Prevents SPDIF/HDMI/Bluetooth digital audio playback devices from sleeping. Uses WASAPI, requires Windows 7+. It doesn't have GUI and starts to do its job right after the program is started. To make it autorun, copy the soundkeeper.exe into the startup directory that you can access by pressing Win+R and entering shell:startup. To close the program, run the soundkeeper.exe kill command or just kill its process.

Download: soundkeeper.7z (90KB). Source code →

The archive contains a few builds (you can remove unused ones):

• SoundKeeper64.exe is for x86-64 versions of Windows, most people need this version.
• SoundKeeper32.exe is for x86-32 versions of Windows, if you have a very old PC with 32-bit Windows.
• SoundKeeperARM64.exe is a native ARM64 build, if you have a new ARM based PC.

There is also a debug version that outputs all debug logs into a console window. Please provide the logs when you report issues.

Features

• Sound Keeper is fully automatic and doesn't require any user interaction.
• Supports keeping on multiple sound outputs (e.g. an SPDIF and an HDMI).
• Detects new sound outputs on the fly (e.g. when you connected a TV via HDMI).
• Supports various stream types that should help in all possible cases.

Settings

Default behavior can be changed by changing file name of the Sound Keeper executable (just add desired settings to the Sound Keeper file name) or by passing them as command line arguments. All settings are case insensitive.

Primary audio output is used by default. If current primary audio output has changed, the Sound Keeper detects this and switches to the new output automatically. If you want to run Sound Keeper on all enabled audio outputs, just add All to executable file name to enable Sound Keeper on all outputs.

All supported audio output type modes:

• Primary keeps on primary audio output only. It is used by default.
• All keeps on all enabled audio outputs.
• Digital keeps on all enabled SPDIF and HDMI audio outputs (like it was in Sound Keeper v1.0).
• Analog keeps on all enabled audio outputs except SPDIF and HDMI.

Inaudible stream of zeroes with infrequent smallest possible non-zero samples (fluctuations) is used by default. Add Zero to executable file name to use stream of zeroes only.

All supported stream types:

• OpenOnly opens audio output, but doesn't stream anything. Sometimes it helps if it's a driver only issue.
• Zero plays stream of zeroes. It may be not enough for some hardware.
• Fluctuate plays stream of zeroes with the smallest non-zero samples once in a second. Used by default.
• Sine plays 1Hz sine wave at 1% volume. The frequency and amplitude can be changed. Useful for analog outputs.
• White, Brown, or Pink play named noise, with the same parameters as the sine (except frequency).

If the default inaudible stream doesn't help, try the new Sine stream type. It generates a sine wave, and can be customized. There are two parameters: F (frequency) and A (amplitude). The value goes right after the parameter character. For example, add SineF10A5 to executable file name to generate 10Hz sine wave with 5% amplitude. Low frequencies (below 20Hz) and high frequencies (above 20000Hz) with low amplitude (up to 10%) are inaudible.

Stream parameters:

• F is frequency. Default: 1Hz for Sine and 50Hz for Fluctuate. Applicable for: Fluctuate, Sine.
• A is amplitude (i.e. volume). Default: 1%. If you want to use inaudible noise, set it to 0.1%. Applicable for: Sine, Noise.
• L is length of sound (in seconds). Default: infinite.
• W is waiting time between sounds if L is set. Use to enable periodic sound.
• T is transition or fading time. Default: 0.1 second. Applicable for: Sine, Noise.

Examples:

• SoundKeeperAll.exe generates default inaudible stream on all enabled audio outputs.
• SoundKeeperZero.exe generates zero stream on primary audio output.
• SoundKeeperAllZero.exe generates zero amplitude stream on all enabled audio outputs.
• SoundKeeperSineF10A5.exe generates 10Hz sine wave with 5% amplitude on primary audio output. It is inaudible.
• SoundKeeperSineF1000A100.exe generates 1000Hz sine wave with 100% amplitude. It is audible! Use it for testing.
• SoundKeeper.exe sine -f 1000 -a 100 is command line version of the previous example.
• SoundKeeper.exe brown -a 0.1 generates brown noise with 0.1% amplitude.

What's new in v1.3.4

• Tune the Windows 8-10 WASAPI memory leak workaround to make it working for longer time.
• Native ARM64 build (with statically linked runtime hence the bigger binary).
• [2024/11/12] Added digital signature.

What's new in v1.3.3

• Fixed arguments parsing bug: All or Analog after specifying stream type led to amplitude set to 0.

What's new in v1.3.2

• Fluctuate treats 32-bit PCM output format as 24-bit since WASAPI reports 24-bit as 32-bit for some reason.
• Fluctuate generates 50 fluctuations per second by default. It helps in many more cases.
• Sound Keeper doesn't exit when it is muted.

What's new in v1.3.1

• A potential deadlock when audio devices are being added or removed has been fixed.
• Fluctuate treats non-PCM output formats (like Dolby Atmos) as 24-bit instead of 16-bit.
• Frequency parameter F is limited by half of current sample rate to avoid generation of unexpected noise.
• More detailed logs in debug build. Debug output is flushed immediately, so it can be redirected to a file.

What's new in v1.3.0

• Fluctuate is 1 fluctuation per second by default. Frequency can be changed using the F parameter.
• Periodic playing of a sound (parameters L and W) with optional fading (parameter T).
• New White, Brown, and Pink noise signal types.
• Self kill command is added. Run soundkeeper kill to stop running Sound Keeper instance.
• Analog switch was added. It works as the opposite of Digital.
• Ignores remote desktop audio device (this feature can be disabled using the Remote switch).
• New OpenOnly mode that just opens audio output, but doesn't stream anything.
• New NoSleep switch which disables PC sleep detection (Windows 7-10).
• Work as a dummy when no suitable devices found.
• Sound Keeper shouldn't prevent PC from automatic going into sleep mode on Windows 10.
• The program is not confused anymore when PC auto sleep is disabled on Windows 10.
• The workaround that allowed PC to auto sleep had to be disabled on Windows 11.

Sound Keeper vs. SPDIF Keep Alive vs. SPDIF-KA

	Sound Keeper v1.3	SPDIF Keep Alive v1.2	SPDIF-KA v1.4
Fully automatic:	Yes	No	No
Multiple outputs:	Yes	No	No
Stream types:	7	2	2
Periodicity:	Yes	No	No
GUI:	No	Yes	Yes
Requires .NET:	No	Yes	Yes
Executable size:	20KB	668KB	163KB
CPU usage (on Intel Core i5 4460):	0.004%	0.06%	0.06%
RAM usage (Private Working Set):	1636KB	13704KB	10600KB

Known issue: streaming audio prevents automatic sleep mode

When a program streams any audio (even silence), the system doesn't go into sleep mode automatically after specified time of inactivity. Sound Keeper uses the NtPowerInformation(SystemPowerInformation, ...) function to retrieve time when system is going to sleep, and disables itself right before this time. On Windows 7, it works perfectly. Windows 10 waits for 2 minutes more after any sound was streamed, so the PC goes into sleep mode after 2 minutes when Sound Keeper disabled itself. For some reason, Windows 11 always reports that the system is going to sleep in 0 seconds. So, the workaround had to be disabled on this OS until a better solution is found. You can try to use the powercfg to workaround this issue at the system level. Details →