Want the same track playing through your MacBook speakers, a Bluetooth speaker, and a pair of desk monitors all at once? macOS can do it - and with the right setup you can even balance the volume of each speaker independently. Here's how.
The built-in way: a Multi-Output Device
macOS has a hidden tool called Audio MIDI Setup that lets you group several outputs into one virtual device. Once it's created, you select it like any normal speaker and your audio fans out to everything in the group.
- Open Audio MIDI Setup (press Command + Space, type its name, hit Return). It lives in Applications → Utilities.
- Click the + button at the bottom-left and choose Create Multi-Output Device.
- In the right-hand panel, tick every output you want to use together - for example your MacBook Pro Speakers and an external USB or Bluetooth speaker.
- For the most reliable sync, set the device with the steadiest clock (usually your built-in output) as the Primary, and enable Drift Correction on the others.
- Now click the volume icon in your menu bar (or open System Settings → Sound) and pick your new Multi-Output Device as the output.
That's the whole trick. Every app - Spotify, Safari, QuickTime - will now send sound to all the speakers in the group at once.
The catch: no master volume, no easy balance
There's a real limitation worth knowing before you commit. When a Multi-Output Device is active, the volume keys on your keyboard stop working and the menu-bar slider greys out. macOS treats the group as a fixed bundle, so you have to change the level of each speaker separately back inside Audio MIDI Setup.
That makes balancing awkward. If your Bluetooth speaker is naturally louder than your laptop, one side drowns out the other and there's no quick way to even them up on the fly. It also can't push any output past the usual macOS ceiling - so if a speaker is quiet to begin with, the group is quiet too. (If that's the bigger issue for you, see how to make your Mac louder than maximum volume.)
A simpler route: multi-speaker with per-device volume built in
If you want multi-output without losing your volume keys or fiddling in a utilities app, that's exactly what Vlume is built for. It includes multi-speaker support with per-device volume, so you can send audio to several outputs at once and set each one's level independently - turn the loud Bluetooth speaker down a touch, nudge the quiet laptop up - all from the menu bar.
Because Vlume is built on Apple's modern Core Audio process-tap API, there's no kernel extension or audio driver to install, no admin password, and no restart. It also boosts system audio up to 800% (8×) past the macOS maximum, with an always-on limiter that keeps the louder, boosted sound clean instead of clipping - handy when one speaker in your group needs more headroom than the others. A built-in 6-band equaliser lets you shape the tone too; here's how to equalise system audio on a Mac if you want to dial it in.
Which approach should you pick?
- Just need every speaker playing the same thing, occasionally? The free Multi-Output Device in Audio MIDI Setup is perfectly fine.
- Want to keep your volume keys, balance each speaker easily, and boost quiet outputs? A dedicated tool like Vlume removes the friction. It's a one-time £39 Pro (1-2 Macs) or £59 Family (up to 5 Macs) - no subscription.
It's also worth a quick note on alternatives: apps like Boom 3D offer rich surround and a large equaliser, while the free, open-source eqMac can boost beyond 100% - though it installs a kernel-level audio driver (which needs your admin password) and has no limiter, so heavy boosting can distort. If you're weighing them up, our Boom 3D vs eqMac vs Vlume comparison breaks down the trade-offs fairly.
One last tip: many Bluetooth speakers run quiet, so multi-output setups often expose just how low macOS keeps the volume - see how to make AirPods louder on a Mac for a related fix. Vlume runs on macOS 14.4+ (Apple silicon and Intel) - try it free for 3 days, no card needed, and set up balanced multi-speaker sound in a couple of minutes.