USB DAC Volume Greyed Out on Mac? Get a Working Slider

Short answer: many USB DACs tell macOS they have no volume control the Mac can adjust, so the slider is greyed out or does nothing and you are meant to use the DAC's own knob. If that isn't practical, SoundDial gives such devices a software volume slider, plus a sample-rate menu and per-app levels.

You plug in a USB DAC, start some music, press the volume keys, and nothing happens. The slider in the menu bar is greyed out, or it moves but the level stays the same. It looks like a bug. Usually it isn't.

Why the volume is greyed out for some USB DACs

When you connect a USB audio device, macOS asks it what it can do. Some devices report a volume control that the Mac may set; macOS then connects it to your volume keys and the Sound menu. Other devices report no such control, and macOS has nothing to adjust, so the slider is unavailable.

Many good DACs and headphone amps do this on purpose. The idea is that the Mac sends a full-level digital signal and you set the loudness with the analog volume knob on the unit, after the conversion. If your DAC has a knob and the Mac slider is greyed out, that is very likely what the maker intended.

When it becomes a problem

The "use the knob" answer stops working in real setups:

• The DAC has no knob. Small USB dongles and some interfaces have no volume control of their own and don't offer one to the Mac either. You're stuck with whatever level your amp or powered speakers are set to.
• The knob is out of reach. A DAC behind your monitor or under the desk turns every volume change into a trip.
• You need different levels per app. Even a perfect hardware knob is one control for everything. It can't make a call quieter than your music.

macOS has no switch in System Settings that adds a volume control to a device that doesn't report one.

What to try first

These cost nothing:

• Use the hardware knob, or the volume on your amp or powered speakers. If you have one within reach, it's the cleanest option.
• Check the DAC's own app or settings. Some devices come with a control panel or a setting that lets the computer set the volume. If yours has one, turning it on can make the Mac slider work.
• Look in Audio MIDI Setup. Open Audio MIDI Setup (Applications > Utilities) and select the DAC. If a volume slider appears for it, you can set the level there. If there's no slider or it's greyed out, the device only takes a fixed level.

If none of that helps, you need a volume control on the Mac side.

A software volume slider for your DAC

SoundDial is a menu-bar volume mixer for Mac. In version 2.0 its output card shows the current output device, a format label (for example "48 kHz · 32-bit") and the output volume. When the device has no hardware volume, SoundDial shows a volume slider instead, with the note "This device has no volume control of its own, so SoundDial sets the level for every app."

That is exactly what it does: SoundDial applies software gain to every app it controls, and it remembers that level per device. Plug the DAC back in tomorrow and it comes back at the level you left it.

If you prefer the keyboard or a launcher, SoundDial also has an output-volume URL command (sounddial://output-volume?value=…) that works from any launcher or script that can open a URL, or with open in Terminal.

Change the sample rate without Audio MIDI Setup

If your DAC offers more than one sample rate, the output card also has a sample-rate menu, with rates from 44.1 to 384 kHz depending on what the device supports. You don't have to open Audio MIDI Setup to switch between, say, 44.1 kHz for music and 48 kHz for video. There's a sample-rate URL command for this too. If the device offers only one rate, the menu isn't shown.

Send just one app to the DAC

You don't have to make the DAC your system output. With Play Through you can send a single app there:

1. Click the ⋯ button on the app's row, for example Spotify or Music.
2. Choose Play Through and pick your DAC.

That app plays on the DAC while calls, the browser and notifications stay on your speakers or headphones. Several apps can use different devices at the same time. Choose Same as the app (default) to undo it. If the DAC is unplugged, the app falls back to its own device, then to the system default.

Per-app levels on top

Whatever your DAC does, SoundDial gives each app that plays sound its own slider from 0 to 200%, a mute, and in 2.0 its own equalizer and left/right balance:

• Lower the browser, raise the music player, mute what you don't want to hear.
• Switch the system output between the DAC, speakers and headphones from the output card's device menu.
• Save the mix with Save current mix as a profile. A profile stores each app's volume, mute, EQ and balance; it doesn't store which device an app plays through.
• During calls, Lower other apps during calls (on by default) plays other apps at 30% of their volume and brings them back when the call ends. You can change the level from 5% to 80% or turn it off.

With Settings > General > When an app opens set to Remember last, SoundDial brings back each app's volume, mute, balance, EQ, output device and pinned state when the app opens.

The honest tradeoff

Software volume lowers the digital level before the DAC converts it, while an analog knob lowers it afterwards. If you have a good analog knob within reach and only need one level for everything, use the knob. If you have no usable hardware control, or you need per-app levels that macOS doesn't offer, a software slider is the practical choice, and it beats a slider that does nothing.

A few limits: SoundDial works per app, not per browser tab, and it is stereo only. It is sandboxed, needs no account, has no network entitlement and does not install a virtual audio driver.

SoundDial, a per-app volume mixer for Mac needs macOS 14.2 or later and costs €14.99 one-time purchase on the Mac App Store, no subscription.

Get SoundDial on the Mac App Store.