Compressor Question

[BigEZ]

Hi All,

When someone refers to "3db" on a compressor, are they referring to Gain or Gain Reduction? I have a knob for both on my RNC and not sure if I should set one or both. Please help.

Thanks,

 

[bouldersoundguy]

Most likely they are referring to gain reduction. There isn't a control for gain reduction, it is a consequence of the threshold, ratio and attack settings interacting with the level of the signal.

 

[BigEZ]

Hey boulder,

That's what I meant, my apologies. So when they refer to "3db" I should set it to the +3db and then set the gain to -3db?...OR...Should the threshold be set to
-3db with the gain set to +3db?

Thanks,

 

[Bristol Posse]

Hey boulder,

That's what I meant, my apologies. So when they refer to "3db" I should set it to the +3db and then set the gain to -3db?...OR...Should the threshold be set to
-3db with the gain set to +3db?

Thanks,

That's really an impossible question to answer without the context of an audio signal

Setting the threshold to -3dBU ratio 8:1 will do radically different things depending on your input signal. If your input signal is peaking at -4dBU then a threshold of -3dBU would theoretically pass the signal uncompressed and adding 3dB of make up gain would just make the whole track louder with no compression. I say theoretically because on your RNC if you are in Really Nice mode the compressor knee is very soft and the compression starts kicking in way below the threshold

If you have another signal coming into the compressor peaking at +8dBU with the same settings as above (threshold at -3dBU and the ratio at 8:1) youd get approximately 9.5 dB of gain reduction on the peaks. depending on the type of material with the 3dB of makeup gain this could seem a great deal quieter, a little louder or not much different.

To make a long story short you simply have to set a compressor so that it gives you then end result you are after and sounds good. The actual numbers don't really mean much outside of good gain staging (Which is why plugin compressor presets are so laughably meaningless)

YMMV

 

[miroslav]

To make a long story short you simply have to set a compressor so that it gives you then end result you are after and sounds good. The actual numbers don't really mean much outside of good gain staging (Which is why plugin compressor presets are so laughably meaningless)

Right...this is what I was getting at in the OP's other "compressor" thread. Giving numbers for a comp is meaningless without considering the specific signal going in...and what you want coming out of the comp.

If you want to drive the comp harder with a hotter input signal...-3dB for the Threshold might be just right to give you the amount of compression you are after. If the signal is lower going into the comp...-3dB on the Threshold might not even move the needle/meter....
...and then there's the choice of Ratio in conjunction with the input signal level, Threshold, Attack and Release and make-up gain.

Listen...bypass, A/B and listen. That's the best way to find the right comp settings.

 

[bouldersoundguy]

Hey boulder,

That's what I meant, my apologies. So when they refer to "3db" I should set it to the +3db and then set the gain to -3db?...OR...Should the threshold be set to
-3db with the gain set to +3db?

Thanks,

There is any number of settings that could end up causing 3dB of gain reduction, and it totally depends on the signal being processed. Settings that got someone else 3dB of reduction on their signal might get you no reduction or 10dB. More importantly, their settings may sound bad on your signal.

What you really should be thinking about is how your track sounds dynamically in the context of the mix and what you would change. Then try various settings until your track's dynamics fits better with the other things in the mix.

 

[aaronmcoleman]

If you have an rnc, follow the instructions in other posts, and learn to use the compressor. Experiment. The gain on the rnc is make up gain. Since compression lowers the volume overall, make up gain can get the overall volume back up to where it was.

 

[BigEZ]

Most likely they are referring to gain reduction. There isn't a control for gain reduction, it is a consequence of the threshold, ratio and attack settings interacting with the level of the signal.

So when I see a post where someone suggests using 3-5db of Gain they are referring to Threshold...I understand that thus far. But the RNC threshold Knob has settings from -40 to 20, so when 3-5 db is suggested is it negative 3-5 or positive 3-5?

Thanks,

 

[bouldersoundguy]

So when I see a post where someone suggests using 3-5db of Gain they are referring to Threshold...I understand that thus far. But the RNC threshold Knob has settings from -40 to 20, so when 3-5 db is suggested is it negative 3-5 or positive 3-5?

Thanks,

No, they are talking about gain reduction, as in a lowering of the signal level when it goes above the threshold. Any number of settings could result in 3dB (or whatever) gain reduction. You don't "use" gain reduction, you get gain reduction as a result of lowering the threshold and raising the ratio. It's simply a reference point indicating very approximately what the compressor is doing.

Setting the threshold divides the signal into Above and Below. That which is Below the threshold is not affected by the compression, no gain reduction. That which is Above is affected to some degree controlled by the ratio. The higher the ratio and/or the lower the threshold the more the gain will be reduced.

 

[BigEZ]

This is very confusing to me but I do appreciate you all taking the time to explain.

 

[miroslav]

Your RNC Threshold with its -40 to +20 allows you to find the point (aka "the threshold") where the incoming audio signal is going to activate compression. This is why we are telling you that compression settings mean nothing without considering the level/type of incoming signal and what you want at the output for your song/mix.

Your incoming signal will be at some level...let's say it is +8 (pretty hot). So, to get the compressor to work, your RNC Threshold setting will need to be set somewhere from +8 on down to -40. If you set it above +8, the threshold will never be crossed by the incoming signal, therefore the compressor will simply let that signal pass untouched.
Now...to get -3 dB gain reduction, that will depend on how far down from +8 you set the Threshold crossover point and the Ratio you choose. The further down you set the Threshold and the greater the Ratio, the more gain reduction happens. Look at the meters showing gain reduction and find the combination that yields -3 dB gain reduction and that works for you. It's not an either/or thing...it will sound different if you lower the Treshold further but leave the Ration alone...VS...if you leabe the Thresahold alone but increase the Ratio.
It's up TO YOU beased on YOUR desired sound.

So...reading that someone is applying a -3 dB amount of gain reduction on "vocals" or "guitar" or "bass" or anything...
...really means NOTHING TO YOU, unless they are using exactly the same gear, and recoding exactly the same tracks for exactly the same song to be mixed exactly like yours.

Get it?