Audio Compression Tips for Church Sound
Compression is a great tool that can tighten up your mix and enhance the punch or power of certain instruments. But it can also cause some serious problems if you’re not careful.
An audio compressor is used to control the dynamic range of an audio signal, or the difference between the highest and lowest volume level.
Controlling the dynamic range can help you create a more stable sounding mix (especially when it comes to the pastor’s mic), and you’ll be able to dial in the sweet spot for certain instruments (like the kick drum).
Before we get to some general tips to help you dial in the right sound, it will be helpful to describe what bad compression sounds like so you can avoid it.
The Sound of Bad Compression
Yes, you can over compress something. This often results in a very flat sounding mix, especially if a compressor is connected to the main output or a subgroup. (While this can be ok for a live streaming output or recording, it’s generally not ideal for live reinforcement in the room.)
Improper “attack” and “release” settings can cause the compressor to pump or breathe, making the audio sound unnatural. And you can even compress things to the point where loud parts sound too quite or soft parts sound too loud. Probably not a desired effect!
Good compression should tighten up a mix, give added presence to various instruments and maintain clarity for your vocals.
Good Compression Starting Points
If you aren’t yet familiar with common compression terms like Threshold, Ratio, Attack, Release, Knee, and Makeup Gain, then I recommend checking out this Twelve:Thirty Media blog post that covers the fundamentals of Compression 101
Setting your threshold on the compressor is an important step in determining exactly when the compressor starts to work or not. The signal level that goes above the threshold gets compressed, the signal below the threshold is not affected.
A compression ratio of 2:1 is a good starting point for most vocals, but feel free to bump this up a few clicks if you need to really control the dynamics or presence. I’ve used a compression of 4:1 or even 6:1 on some pastor’s mics due to the wide dynamic range of their speaking style and volume. Try applying a soft compression of 2:1 or 3:1 for acoustic guitars, and use a longer release time to soften out the effect of the compressor.
Most electric guitars will have effects applied from the guitar pedals or processor, so I rarely apply compression to them.
Bass guitars can sometimes benefit from compression, especially if the bass is played with a slap style. Try a 3:1 ratio with a fast attack to control any strong plucking sounds. The average kick drum can benefit from a tight compression somewhere around 4:1 with a fast attack and fast release. Use a 3:1 ratio on the snare with a fast attack and medium-slow release time.
Compare Your Mix
When it comes to practicing with compression, the bypass button can be you best friend. Use this to A/B your compression settings and make sure they are making the positive difference you intend.
Spend some focused time working with your compressor settings, practicing with different instruments and vocals, and critically listening to the difference it makes in your mix.
If all of those numbers and settings seem a little confusing, that’s ok. Just experiment with different settings and even use factory presets to help you get started.
Remember, it’s what sounds good in the final mix that counts!
Author / Audio Engineer
Great Church Sound | Missoula, MT
James Wasem has been fascinated by sound and electricity from an early age. His love of music and technical gear made sound engineering and systems integration a natural pursuit. James has spent the last 20 years performing and touring in bands as a drummer, mixing live sound for churches, schools and theatres, and working as an audio systems installer and designer.
Though involved in highly technical fields, James has a passion for making things simple to understand and easy to use. It was from this passion that the book Great Church Sound – a guide for the volunteer was born. James believes that technical ministry volunteers provide a critical service for their congregations and should be well equipped with quality tools to help them grow in craft, skill, and spirit.
James and his wife Kate (who also provided the illustrations for Great Church Sound) live in the beautiful Rocky Mountains of Missoula, Montana.