Install VoluBridge.app.
Open the downloaded DMG and move VoluBridge.app to the Applications folder.
Reference
VoluBridge Reference
This page explains the controls shown in VoluBridge.app: the main window, menu bar, general settings, advanced settings, Optimizer, license area, and diagnostics. Use it as a reference when you want to check what a UI item means.
Output
Select VoluBridge as the Mac output, then send it to the real output device from VoluBridge.
Window
Pinning, Always on Top, and Launch at Login keep VoluBridge available during daily use.
Advanced
Advanced items are usually best left at their defaults.
Quick Start
First things to check
The basic path required to play audio through VoluBridge.
Install the driver.
Follow the first-launch prompt to install VoluBridgeRT.driver. This adds the virtual output device to your Mac.
Select VoluBridge as the Mac output.
Choose VoluBridge in macOS Sound settings or from the menu bar output picker.
Select the output from VoluBridge.
Inside VoluBridge.app, choose the HDMI monitor, DisplayPort monitor, USB DAC, or other real device that should play the audio.
Main Window
Reading the main window
The meaning of the controls and indicators you see most often.
Red close button
Closes the VoluBridge window. It does not quit the app.
VoluBridge title
Double-click the title to toggle Minimum Mode when you want a smaller display.
Green / orange status LED
Shows clock status. Locked means stable, Syncing means alignment is in progress, and Idle means waiting.
Pin icon
Pins the window and saves its position. Use it when you want VoluBridge to stay as a persistent meter/control window.
Minimum Mode
Switches to a smaller window. It is useful when you only want to keep an eye on level or status.
+0.00 ms
Shows the added latency introduced by the VoluBridge path. The goal is to keep the feel equivalent to direct hardware output.
Wave / spectrum display
Shows the rough movement of the current audio, making it easier to confirm that audio is reaching VoluBridge.
Mute button
Temporarily mutes the VoluBridge audio path. It is useful when checking output routing or level.
Peak / RMS meter
Peak shows short transient level. RMS shows average loudness. Use them to check level after volume or EQ changes.
Output
Output-related controls
The Mac output and the real output selected in VoluBridge have different roles.
Mac Output Device
This is the output selected in macOS. To use VoluBridge, select VoluBridge here. Mac audio first enters the VoluBridge virtual output.
Output from VoluBridge
This chooses the real device that receives audio from VoluBridge: an HDMI / DisplayPort monitor, USB DAC, built-in audio, or another output recognized by macOS.
Output CH
Selects the output channel pair on the real device. Most users use the default stereo pair. On multi-channel devices, confirm that the intended pair is selected.
Install Driver / Update Driver
Appears when VoluBridgeRT.driver is not installed or when the installed driver is older than the driver bundled with the app. Follow the prompt to install or update it.
Quit
Quits the menu bar app. The audio path is handled by the VoluBridgeRT driver, so audio can continue and saved settings remain in place after the app quits.
General Settings
General settings
Settings for daily behavior and window appearance.
Always on Top
Keeps the VoluBridge window above normal windows. Use it when you want to watch the meter or output selection while working.
Pin Window
Treats the window as a persistent control window and saves its position. Use it when you want VoluBridge to return to the same place and stay available.
Launch at Login
Starts VoluBridge automatically when you log in to your Mac. It is useful if you use an external monitor or USB DAC every day.
Show Virtual Devices
Shows virtual audio devices other than VoluBridge in the device list. Most users can leave this off. Enable it when combining VoluBridge with other virtual drivers.
Fine-grained Volume Steps
Makes keyboard volume changes smaller than the standard macOS step size. macOS Accessibility permission may be required the first time.
Apply to All Output Devices
Applies fine-grained volume steps beyond the VoluBridge output path. Most users only need fine steps when using VoluBridge; enable this when you want the same behavior across Mac outputs.
Display Refresh
Controls the refresh rate of meters and UI animation. Choose 12 / 24 / 48 / 60 FPS. Higher values feel smoother; lower values use less display work.
Power Saving
Chooses how long VoluBridge waits during silence before reducing display/internal activity. Options include 5 seconds, 30 seconds, 1 minute, 5 minutes, and Never.
Effect
Changes the window background style: Standard, HUD, Glass, or Dark. This is visual only.
Opacity
Adjusts how transparent the window background is. It helps when keeping VoluBridge visible while working in other apps.
Language
Selects the UI language. System follows macOS. English or Japanese forces that language.
Reset to Defaults
Restores settings to their default values. Use it when you want to undo display or behavior changes.
Uninstall Driver
Removes only VoluBridgeRT.driver. Use it when you want to reinstall the driver while keeping the app and license information.
Full Uninstall
Removes VoluBridge-related settings and driver components. Use it when cleaning up before reinstalling or ending use.
Optimizer
Optimizer
Tools for making each output easier to listen to.
OPTIMIZER title
Toggles Optimizer on and off. Turn it off when you do not want any intentional shaping.
Small red LEDs
Show left/right clipping. If they stay active, lower the volume or EQ gain slightly.
FLAT
Returns EQ to flat. Use it for comparison or when you want to start over.
BASS
Adds some low-end support. Useful for thin monitor speakers.
CLEAR
Brings out mid/high detail. Useful when sound feels muffled or hard to read.
VOCAL
Emphasizes speech-friendly ranges for meetings, videos, and streaming audio.
USER
Loads your saved setting. Option-click USER to save the current EQ as the USER preset.
7-band EQ
Adjusts 60 / 150 / 400 / 1k / 2.4k / 6k / 15k. Small adjustments usually work better than large moves.
Trial expired
After the 14-day trial ends, audio through the VoluBridge path is muted until a license is activated.
License
License area
Trial, purchase, and activation. Machine information is now included in RT Diagnostics.
Trial remaining
Shows how many days remain in the 14-day trial. Use the trial on your normal setup before purchasing.
Buy VoluBridge
Opens the purchase page. For personal use, the purchaser can use VoluBridge on up to 3 Macs they use. Business, team, or shared-device use requires one license per user.
Enter License Key
Enter the license key issued after purchase. The status changes to Licensed after activation succeeds.
Advanced
Advanced settings
Keep these at their defaults unless you are troubleshooting audio dropouts or validating a specific setup.
Sample Rate
The sample rate used by VoluBridgeRT. Choices include 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, and 192kHz. The default 48kHz is usually appropriate.
Fixed Target
The reference point used to read from the Producer timeline at the intended playback time. It treats latency as a fixed target instead of letting queued stock determine the delay.
Latency Mirror
Chooses the latency value reported to apps and macOS. Modes include None, Mirror Device, and Fixed Target. Most users should keep the default.
Reported Lat / Reported Saf
The Latency and Safety Offset values reported to apps. These are mainly for matching app expectations during validation.
Saf Offset
Controls Safety Offset handling. Auto(D) uses device information so the fixed target does not need to be increased unnecessarily.
Virtual Buffer / Device Buffer
Shows or controls the buffer view for the virtual path and the real output device. Useful when investigating dropouts or sync behavior.
Clock Tracking
Controls how VoluBridge follows the physical output device's timebase. Change it only while checking reproducible noise or dropout conditions.
PLL Correction / PLL Learning / Rate PLL / Phase PLL / PLL Strength
Compensation items for smoothing clock differences. Normal daily use should not require manual changes.
Sync Stabilization
Controls wait time around startup and device switching. Lock wait time and output-switch lock hold can help when a device needs more time to settle.
Diagnostics
RT diagnostics and developer items
These are mainly for troubleshooting and validation, not everyday operation.
RT Diagnostics
Shows sync state, driver state, latency, underflow, PLL, CPU load, Machine ID, and related values. Use it for troubleshooting or support reports.
Copy Diagnostics
Copies RT diagnostics to the clipboard, including Machine ID. Send it with your Mac model, macOS version, output device, and reproduction steps when reporting an issue.
Reset Stats
Resets diagnostic counters such as underflow counts. Use it when comparing behavior before and after a setting change.
Reset Learning
Resets learned PLL/sync state. Use it after changing output hardware or connection path during validation.
Cap Clear
Discards the current RT Cap stock once. It is mainly for sync validation.
Router Method
Developer-oriented internal routing modes such as Phase Follow, Fixed Target, Stock Overlap, and Timeline Only. Do not change it unless instructed.
Sync Capacity / Cap Auto Lead / Conceal Threshold
Experimental controls for stock, lead, and conceal behavior. Change them only for support or testing.
ReSnap and brief noise
When launching apps such as Cubase or Parallels Desktop while YouTube or Spotify is playing, VoluBridge may re-snap to follow the latency requested by the new app. After snap is established, noise is less likely to occur.
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