is overcompressed. Match the apparent depth and impact of the references.
9. Take Breaks and Use Fresh Ears
Compression choices affect how listenable and fatiguing a mix becomes over time. Take frequent breaks to reset your ears.
Advanced Techniques
These advanced techniques can provide more transparent control over dynamics.
1. Optical Compressors
Optical compressors tend to have a smoother, more musical response. Their natural compression can be preferable to the surgical sound of VCA/FET compressors.
2. Variable Mu Compression
Variable Mu compressors have a flexible attack and release responding to the audio. This creates a less obvious compression effect.
3. Expanders
Rather than compress quieter parts, use an expander to lower the noise floor. This increases perceived dynamics.
4. Dynamic EQ
Dynamic EQs allow compressing only narrow bands. You can compress problematic frequencies rather than the whole signal.
5. Serial Compression
Using multiple gentle compressors in series can sound more natural than a single compressor working hard.
Conventional Compressor Plugins
Here are some of the most popular stock compressor plugins included in DAWs:
| DAW | Compressor Plugins |
|---|---|
| Ableton Live | Glue Compressor, Compressor, Multiband Dynamics |
| Logic Pro | Compressor, Adaptive Limiter, Multipressor |
| Pro Tools | Pro Compressor, Pro Limiter, Pro Multiband Dynamics |
| FL Studio | Fruity Compressor, Fruity Multiband Compressor, Fruity Limiter |
Third-Party Compressor Plugins
Here are some popular third-party compressor plugins:
| Plugin | Manufacturer |
|---|---|
| Renaissance Compressor | Waves |
| PuigChild | Waves |
| LA-2A | Universal Audio |
| 1176LN | Universal Audio |
| SSL G-Channel | Waves |
| API 2500 | Waves |
Conclusion
Overcompression is common, but detectable and avoidable. Listen for excessive pumping, loss of transients, harshness, diminished dynamics, and other unnatural effects.
Use compression only when needed. Opt for moderate settings, automate thresholds, and compare your mix against quality reference tracks. Advanced techniques like parallel compression and expanders can increase transparency.
With care and restraint, compression can provide control over dynamics while maintaining the impact, clarity, and life of a mix.