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If iZotope RX 12 shows a waveform but produces no sound, open Preferences > Audio, run Test Tone, and select the intended Driver Type and Output Device. If Test Tone is silent, troubleshoot the device, channel routing and operating-system output. If Test Tone works but the file is silent, troubleshoot the active tab, selection, transport, RX output gain and the file itself. RX Monitor is an alternative route through a running DAW, especially when that host owns the audio device during RX Connect.
Do not reinstall RX first. A no-audio fault can sit in the recording, selection, transport, RX mixer, driver, hardware routing, DAW or operating system. Change one part of that path at a time and keep the result of each test. This guide covers the standalone Audio Editor in RX 12 Standard and Advanced; Elements contains plug-ins, without the Audio Editor. For an RX effect inside a DAW, start with the plug-in section below.
RX no-audio symptoms at a glance
| What you see | First test | Likely branch |
|---|---|---|
| Playhead does not move | Known-good file, clear selection, click transport Play | File/transport or a device that failed to open |
| Playhead moves, RX meters do not | Audition whole time range and another file | Empty/filtered selection or file content |
| RX meters move, no sound | Preferences Test Tone and Output Device | Driver, routing, interface or OS output |
| Test Tone is also silent | Rescan/reselect device; verify channel pair | Device ownership or routing |
| Sound is thin, crackling or distorted on Windows | Buffer, sample rate, Windows enhancements | Driver/settings conflict |
| RX is silent only while DAW/RX Connect is active | Close DAW once, then test RX | Possible device-sharing conflict; consider RX Monitor |
| Only one file contains gaps | Play it outside RX and inspect waveform | Recorded dropout, not global playback |
| RX freezes instead of playing | Open a short WAV and remove heavy preview load | Performance troubleshooting |
Save first and record the exact symptom
Keep the original audio untouched and use File > Save RX Document to retain your edits before changing hardware settings. The RX saving guide distinguishes this from ordinary Save, which overwrites an opened WAV or AIFF. Write down the current Driver Type, Output Device, buffer and sample rate. Note whether the playhead moves, whether RX meters move, whether a Test Tone works and whether another application can play through the same speakers. That five-line record prevents circular troubleshooting.
Separate “no sound” from “bad sound.” Complete silence, choppy playback, half-speed audio, crackling and a thin phasey output are different failures. The official iZotope Windows audio-issue article specifically scopes its enhancement advice to thin, crackling or distorted sound; it is not proof that every silent Mac or interface needs the same change.
Prove the file contains audible audio
Open a short, known-good WAV that plays correctly elsewhere. Use an ordinary PCM file rather than a complex video container or network location. If it plays in RX, the global output path is working and the original file needs investigation. If both files fail identically, check the common playback settings as well as the device/driver branch; two silent files alone do not prove a hardware fault.
Confirm the active tab. RX can hold several files, and the visible tab may not be the source you expect. Inspect the waveform and meters. If the waveform is flat, the file may contain silence. If only one channel carries audio, the output may be routed to a hardware channel you are not monitoring.
For import, channel and export fundamentals, use the RX file workflow. Do not convert or overwrite the only copy merely to test playback.
Clear the selection and test the transport
Stop module Preview and click in an audible part of the waveform. Use ordinary Play for this test. The RX transport manual distinguishes Play from Play Selection Only: the latter restricts playback to the selected time and frequency range, so a narrow band or blank gap can sound silent. Also check Preferences > Misc > Play only selected channels if you selected a quiet channel. Make sure Record is not armed: when it is, Play starts recording instead of ordinary file playback.
Watch the playhead and meters separately. If neither moves, check the transport and any device-open error; an unavailable device can also prevent playback from starting. If the playhead moves and meters show activity, RX is producing a signal and the fault is downstream. If the playhead moves but meters stay flat, return to the file, tab, selected channel and time-frequency range.
Run the RX Test Tone
The current RX 12 Preferences manual documents a Test Tone inside Audio Preferences. It can generate tones or noise and includes channel identification. Lower the hardware listening level first. Set a modest Test Tone Volume, choose its Type, enable it, and raise the listening level gradually. Channel Identification helps identify output channels. Disable the tone after the test before returning to the file.
If Test Tone works: the tested driver and output route can reach your speakers at that moment; this does not prove every file channel or monitoring mode is routed correctly. Return to the file, selection, channel and transport. Check RX Output Gain and Composite View gain reduction. Do not dismantle a working interface route.
If Test Tone is silent: stay in Audio Preferences. Verify Driver Type, Output Device, Channel Routing and the hardware mixer. The problem is not specific to one audio file.
Select the correct Driver Type and Output Device
RX 12 lists driver types such as CoreAudio on macOS, ASIO on compatible Windows systems and RX Monitor for playback through a DAW. Choose the driver that belongs to the hardware you intend to use. Then select the actual speakers, audio interface or headphones under Output Device. Headphones plugged into an interface normally use that interface and its headphone routing; they need not appear as a separate computer output.
If you connected USB headphones, a dock or an interface after opening RX, use Device Refresh in Audio Preferences. Reselect the device after Bluetooth reconnects or the interface power-cycles. A system may switch its default output while RX keeps a previous explicit device.
Change one field, apply it and rerun Test Tone. If RX reports that the selected device cannot be opened, close applications that may own it before choosing random drivers. Record the original selection so you can return to it. Check Input Device too, especially if the error names an input. A March 2026 WaveLab forum report describes RX 10 playback recovering after an unused input was set to No audio device. That is a historical user report, not a verified RX 12 fix: test an available no-input option only for playback, and restore the input before recording. With a manufacturer ASIO driver, use its own input/output device pairing; do not assume an interface input can be combined with the laptop speakers.
Check Channel Routing and the hardware mixer
For ASIO and CoreAudio, RX provides a Channel Routing dialog, including multichannel output. Confirm that left and right playback are assigned to the physical pair connected to your monitors or headphones. An interface with outputs 1–8 can meter normally in software while RX sends to an unmonitored pair.
Then inspect the interface's own mixer or control application. Confirm computer playback reaches the monitor or headphone bus, the hardware mute is off, and the headphone level is up. Manufacturers use different names, so do not copy a routing label from another interface.
Use Test Tone's channel identification to prove left and right separately. If one side works, the driver is open; concentrate on channel assignment, cable and monitor control rather than reinstalling RX.
Check RX Output Gain and Composite View gain
RX Output Gain changes playback level nondestructively. Confirm it is not pulled down far enough to appear silent. If the failure occurs only in Composite View, inspect its separate gain-reduction preference. Compare the same file in an ordinary tab.
If silence occurs during a module Preview, use its Bypass or stop Preview and test ordinary Play. RX Plug-in Hosting loads one plug-in at a time; it is not a permanently active DAW-style output chain. A gate or other processor can silence its preview. Some modules also have Listen, which auditions removed material instead of the processed result. Preview Bypass does not undo Render: compare a rendered change with History or an untouched copy.
Resolve sample-rate, clock and buffer conflicts
Use Configure Driver when available to open the manufacturer's panel. Check the device's supported rate, clock source and any explicit rate error against the active DAW configuration. Do not assume every difference between a file rate and a hardware rate requires converting the file. Stop playback before testing a supported hardware setting, and avoid changing the clock while another application is using that device.
Buffer size is mainly a stability control. The Preferences manual says smaller buffers reduce latency but use more CPU; larger buffers reduce CPU demand and increase latency. If sound is choppy, increase the buffer one step and retest. A larger buffer is not the primary explanation for complete silence when Test Tone never reaches the device.
Do not apply old version-specific bug advice to RX 12. Confirm the installed version and current requirements in the RX 12 release notes before updating software or drivers.
Release competing audio applications
Close the DAW, video editor, conferencing app and browser media one at a time, testing RX after each change. On Windows, an exclusive-mode application or ASIO client may own the hardware. On either platform, recheck the chosen device and channel mapping after reconnecting hardware.
RX's “Release when not in use” option closes the audio device when playback stops so another application can use it. The manual notes that disabling the option may help when RX playback itself is not responsive enough. Test both behaviors deliberately; there is no universally correct setting for every shared-device workflow.
If closing the DAW restores RX, that points to an interaction between applications; it does not identify exclusive ownership with certainty. Check the driver's sharing policy and session settings. Focusrite's Scarlett guidance for losing audio when switching Windows apps identifies exclusive access as one possible cause. For a workflow that needs both RX and the DAW open, test RX Monitor.
Route RX through the DAW with RX Monitor
The current RX Monitor manual describes routing Audio Editor playback into a host. Available with Standard and Advanced, it is particularly useful when a DAW monopolizes the driver during RX Connect. It can also be useful whenever you deliberately want to listen through the host's monitoring route; an exclusive-access error is not a prerequisite.
- Create an Aux or Instrument track with an audible output to your monitors; use the host-specific track type below where required.
- Insert iZotope RX Monitor on that track.
- In RX standalone, open Preferences > Audio.
- Choose RX Monitor as Driver Type.
- Check that the RX Monitor plug-in changes from Disconnected to Connected. Play RX, then follow the host track meter, mute/solo, fader and output bus to the hardware.
The host-specific RX Monitor support guide specifies an FX Track for Cubase and Nuendo. In Reaper, Options > Preferences > Audio must not close the audio device when stopped and inactive for this workflow. If Monitor remains Disconnected, verify the loaded plug-in and RX Driver Type before troubleshooting the host fader. When you finish using the DAW route, select the normal audio driver again in RX; leaving RX Monitor selected without an active host instance cannot provide ordinary standalone output.
For the complete send, repair, monitor and return sequence in that host, follow the RX Connect in Pro Tools workflow and verify each handoff before processing the next clip.
If the audio never arrived in RX or will not return to the DAW, use the separate RX Connect troubleshooting guide. Transfer and playback are separate stages.
Check the operating-system output path
On Windows, an application can be assigned to a different output from the system default. Microsoft's per-app audio guide covers the case where system sounds work but one application does not. For an RX route using Windows system audio, check Settings > System > Sound > Volume mixer for the app's output assignment and mute state. If RX uses ASIO, use RX and the interface controls instead: ASIO bypasses the Windows audio system, so its playback is not controlled by the per-app Windows mixer. Focusrite's ASIO/WDM explanation also describes the input/output pairing constraint. The broader Windows audio troubleshooting path covers output selection, drivers and enhancements.
On macOS, verify the active device and output level in the current Sound output settings. Then return to RX and explicitly select the intended CoreAudio output. Use the interface's own controls where the OS offers no output-volume adjustment. Plugging in headphones or waking a dock can change the OS path without updating every open application.
For a Windows system-audio route, test enhancements only after confirming output selection and mute. iZotope discusses thin or distorted playback; Microsoft also lists enhancements as a possible cause of complete silence. Compare one change, and restore it if it does not help. This is not a substitute for checking an ASIO interface route. Do not change every enhancement, sample rate and driver simultaneously.
If only an RX plug-in is silent inside the DAW
Confirm the track itself plays when the RX plug-in is bypassed. Check track mute/solo, input monitoring, insert bypass, region gain and output bus. Then load the plug-in on a known-good track. If the plug-in is not listed at all, this is discovery rather than playback; use RX plug-ins not showing.
If one heavy module adds latency or causes dropouts, verify host delay compensation and supported plug-in format. The RX AU, VST3, AAX and ARA guide maps the formats and host boundaries. Do not use RX Monitor as an insert effect on the audio you are repairing.
Ten-step no-audio fix
- Protect the session and note the symptom. Keep the source untouched, save an RX Document, then record playhead/meter movement and whether other apps reach the output.
- Prove the file contains audible audio. Open a known-good WAV, choose the correct tab, stop module Preview and use ordinary Play with Record unarmed; check selection and channel restrictions.
- Run RX Test Tone. Start at a low listening level, enable a modest tone and check the route; disable it after testing. A working tone narrows the fault without proving every file channel.
- Select the correct driver and output device. Use Device Refresh and select the intended output; investigate Input Device too if the device-open error names it.
- Check channel routing and output gain. Verify hardware output pairs, interface monitoring and RX/Composite View playback gain.
- Resolve sample-rate and buffer conflicts. Check supported device/clock settings and explicit rate errors; increase the buffer for unstable playback without converting the source as a first fix.
- Release competing audio applications. Save the other application's work, close competing audio apps one at a time and retest; check sharing policy when the result points to a conflict.
- Use RX Monitor when listening through the DAW. Route RX to the appropriate host track, confirm Connected and verify the host output; restore the normal RX driver for standalone listening.
- Check the operating-system output path. For Windows system audio, check per-app output, mute and enhancements; for ASIO, check RX/interface controls. Verify the intended CoreAudio route on macOS.
- Update only after the fault is isolated. Verify support, update the relevant RX/device component and retest the same known-good file.
When to reset, update or reinstall
Reset preferences only after you have recorded the working/non-working settings and proven that the issue follows RX rather than the device. Update RX when the current release notes identify support or a relevant fixed defect. Update the interface driver when its own panel fails, the device cannot open across applications or the vendor requires a newer operating-system build.
Reinstall after a reproducible RX-only fault survives a known-good file, working OS output, correct driver/device, correct routing and a supported configuration. If RX crashes or freezes before playback, the RX crash guide owns logs, plug-in isolation and preference recovery.
What not to do
- Do not reinstall before testing RX Test Tone.
- Do not change driver, sample rate, buffer and OS output at once.
- Do not assume a visible waveform proves the output path works.
- Do not leave RX Monitor selected when you intend to listen without a running host Monitor instance.
- Do not apply RX 10-specific sample-rate bug advice to RX 12.
- Do not disable system enhancements without comparing the affected Windows symptom.
- Do not overwrite the source while troubleshooting.
- Do not confuse recorded dropouts with application-wide silence.
The Fix iZotope RX hub routes from silent playback to crashes, missing plug-ins, authorization, format and Connect failures.
Frequently asked questions
Why does RX show a waveform but play no sound?
The file can be open while RX is routed to the wrong driver, device or output pair. Run Test Tone: if it is silent, fix the device path; if it works, check the active tab, selection, channel and RX output gain.
Where is the output device setting in RX 12?
Open Preferences and choose the Audio tab. Select the Driver Type and Input/Output Device there, then use Channel Routing for ASIO, CoreAudio or multichannel hardware.
Why does RX play through speakers but not headphones?
The operating system or RX may still target the speakers. Connect and activate the headphones, verify the OS output, rescan devices in RX and explicitly choose the headphones or their interface output.
What is the RX Monitor plug-in for?
In Standard and Advanced, RX Monitor routes Audio Editor playback through an Aux or Instrument track in a host, with host-specific exceptions such as Cubase/Nuendo FX Tracks. It is especially useful for a DAW device-sharing conflict during RX Connect; the plug-in must show Connected. Restore the normal RX driver when listening without that host route.
What if RX Test Tone works but my file is silent?
The tested output route works at that moment. Check the active tab, audible file region, selected channels, Play versus Play Selection Only, Record arming and RX Output Gain. Stop module Preview or bypass its processing; compare rendered edits through History or an untouched file.
How do I fix “selected audio device cannot be opened”?
Record the error, save other work and test with competing audio applications closed. Use Device Refresh, select the correct driver and output, and check Input Device if the error names it. Verify supported clock/rate and routing in the interface panel; RX Monitor requires its host instance to be connected.
Can changing the buffer fix no audio in RX?
A larger buffer can help choppy or unstable playback by reducing CPU demand, but it is not the first fix for complete silence. Test Tone, device selection and routing come first.
Should I reinstall RX when playback stops?
Not first. Prove the file, Test Tone, driver, output device, routing and OS audio path. Reinstall only after the problem is reproducible in RX on a supported system while the same hardware works elsewhere.
