macOS only plays through one speaker at a time because its Sound settings are built around a single default output, by design, on every Mac. This is normal behaviour, not a limitation or a fault. Apple does include a way to deliberately combine outputs, Audio MIDI Setup's Multi-Output Device, but it is opt-in rather than automatic.
It is a reasonable question. Plenty of Macs sit near two, three, even four things capable of making sound: built-in speakers, a monitor with its own speakers, a pair of AirPods in range, a USB interface on the desk. It would seem simpler if a Mac just used all of them. Instead, System Settings hands you a single list and a single tick mark. Here is why that is the deliberate design, not an oversight, and what your actual options are.
Why does macOS only ever pick one output?
Open System Settings, then Sound, then Output, and you get a plain list of every device macOS currently knows about, with exactly one ticked. That tick is the default output, and it is the only thing that will make a sound. There is no checkbox to tick two devices, no "also play here" option, nothing. The entire audio system is built around routing everything, system alerts, music, calls, video, to whichever single device holds that tick.
This is consistent across every Mac and every version of macOS. It is not something that varies by model, by chip, or by how many speakers you own. The Sound pane has always modelled output as a single choice, because a single choice is what nearly every situation actually calls for.
Why is a single default output the right choice for most people?
Think about what the alternative would actually feel like. If a Mac played through every connected device automatically, plugging in a USB microphone with a built-in monitor speaker, walking near a paired Bluetooth speaker, or leaving an old pair of headphones connected in a drawer could all start making noise the moment something played. You would spend more time hunting down which device would not stop talking than you would save by not clicking a menu.
A single, clearly chosen output avoids that entirely. Most people, most of the time, want their sound coming from one clear place: their headphones while working, their desk speakers at home, the conference room's speaker during a call. macOS defaulting to one device, and making you choose deliberately when you want more, is a sensible default for the situation almost everyone is actually in. It is not that Apple could not build automatic multi-device playback. It is that automatic multi-device playback would be wrong far more often than it would be helpful.
How do you get sound out of more than one speaker on purpose?
Apple's own answer is a feature called a Multi-Output Device, built into an app called Audio MIDI Setup that ships with every Mac. Open it, click the plus button in the bottom-left corner, choose Create Multi-Output Device, and tick every real output you want included, your desk speakers and a Bluetooth speaker, say, or two sets of headphones for two people watching the same video. macOS then treats that combination as one selectable output in the Sound menu, same as any single device.
The important part is that nothing about this happens on its own. You have to open Audio MIDI Setup, you have to tick the devices yourself, and the combination only exists because you built it. macOS will never quietly decide to play through several speakers at once; the single default stays the default until you deliberately construct something different.
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Download for MacWhat is the trade-off of turning that feature on?
A Multi-Output Device is not a real speaker, it is a wrapper macOS builds to send one stream to several real outputs at once. None of the outputs inside it shares a single volume with the group, so the volume slider in the menu bar, and your keyboard's volume keys, grey out and stop working the moment you select it. This happens on every Multi-Output Device, on every Mac, every time, for the same structural reason: there is no single volume value for macOS to control. Our guide to why the volume slider greys out on a multi-output device covers the two free workarounds, and why both fall short.
Chorus builds groups the same way Audio MIDI Setup does, using the same built-in mechanism, but changes every real device's own volume together when you move one slider, so the group keeps a working slider and your keyboard's volume keys instead of losing them. It also holds each device's balance, so a speaker you have set quieter because it sits closer to your desk stays at that level every time you turn the group on.
For the step-by-step on building a Multi-Output Device, see Apple's own guide to Audio MIDI Setup.
Frequently asked questions
Why can my Mac only play through one speaker at a time?
Because macOS's Sound settings are built around a single default output by design, not as a limitation. System Settings, then Sound, then Output, is a list where you pick exactly one device, and everything on the Mac plays through whichever one is ticked. Every Mac ships this way.
Why doesn't macOS just play sound out of every connected speaker automatically?
Because most people, most of the time, want sound coming from one clear place rather than scattered across whatever happens to be plugged in or paired nearby. A single default avoids a Bluetooth speaker in another room, a monitor's built-in speakers, and your headphones all making noise at once by accident.
Is there a built-in way to play through several speakers at once on a Mac?
Yes. Audio MIDI Setup, an app Apple includes with every Mac, has a Multi-Output Device feature. You tick two or more real outputs and it combines them into one selectable device, so anything you play goes to all of them together. It only combines outputs you deliberately choose, nothing happens automatically.
What is the downside of combining outputs with a Multi-Output Device?
The volume slider and your keyboard's volume keys stop working, because a Multi-Output Device has no volume of its own to control. You have to open Audio MIDI Setup and adjust each real device separately. Our guide to the greyed-out volume slider covers why this happens and how to get one working slider back.
Does Chorus let me play through more than one speaker at once?
Yes. Chorus groups outputs using the same built-in mechanism as Audio MIDI Setup, but gives the group a single real volume with per-device balance, so you get one working slider instead of a greyed-out one, plus a keyboard shortcut to turn the group on or off.
