Difference between ratios in compression?


New member
Hi guys,

Can someone possibly explain the differences between setting the ratios as 3:1, 4:1 and 10:1. What difference would I expect with each of those ratios?

I use my microphone (RE20) for voiceover, no instruments or singing.

Which ratio is generally seen as the best for voiceover out of those three? Why do some people prefer 3:1 and some prefer 10:1? Why would someone choose one over the other? Is there a certain ratio which is recommended?

The ratio specifies how much compression is applied. At 10:1, the input must exceed the threshold by 10 dB for it to go 1 dB over the threshold at the output.
Lots of people cannot hear compression, until the magic lightbulb moment, then you kick yourself for not realising it before. The trouble is the result is a formula. I dont use it on voice unless I have to, and if you have a breathy singer who makes a lot of noise on the in breath, that’s a great way to hear compression. The only thing I routinely compress is my bass, and it’s always two parameters, the slope so the way that big changes in playing volume get squashed into less. For my bass it will be 3:1 or there abouts because it cures a playing fault I have. When I’m a little unsure of the next note, i play it quieter. A bad habit I got into years ago. 3:1 seems to make these quiet notes sound more normal. usually the other parameter is threshold, as in when the compression starts, based on loudness. Singers can be quiet, or loud, and some work the mic and some don’t even notice there is a mic, so I personally do not have a set compression ratio and threshold. It’s what is needed for that voice, with that mic, and that song.
They pick a value based on the voice, the mic and the working distance. There is no rule to follow. You pick the sound that works best for you. It will be different if you swap mic, person or distance. We’ve said this already. Recording is about your ears, not a rule book.
While there are no one size fits all solutions here, there are some generally accepted best practices. It's also important to understand when you're introducing compression in your chain. If you're compressing after tracking: #1 Use volume automation to manually level the vocal before introducing compression. This will make the job easier for your compressor. If you're compressing on the way in, do your best to maintain a fixed distance from the mic. Try a faster release time to bring up quieter parts of the vocal. When considering what ratio to use, your ears should be making the final call. Make sure you understand the relationship between threshold and ratio. Using higher ratios will generally mean you will back off of the threshold. When you set a compressor to a 10:1 ratio, it basically becomes a limiter, and it completely cuts off any signal above the threshold. For most podcasting / voiceover applications it's common to use a ratio of 2:1 - 6:1. You can leave the vocal much more dynamic than you would if you were trying to mix it with other elements occupying the same frequency range in an instrumental. Try turning the threshold all the way down while adjusting the ratio with a medium attack and a fast release. This will make it easier to hear the differences. Once you like what you're hearing, adjust the threshold to taste.
So, (for voiceover), why would someone go with 3:1 or 10:1? Which would be considered better or common, say?
It doesn't work that way - one has to listen to the track and make a calculation based on what's needed and what one wants to do with the track.