How to play audio through two speakers at once on a Mac

The short answer: open Audio MIDI Setup, create a Multi-Output Device, tick the speakers you want, and choose it as your sound output. Both speakers then play the same audio at the same moment, with no extra software and nothing to buy. It takes about two minutes.

The longer answer is the reason you are probably reading this at all. A Multi-Output Device has no volume control of its own, so the slider in your menu bar greys out and your volume keys stop responding. Everything still plays. You just lose the one control you use most. Below is how to build the thing properly, the two settings that decide whether your speakers stay in step, and what to do about the volume.

Build the Multi-Output Device

Plug in or connect every speaker first, so they all appear in the list before you start.

1. Open Audio MIDI Setup. It lives in Applications, inside the Utilities folder, or press Command and Space and type the name.
2. Click the + button at the bottom left of the device list and choose Create Multi-Output Device.
3. On the right, tick the Use box next to each output you want to include.
4. The device at the top of the ticked list is the primary one. Its clock sets the pace for the rest, so choose something wired and dependable rather than a Bluetooth speaker.
5. Tick Drift Correction for every device except the primary one.
6. Double-click the new device's name in the sidebar to rename it. Something like Desk Speakers is easier to spot later than Multi-Output Device.
7. Select it as your output, either in System Settings under Sound, or by holding Option and clicking the volume icon in the menu bar.

That is the whole free method. Audio now goes to both speakers, untouched, and any app that uses your normal system output will follow it without being told.

Why does the volume slider stop working?

A Multi-Output Device is not really a device. It is a wrapper that takes one stream of audio and hands the same copy to several real outputs. Those real outputs each keep their own volume, and the wrapper has none, so when you press the volume key macOS has nowhere to send the instruction. The slider greys out and the keys do nothing at all.

The official way round it is tedious. You select each real device on its own in Sound settings, set its level, then switch back to the group. Change your mind about how loud the room should be and you do the whole round trip again. Speakers with a physical dial are easier, right up to the point where one of them is a display with no dial anywhere.

Keeping two speakers in step

Every audio output has its own clock, and no two clocks run at exactly the same rate. Left alone, one device slowly slips ahead of the other. Over a few minutes that turns into a thin, hollow, phased sound if the speakers are close together, or an audible echo if they are at opposite ends of a room. It is the single most common complaint about multi-output setups, and it is entirely fixable.

Drift correction is the fix. One device acts as the clock, and the others are continuously corrected to match it, which is why step 5 above matters more than it looks. Two Studio Displays over Thunderbolt is about the easiest case there is. A pair of separate USB interfaces is the hardest, because each carries its own independent clock.

Bluetooth is a separate problem and worth being blunt about. Wireless outputs add a delay of their own, measured in tens of milliseconds, and drift correction does not remove it. Mixing a wired speaker with a Bluetooth one will sound offset no matter how carefully you set the rest up. Keep a group wired, or make it entirely wireless.

Getting one real volume back

This is the gap Chorus was built for, and yes, it is ours. It is a menu-bar app that groups your outputs and then sets each real device's own volume rather than trying to change a volume the group does not have. One control moves the whole group, your volume keys work again, and the on-screen volume display comes back with them.

Because it is setting real levels, it can also hold them at different points. If one Studio Display sits closer to you than the other, you can pull that side down to 66% and leave the other at 100%, and the balance stays put every time you use the group.

The rest is the same set of jobs, in one place: choose which microphone you are using, send individual apps to different outputs so a call stays on your headphones while music plays at your desk, and bind a keyboard shortcut to any setup so you can change the lot without opening anything.

It installs no driver and no kernel extension. It uses the aggregate and multi-output support macOS already has, which is the same machinery you just used by hand. Drag it to the Trash and your Mac is exactly as it was. Chorus is $4.99 once after a 30-day free trial that asks for no account and no card details, covers up to three Macs on one licence, and runs on macOS 13 or later on both Intel and Apple Silicon.

Which of the three should you use?

SoundSource 6, by Rogue Amoeba, deserves more than a row in a table. At $49 it costs roughly ten times what Chorus does, and it does considerably more than group your outputs: a full equaliser, audio effects, and Audio Unit plugin support on any app or device you like. If you want to shape how something sounds as well as decide where it goes, it is the better tool and nothing here argues otherwise.

So pick by what you actually need. Set it once a year and rarely touch the volume, and Audio MIDI Setup is free and already on your Mac. Want your speakers to play together with a volume key that works, for the price of a coffee, and Chorus is the smaller answer. Want an equaliser and effects on top, and SoundSource is worth its $49. Prices checked August 2026.

If something is not working

• Only one speaker plays. Go back into Audio MIDI Setup and check the Use box is ticked for both, and that the Multi-Output Device itself is the selected output rather than one of the devices inside it.
• The volume keys do nothing. That is the expected behaviour described above, not a fault. Set each device's level individually, or use something that sets them together.
• There is a faint echo or the sound is hollow. Drift correction is off on one of the devices, or one of them is wireless.
• One app ignores the group. Some audio applications choose their own output device in their own settings and never look at the system one. Check inside the app.
• The group breaks when a device unplugs. A Multi-Output Device quietly drops a device that disappears and does not always add it back. Reopen Audio MIDI Setup and re-tick it.

Frequently asked questions