How can I make my Macbook Pro's headphone jack stop "humming"?

Solution 1:

I found the solution to my problem. For some reason (who knows why) the headphone output was set to 16-bit. Of course that's going to sound awful.

To fix this, head to 'Audio MIDI Setup' (can be found with Spotlight) and change the 'Built-in Output' to 32-bits.

Solution 2:

My macbook air also hums into my Bose earbuds. Disconnecting the magsafe power cable lessens it, but not by much. Touching the body of the computer dramatically decreases the hum (the more skin that touches, the greater the decrease).

Solution 3:

What you are hearing is the intrinsic noise of the Macbook's DAC and output buffers.

The output does actually power down when it goes unused for a certain period of time, which is why the noise goes away. The analog output is powered down to save battery.

Unfortunately, since the noise is intrinsic to the system, the only way to disable it is to completely disable the ability to output any sound.

There may be a way to modify the period of time it takes before the output gets powered down, but I am not familiar with any.

Solution 4:

Closing my web browser solved my buzz problem!

My Mac Pro started an electronic type of buzzing sound suddenly in the past few weeks.

The sound was coming from the audio output (headphone jack or firewire audio output - same issue)

I had incorporated some new speakers recently and I thought maybe it was some kind of new grounding problem. While attempting to pursue a solution to the problem, on a whim I decided to shut down my mac to see if that might do anything.

While preparing to shut down I was closing various programs. Then I closed down Google Chrome, on which I had about 10-15 tabs open... and the sound went away!

I've never experienced something like this before. I'm imagining perhaps it was some kind of issue with one of the pages I had up.

I've often had multiple browsers windows, each with multiple tabs open and never had this kind of thing happen... so this was unique experience for me.

Solution 5:

The hum is also present for me, even with unplugging everything. Actually, if you have a look (or at least, for me, this is the case) if you touch the body of the machine, it ceases to hum. It must be some kind of static buildup of charge on the aluminium body, and when you touch it, your body acts as a very large condenser.

When you can ground the machine with your body, you might want to check the power cord and replace an ungrounded "duck head" or cord with one that goes to a properly grounded wall receptacle. Also, take a toothbrush to the magsafe connectors to ensure all the springs work and make contact to the connector on the mac.

If you use an external USB I/O (I use a mixer, for I'm a session musician), the hum is not plagueing the alternative sound source.