Hello I've noticed that volume control acts differently on the internal speakers vs internal speakers.

Primarily the fact that the built in audio uses some sort of multiband compression or volume dependent - dynamic equalization and other DSP modifications (I'm guessing a slight reverb as well)? The volume control seems to control dynamics at the lower levels and keeps the frequency response relatively balanced for all volume levels for human speech (preventing overall muddiness or overwhelming sibilance) at the expense of dynamics,

Whereas the external output sends the pure signal and the volume control modifies the gain. A lot of youtube and video content is either poorly mastered and consequently suffer from a lot of boominess, and sudden loud noises, and sibilance. Which are pretty bad when using headphones or nice external speakers.

Consequently I was wondering if there were a way to keep the CoreAudio running? Either by spoofing the internal speakers through the headphone jack or software solutions. Thank you

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    Rogue Amoeba has an app called Loopback that does virtual routing of sound inputs and outputs in software. There are others like it, but you may want to have a look at it and see if it does what you want. Commented Nov 19, 2021 at 22:45
  • You don't want loopback for this. The same company makes SoundSource, cheaper, more consumer-oriented & with AU plugin support.
    – Tetsujin
    Commented Nov 20, 2021 at 8:01

1 Answer 1


I can't say I've ever noticed there being any type of compression on a Mac outputs, unless put there intentionally, or unless you've got Spacial Sound on [which I've never used, because I like to be in charge of my own sound.

I'd suggest SoundSource which can do all you mentioned - it can also use Apple or 3rd party AU plugins.
I use it on all the consumer Macs here to tame cheap speakers [which includes the new iMac, very disappointing straight out of the box] & also on the HTPC 5.1 to bring movie soundtracks under control.

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