Yes, a Mac can play to two Bluetooth speakers at once, and the tool for it is already on your machine. Audio MIDI Setup glues both speakers into one, and macOS then treats that as a single place to send the sound. Ten minutes of clicking and you have music in two rooms.
It won’t give you your volume keys back, though. The two speakers also slide apart as they play, until what you hear is an echo, and on some Macs the second speaker knocks the first one off before you get that far.
How to connect two Bluetooth speakers with Audio MIDI Setup
macOS sends sound to one speaker at a time. Audio MIDI Setup gets around that by building a new one out of several real ones.
1. Pair and connect both speakers. Open System Settings, click Bluetooth, and pair each speaker in turn. Then check that both say Connected, not just paired. If the first one drops off the moment the second joins, skip to the last section before you go any further.
2. Open Audio MIDI Setup. It sits in the Utilities folder inside Applications, and Apple’s guide to playing audio through multiple devices at once covers the same steps. Faster: press Command and Space, type Audio MIDI Setup, press Return.
3. Create the combined device. Click the plus button in the bottom-left corner of the window and choose Create Multi-Output Device. A new entry appears in the left-hand list. Double-click its name to call it something you’ll recognise later.
4. Tick the speakers. With the new device selected, the right-hand pane lists everything your Mac can play to. Tick the Use box beside each Bluetooth speaker. Leave your Mac’s own speakers unticked unless you want them in on it too.
5. Choose it in the menu bar. Click the sound icon in the menu bar, or open Control Center and click Sound, and pick Multi-Output Device. It also shows up under System Settings, then Sound, then Output. Press play in any app and both speakers should sound.
That’s the whole built-in route. It costs nothing and it works from any app, which is more than most people expect from a utility hiding in the Utilities folder.
Why the volume keys stop working
While a Multi-Output Device is selected, the volume keys on your keyboard do nothing, and the slider in Control Center goes grey. macOS has no way to set the volume of a device it assembled out of other devices, so it hands the job back to you.
In practice that means walking over to a speaker and pressing its buttons, or reaching for the volume slider inside whatever app is playing. Fine for a podcast in the background. Less fine when someone rings the doorbell.
Why two Bluetooth speakers sound like an echo
Every Bluetooth speaker keeps a little music in reserve before it plays, so a rough moment on the radio link doesn’t turn into a gap in the song. How much it keeps is the speaker’s own business. Two speakers from different makers, or two models from the same maker, rarely agree.
A Multi-Output Device sends the same sound to both at the same instant and leaves the rest to them, so one plays behind the other. In two rooms with a wall between you may never notice. Standing where you can hear both, a gap as short as a twentieth of a second is plenty to sound wrong.
Audio MIDI Setup does have a Drift Correction tick box, which is for wired studio gear whose clocks run at slightly different speeds. It does nothing about a Bluetooth speaker’s head start. What you want is to hold the early speaker back until it lands with the late one, and macOS has no control for that.
Audiout is where we put one, since it mixes the sound before it leaves your Mac rather than asking macOS to. Each speaker gets its own volume slider, and one Main Audio sits over all of them, so the keyboard keys go back to doing what they say on the key. It’s €24.99 once, and the free 14-day trial of Audiout for Mac has every feature in it.
Measuring the gap is the part that needs a microphone. Audiout Remote, the free iPhone app included with Audiout for Mac, is coming soon and will do it with the phone in your hand. How measuring with your iPhone will work previews the steps.
Today, the “Align by ear…” menu item runs a wizard that measures with your Mac’s microphone, or plays a click from two speakers and asks which one you heard first, about fifteen rounds of it, and keeps the answer. Aligning a Bluetooth speaker by ear walks through a round. One thing to expect either way: a Bluetooth speaker doesn’t come back with exactly the same head start every time it reconnects, so a speaker that has wandered wants measuring again.
Why only one Bluetooth speaker will connect
On some Macs, connecting a second Bluetooth speaker knocks the first one off. Whether it happens comes down to the Mac, the version of macOS and the speakers themselves, and there’s no setting that changes it. No app changes it either, because the limit sits underneath all of them.
So check the Bluetooth list before you build anything. If both speakers sit there saying Connected at the same time, you’re clear. If the first one drops every time the second joins, the built-in route is closed on that Mac, and no amount of clicking in Audio MIDI Setup will open it.
The way out is to make one of the two rooms a Wi-Fi room. AirPlay speakers reach your Mac over the network instead of the Bluetooth radio, so they aren’t competing for the same slot, and a Mac can drive several of them at once. Apple’s AirPlay support note covers getting one set up. If you already own a HomePod or an AirPlay speaker gathering dust, that’s the one to move.
Which route to take
If your two speakers live in different rooms with a door between them, the built-in Multi-Output Device is genuinely enough. You’ll put up with walking over to change the volume, and you’ll never hear the echo, because you can only hear one speaker at a time anyway.
If they’re both in earshot, the timing is what will bother you within about four minutes, and holding one speaker back is the piece macOS doesn’t have. Either way, start in the same place: open the Bluetooth list and make sure both speakers say Connected at once. Everything else is downstream of that.
Common questions
Can a Mac connect to two Bluetooth speakers at once?
Usually, yes. Pair both speakers in System Settings, check that both say Connected rather than just paired, then open Audio MIDI Setup and combine them with Create Multi-Output Device. Choose that device in the menu bar and both speakers play. Some Macs will only hold one Bluetooth speaker at a time, which you find out at the pairing stage.
How do I fix the echo when two Bluetooth speakers play together?
The echo is one speaker running a fraction of a second behind the other, and the cure is to hold the early one back until they land together. macOS has no control for that, so it takes an app that mixes the sound before it leaves your Mac. Measuring the gap with a microphone is quick. Doing it by ear takes a few minutes.
Why are my volume keys greyed out on a Multi-Output Device?
macOS cannot set the volume of a device it assembled out of other devices, so the keyboard keys and the Control Center slider both go dead while one is selected. Volume then lives on each speaker's own buttons or inside the app that is playing. Switch back to a single speaker and the keys work again.