Input gain controls how much a microphone's raw signal gets amplified before it becomes a digital recording, essentially how sensitive the mic is to quiet sound. Volume controls how loud something plays back through a speaker or headphones. One shapes what goes in, the other shapes what comes out, and macOS's own wording is the main reason people mix them up.
It is an easy mistake to make. Both show up as a horizontal slider somewhere in Sound settings. Both go from low to high. Both feel, at a glance, like the same kind of control. They are not, and treating a microphone's gain as if it were a volume knob is why so many Mac recordings end up either too quiet to make out or crackling on every loud word.
What input gain is actually doing
A microphone's capsule turns sound waves into a tiny electrical signal, weak enough that it needs amplifying before anything digital can use it. Gain is that amplification. Turn it up and the same whisper produces a stronger signal. Turn it down and only louder sounds register at all. It is set once per microphone, before the signal ever becomes audio a computer can process, which is why some people call it "mic sensitivity" or "input level" instead, and all three names describe the same control.
Get gain wrong in either direction and there is no fixing it afterwards. Set it too low and quiet speech sits buried near silence, forcing anyone listening to strain or turn their own volume up, which brings up every bit of background hiss along with the voice. Set it too high and the signal clips, a sharp digital distortion that appears the moment a sound gets loud enough to exceed what the input can represent. Clipping cannot be smoothed out in an app afterwards. Once a peak has clipped, that part of the recording is permanently damaged.
Why volume is a different control entirely
Volume is a property of output devices, not input ones. It sets how much a speaker or a pair of headphones amplifies the signal already sitting on your Mac before it turns into sound in the room. Nothing about volume touches what a microphone picks up. Turning playback volume all the way up does not make your microphone more sensitive, and turning it down does not protect a recording from clipping. The two sit on opposite ends of the audio chain: gain shapes what goes in, volume shapes how loud what is already there comes back out.
The confusion is not really a technical one. It is a naming one, and it starts with Apple's own settings.
Why macOS calls it "Input volume" anyway
Open System Settings, then Sound, then Input, and the slider under your selected microphone is labelled Input volume. That slider behaves exactly like gain, amplifying the microphone's raw signal before it becomes digital audio, but it borrows a word that everyone already associates with playback loudness. Some third-party apps do the same thing, using "volume" loosely for a microphone control that is really adjusting gain. Once the operating system itself uses the wrong word for the right control, it is not surprising the terminology never settled.
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Download for MacSetting gain correctly, by ear and by eye
Open System Settings, then Sound, then Input, and select the microphone you want to check. Below it sits a live level meter that fills left to right as it picks up sound. Speak at whatever volume you would actually use, a normal conversational tone, not a deliberately loud test, and watch where the meter settles.
The target is the upper-middle range during normal speech, with only your loudest moments, a laugh or a raised word, brushing close to the top. If the meter barely moves while you talk normally, gain is too low and the slider needs to come up. If it is regularly hitting the far right and touching red, gain is too high and needs to come down before anything gets recorded. There is no universal number here, because every microphone, every room, and every voice sits at a different natural level, which is why the meter matters more than any fixed setting.
Where Chorus fits, and where it does not
Chorus switches which input device is active, the same choice covered in choosing which microphone your Mac uses, and does it from the menu bar with a click or a keyboard shortcut instead of two levels of System Settings. That is the whole of its job on the input side.
Chorus does not adjust a microphone's gain or sensitivity, and it never touches the Input volume slider on your behalf. That control stays exactly where it has always been, in System Settings under Sound and Input, set once per microphone and left alone until the room, the mic, or your voice changes enough to need revisiting. Chorus picks which input is live. Getting that input's level right is still a job for the meter above.
For the full detail on Voice Isolation and Wide Spectrum, see Apple's own guide to Mic Modes.
Frequently asked questions
What is the difference between input gain and volume on a Mac?
Volume controls how loud something plays back through your speakers or headphones, which is an output setting. Input gain controls how much a microphone's signal is amplified before it becomes a digital recording, which is an input setting. They apply to opposite ends of the audio chain and adjusting one has no effect on the other.
Why does macOS call the microphone gain control "Input volume"?
System Settings, under Sound and then Input, labels the sensitivity slider "Input volume" even though it behaves exactly like gain, amplifying the microphone's raw signal. Apple reused a familiar word from the output side rather than introducing "gain" to people who have never needed it, which is the main reason the two concepts get confused.
What happens if microphone gain is set too high or too low?
Too low, and quiet speech barely registers, forcing whoever hears the recording to strain or turn their own volume up, which also raises any background hiss. Too high, and the signal clips, producing a harsh, crackling distortion on anything loud, from a laugh to a raised voice, that cannot be fixed after the fact.
How do I set the correct input gain for my microphone on a Mac?
Open System Settings, then Sound, then Input, select the microphone, and speak at your normal volume while watching the level meter. Adjust the slider until the meter peaks comfortably in the upper-middle range during normal speech, with only the loudest moments brushing close to the top and never sitting in the red.
Does Chorus adjust microphone input gain?
No. Chorus switches which input device is active and does not touch a device's own gain or sensitivity level. Gain stays a macOS setting, adjusted in System Settings under Sound and Input, the same place it always has been.
