I got a MacBook Pro 13'' early 2013 with OS X 10.10.5 installed and SONY MDR-1A headphones with a headset cable.

When using "headphone" cable everything works as expected. When I use "headset" plugin (the one with 4 grooves on a jack and a mic on a cord) the volume slightly reduces after 1 or 2 seconds.

Can someone explain this behaviour and tell me if it can be fixed?!

2 Answers 2


Headphones volume level is separate from the built-in speaker output. For example you can set the speakers' volume to 0 before plugging in headphones and then adjusting the headphones' volume to something different. When the headphones cable is unplugged, the system goes back to the previous volume value.

If I remember correctly, recent Macs also have a impedance sensor in the headphone jack, so that you can have different volume levels for different headphones based on impedance.

  • It would make sense if I have different types of earphones. But this is the same earphones, the same size cable, just with micro and without it.
    – aim
    Aug 21, 2015 at 15:21
  • I'm guessing it it recognized as a different set of headphones, so it has a different volume level with different jacks.
    – Brethil
    Aug 21, 2015 at 16:51
  • the volume bar, indicating the volume level is not changing. Just the volume itself. And I repeat - when I plug the cord with the mic for the first 0.5 - 1 seconds the level is the same like if I put the cord without mic. Then it reduces slightly.
    – aim
    Aug 21, 2015 at 22:46
  • It takes a while for your Macbook to detect the headphones. As soon as it detects them (1-2 seconds), the volume is changed,
    – Brethil
    Aug 24, 2015 at 19:30
  • The question was why this happens only when the "headset" cord used. the same typo "headphone"cord does not lead to such os behavior.
    – aim
    Aug 24, 2015 at 21:24

OS X remembers volume settings for each headphone. It sets the volume to the last headphone volume level when a headphone is plugged in.

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