Today, we will be taking a deep dive into knowing about Compressor Ratio, how it affects the audio, how to find the sweet spot, and what can be done to enhance the music experience using the right Compressor Ratio.
What is Compressor Ratio?
Compressor Ratio is a fundamental parameter in Audio Compression that will quantify how much compression will be applied to an incoming audio signal.
Compressor Ratio refers to the relationship between the input level of an audio signal and the corresponding output level after compression, as it determines how much the Audio Compressor attenuates or reduces the audio signal level once the signal crosses the preset threshold.
Compressor Ratio is always expressed as a numerical value, such as 2:1, 4:1, or 10:1. A 2:1 ratio means that for every 2 dB above the threshold, the output will be reduced to 1 dB.
How Does Compressor Ratio Affect the Audio
Compressor Ratio gives you control over the degree of compression to be applied to the audio signal above the threshold level. Let's see how higher or lower Compressor Ratios result in different sonic changes in the audio track.
Dynamic Control
Audio Compressor is used to manipulate the dynamic range of the audio signal.
A higher Compressor Ratio, such as 10:1 or above, will allow you to produce more aggressively compressed results, which means the peaks of the audio track will be reduced much more. While Lower Compressor Ratios, such as 2:1 or 4:1, will produce a much gentler compression allowing you to preserve the natural dynamics of the track.
Transparency
Lower Compressor Ratios are used when the Sound Professional is going for a transparent compression, i.e., a subtle, almost imperceptible effect to the listener, retaining the natural dynamics of the sound.
On the other hand, higher ratios will give out a more audible compression effect, where the reduced peaks and increased sustain become noticeable, again used to add a certain character and impact to the audio.
Sustain and Decay
Higher Compressor Ratios tend to enhance the sustain of the incoming audio signal by reducing the audio volume beyond the threshold for a much longer duration in instruments or genres such as rock guitar solos.
Lower ratios will contain the natural decay and allow a more transient to the characteristic, resulting in a more natural and less prolonged sustain.
Levelling and Balance
Higher ratios will effectively reduce the volume of louder elements, such as vocal peaks or instrument transients, bringing them closer to the quieter parts of the audio. This property allows a Sound Professional to create a more consistent and balanced mix.
While lower ratios will have comparatively less level reduction and hence might lead to more natural fluctuations in volume in the track.
Artistic Expression
The choice of Compressor Ratio gives the professional sound control over their personal and unique artistic expression. Higher ratios often achieve a more "in-your-face" or aggressive sound, where the compressed elements will be more prominent in the entire mix, which is most seen in genres like heavy metal or EDM.
Lower ratios provide a subtler compression, usually used to keep things simple and not expressive per se.
How to Set Compressor Ratio
Setting the compressor ratio is one of the most critical steps in achieving your audio track's desired dynamic control and audio characteristics. So, let us guide you on how you do it.
While there is no one-size-fits-all approach to Compressor Ratio, following the steps below will help you reach the sweet spot.
Understand the Audio Material
As an artist, you must be clear about the material you're working with. You will have to give in time to understand the original dynamics of the track or instrument and identify what areas require compression in the first place.
Once familiar with the original track, figure out what output you want. Try to visualize your desired results.
Set the Threshold
Setting the threshold level will be your first step in the process. The threshold is the level at which, once crossed, the compressor will start to compress the incoming audio signal.
Set the threshold to a level where you feel the compressor should start attenuating the audio, and ensure you see that it affects the louder peaks you want to compress. Use your ears and visually monitor the gain reduction meter to find the appropriate threshold level.
Start with a Moderate Ratio
Coming to setting up the Compressor Ratio, from our experience, we suggest that you always begin with a moderate ratio setting. 2:1 to 4:1 is often a good starting point for most audio material.
A softer Compressor Ratio will have a gentle compression, allowing you to retain the natural dynamics of the audio.
Observe and Adjust the Ratio
Pay attention to the produced audio signal once you have activated the compressor with a smaller ratio. Evaluate if you have achieved the desired effect. If not, keep increasing or decreasing the ratio until you get the right sound.
Increase the ratio if you need more compression, and decrease it if you want to retain more of the audio's natural dynamics.
Consider Multiple Compression Methods
If you need more nuanced control over the dynamics, you can also opt for Serial or Parallel Compression, which involves cascading compressors in a chain. Each Compressor has a different ratio and setting.
These methods allow a Sound Professional to manipulate different parts of the same mix to different compression levels, allowing them more control to achieve the desired balance, control, and coloration.
Fine-tune Other Parameters
If you feel you have hit the right spot with Compressor Ratio, start adjusting other parameters to get the final sound you want. Do not forget that the Compressor Ratio is just one parameter among several that shape the compression effect. Once you start with other things, you might have to go back and tweak the Compressor Ratio again.
Compression Ratio Starting Points for Common Instruments
With the years we have spent in the industry, we know, as a rookie, it is extremely hard to find the right spot, to begin with. You will be confused as a Compressor Ratio for one instrument might go completely wrong when used with other instruments.
Hence, it can be helpful for beginners to have some starting points for the Compressor Ratio when applying compression to individual instruments in a mix.
PS- These are just recommendations we have drawn from our experience and are only mentioned so that you can have a foundation for dialing in the right amount of compression for a balanced and cohesive mix. Each instrument, recording, and musical context is unique, and you should use your ears and judgment to fine-tune the compression settings to achieve the desired outcome.
Do not forget that other parameters of Audio Compression will also come into play, and you should consider them too.
Vocals
You should always start with vocals, and you will mostly find good results from gentle and transparent compression so that you do not destroy the natural dynamics and expressiveness.
We feel that starting with a ratio of around 2:1 to 4:1 will allow you the right amount of control to manipulate the vocal peaks and even out the overall level. You can go higher if you want more assertive and upfront vocal sounds in genres like rock or pop.
Remember that the vocalist's dynamic range and style of music will play a huge role in this. and the desired amount of compression. Higher ratios can be used for
Drums
Drums are an instrument that adds energy to the track and hence usually require a more aggressive approach to control transient peaks and provide a consistent and punchy sound.
Kick Drum: For a Kick Drum, we feel a ratio between 4:1 and 8:1 is perfect as it allows you to emphasize the sustain and body of the kick drum and simultaneously control excessive low-frequency peaks.
Snare Drum: Based on our firsthand experience, we can vouch that starting with a ratio of 4:1 to 6:1 is great with a snare drum as it helps control the snare hits and provide a more controlled and present sound.
Toms: A ratio of around 4:1 to 6:1 will benefit the sound of the Toms if you want to enhance sustain and ensure a more even level across different tom hits.
Bass
Compressing the Bass instruments is critical if you want to provide a balanced and consistent low-end foundation without killing the natural dynamics of the instrument.
We recommend that you always start with a ratio of around 3:1 to 6:1 to control the excessive peaks and ensure a more even bass level. But keep in mind that the Compressor Ratio for bass will have to be adjusted based on the style of music, the bass player's playing technique, and the amount of compression you are looking for.
Guitars
A moderate Compressor Ratio of around 3:1 is good for Electric and acoustic guitars to maintain and even out the dynamic performance while adding sustain. This ratio will help you to control the peaks while retaining the instrument's natural dynamics.
Keyboards and Piano
Keyboards and Pianos are the kind of instruments that usually require zero to minimal compression because their natural dynamics contribute to the expressive nature of the instrument.
We suggest that you should go with a gentle ratio of around 2:1 to 4:1 to control peaks while maintaining the consistent sound of the keyboard or the piano. You must also adjust the ratio based on the playing style, the dynamic range of the particular keyboard or piano, and the genre you are working on.
Conclusion
In conclusion, we can say that understanding the compressor ratio is crucial for achieving the desired audio compression results, affecting the dynamic control, transparency, sustainment, leveling, and artistic expression of the audio.
By setting the compressor ratio appropriately, sound professionals can shape the audio's character, balance, and impact. One should not forget that it is important to consider the specific characteristics of each instrument and musical context when determining the starting points for compressor ratios.
Ultimately, by carefully considering the Compressor Ratio and other parameters, sound professionals can harness the power of audio compression to enhance the quality and impact of their audio productions. Keep in mind that Experimenting, learning, and evolving is the key!
