Build audacity with ASIO support on Windows

README.md

Build your own Audacity for Windows with ASIO driver support

Note, if you have come here from a video the instructions for installing the tools have now changed.

Due to licensing rules Audacity cannot provide a prebuilt version with ASIO support. But you can build your own and this guide makes it easy for you to do so.

Note that this builds Audacity 3.1.2. Audacity 3.0.0 introduced a new project file format so you will hit compatability problems if you try to use Audacity 2.x.x to open projects saved with this version.**

The Audacity program is the "go to" solution for many audio recording and editing tasks. However, unlike many more advanced DAWs, it doesn't support Windows ASIO drivers "out of the box". Fortunately, Audiacity's standard MME support is fine for most uses. That said, common reasons for needing ASIO are using digital audio or music equipment that only comes with ASIO drivers, such as Behringer mixers (which actually use the ASIO4ALL ASIO <> WDM bridging driver). Another common reason is to take advantage of the low latency or multiple channels supported by ASIO.

While it is possible to build your own Audacity with ASIO support this usually requires considerable technical skills.

To reduce this requirement, the instructions provided here make it easy to build your own version of Audacity with ASIO support on a Windows PC. The instructions for the few manual steps should be straight forward to follow. A script checks everything is installed and builds a 64 bit release version of Audacity for you.

NB. If you do use this to build Audacity with ASIO support you must not redistribute it due to the ASIO SDK licensing terms - see below.

Unfortunately, it turns out the Audacity ASIO build has limited multi channel support. For example, the peak meters always show channels 1 & 2 and to record channels 3 & 4 requires recording 1, 2, 3 & 4. So While Audacity still works really well for simple recording tasks, you might want to eventually switch to a full DAW with AISO support. I'll probably use Reaper.

Here's a brief blog post explaining why I needed ASIO and it includes a screen shot.

Since writing that, I discovered my McMillen K-Mix digital interface mixer facilities alow routing of inputs 3 & 4 to the main outputs on 1 and 2 so can use the default MME Audacity build after all. For playback from PC, I found the HiFi Driver and ASIO Bridge from VB Audio lets me re-route PC audio out to channels 3 & 4 on the K-Mix, Leaving Channels 1 & 2 free for instruments and Mics.

Licensing

The reason for Audacity's lack of ASIO support is licensing, not technical. Steinberg do not alow the ASIO SDK to be redistributed (as required by open source projects). In addition, Audacity is GPL licensed and so is incompatible with the ASIO SDK licence redistribution rules.

Detailed instructions

Note for developers: These instructions assume a clean dev. env. If you have existing installations of the tools you may hit errors due to differing versions. Perhaps use a VM (difficult with Windows licencing) or a Windows container.

This video by @Renamesk walks you through the process, but the tool installation method has changed.

• ensure you have a PC with modern Windows installed. 11 and 10 are known to work but 7 and 8 should too.
• install "Git For Windows" - click the "download" button.
• make a new folder C:\projects
• click on the 'raw' button at the top of the script (below) in this Gist.
• use the browser Save As feature to save the script as \projects\build-audacity.cmd (be careful there's no ".txt")
• open a new Windows cmd terminal (Windows + R keys and then type cmd)
• type cd \projects and enter key
• install required tools by typing build-audacity.cmd --install and enter.
  • NB for Visual Studio, make sure you check the "desktop development with C++" workload
  • if you have a non English Windows or Visual Studio then you must also install the VS English language pack.
• when the install completes open a cmd temrinal again and start the build by typing build-audacity.cmd and enter.
• come back later - it will take at least 10 minutes
• Audactiy will be launched to test it was built correctly
  • to it run again see the program location printed out at the end of the build
  • or copy the specified folder to where you want to run Audacity from, optionally renaming it

If you have any ASIO drivers installed you should find ASIO is now available in the the Audacity driver selection combo box.

When things go wrong

As with any complex software build there are many moving parts (including Windows itself) and things can sometimes go wrong. Here are some tips if you hit build errors.

• make sure you have latest script
• run the script with --cleanall and try again
• uninstall all the tools (Python, cmake, Visual Studio and its installer) and then reboot before trying again
  • note having other versions of any of the tools installed may well cause problems - remove them
• read the error output - clues are often buried in reams of impenetrable text
• disable any Anti Virus - the built-in Microsoft one is usually not a problem

Thanks

• @diogodh for finding and fixing the bug with conan installations
• The Audacity team for an fantastic audio tool.

build-audacity.cmd

@echo off
rem See https://wiki.audacityteam.org/wiki/Building_On_Windows
rem Build audacity with ASIO support on Windows
rem See the following gist for details of what ot install etc
rem  https://gist.github.com/SteveALee/da24c2be633340b8791066dd98eb5d0b
rem
rem Options (only one may be specified)
rem
rem --install - install tools
rem --clean - remove built files
rem --cleanall - remove fetched and built files
rem --getonly - only get the files 
rem --noget - don't fetch again from git
rem --gui - run cmake-gui
rem
rem MIT licence
rem steve@opendirective.com

SETLOCAL
set AUDACITY_REL=3.1.2
set VISUALSTUDIOVER=2019\Community
set VSDIR=%ProgramFiles(x86)%\Microsoft Visual Studio\%VISUALSTUDIOVER%
set PROJROOT=C:\projects
set AUDACITY=%PROJROOT%\audacity
set AUDACITY_BUILD=%PROJROOT%\audacity-asio
set EXEDIR=%AUDACITY_BUILD%\bin\Release

rem check projroot exists
if /I not [%~dp0] == [%PROJROOT%\] (
  echo.
  echo Error: This script must be run in %PROJROOT% - see %%PROJROOT%% in file
  echo.
  if not exist %PROJROOT% (
    echo Create %PROJROOT
    goto exit
) else (
  echo cd to %PROJROOT%
  goto exit
)
)

if not [%1] == [--install] goto clean
rem Get tools
rem ANSI escape sequences do not work in if () block so we use goto

set cmake-url=https://github.com/Kitware/CMake/releases/download/v3.22.0/cmake-3.22.0-windows-x86_64.msi
set vs2019-url=https://aka.ms/vs/16/release/vs_community.exe
set python-url=https://www.python.org/ftp/python/3.10.0/python-3.10.0-amd64.exe

echo 
echo.
echo Fetching tools..
echo 

mkdir bin 2> :null
curl -L %cmake-url% -o bin\cmake.msi
curl -L %vs2019-url% -o bin\vs.exe
curl -L %python-url% -o bin\python.exe

echo 
echo.
echo Installing tools...
echo.
echo IMPORTANT!! Follow the instructions below for each installer
echo Close each installer when it is done
echo.
echo CMake: make sure you select "add cmake to system PATH" 
pause
bin\cmake.msi
echo Visual Studio: make sure you check the "desktop development with C++" workload 
pause
bin\vs.exe
echo Python: make sure you select "add python 3.10 to the PATH"
pause
bin\python.exe

echo.
echo This window will now close!
echo Open another "cmd" window (Wnd + R, cmd) and run "%0" again to build Audactity
echo 
echo.
Pause
exit

:clean

if not [%1] == [--getonly] (
  if /I [%1] == [--clean] echo Cleaning built files... & rmdir /s/q %AUDACITY_BUILD% 2> :null
  if /I [%1] == [--cleanall] echo Cleaning source and built files... & rmdir /s/q %AUDACITY% %AUDACITY_BUILD% 2> :null
  if /I [%1] == [--cleanall] where /q conan & if ERRORLEVEL 0 echo Cleaning conan modules... & conan remove -f * 2> :null
)

rem Launch cmake-gui
if [%1]==[--gui] cmake-gui -Daudacity_has_asio_support=On -DAUDACITY_BUILD_LEVEL=2 -S %AUDACITY% -B %AUDACITY_BUILD% & goto build

rem ensure tools are installed 
if not [%1] == [--getonly] (
  rem NB this sets 64bit arch for cmake
  if not exist "%VSDIR%\VC\Auxiliary\Build\vcvars64.bat" echo Error: Install Visual Studio %VISUALSTUDIOVER% & goto exit /b 
  if not defined VisualStudioVersion call "%VSDIR%\VC\Auxiliary\Build\vcvars64.bat"
  where /q cmake & if ERRORLEVEL 1 echo Cmake does not appear to be installed & goto exit /b
  where /q conan & if ERRORLEVEL 1 pip install conan & if ERRORLEVEL 1 echo Python does not appear to be installed & goto exit /b
)

rem Get source code
set getsrc=0
if /I [%1] == [] set getsrc=1
if /I [%1] == [--getonly] set getsrc=1
if /I [%1] == [--cleanall] set getsrc=1
if /I not [%1] == [--noget] ( 
  where /q git & if ERRORLEVEL 1 echo Error Install Git for Windows. Choose the option "Git from the command line" && goto exit /b
  if [%getsrc%] == [1] (
    echo.
    echo Fetching code for Audacity %AUDACITY_REL%...
    echo.  
    git clone -b Audacity-%AUDACITY_REL% --depth 1 https://github.com/audacity/audacity/ %AUDACITY%
    if ERRORLEVEL 1 echo Error: cannot fetch the Audacity code. Try the --cleanall or --noget options & goto exit
    if not exist %AUDACITY%\CMakeLists.txt echo Something is wrong with %AUDACITY% files & goto exit
 )
)

if /I [%1] == [--getonly] goto exit

echo.
echo Building Audacity %AUDACITY_REL% 64 bit release with ASIO support...
echo.
    
cd %AUDACITY%
cmake -G "Visual Studio 16 2019" -DCMAKE_CONFIGURATION_TYPES=Release -Daudacity_has_asio_support=On -DAUDACITY_BUILD_LEVEL=2 -S %AUDACITY% -B %AUDACITY_BUILD% & if ERRORLEVEL 1 echo Error: Cannot create Audacity buildfiles & goto exit
:build
cd %AUDACITY_BUILD%
set msbuild="%VSDIR%\MSBuild\Current\Bin\MsBuild.exe"
%msbuild% audacity.sln -t:Audacity -p:configuration=Release
if ERRORLEVEL 1 echo Error: cannot build Audacity & goto exit

cd %PROJROOT%

rem All done
echo 
echo.
echo Congratulations!
echo Your new Audacity with ASIO support will now launch.
echo In future just run the audacity.exe. No need to install.
echo.
echo    %EXEDIR%\audacity.exe
echo.
echo Or copy the folder 
echo.
echo    %EXEDIR%\ 
echo.
echo and run the included audacity.exe
echo.
echo 
    
start %EXEDIR%\audacity.exe

:exit
cd %PROJROOT%
ENDLOCAL

@Giermann thanks very much! Very much appreciated as swamped right now.

In theory curl always comes with Win 10, 11. I checked but can't recall my source. Dunno about win ARM but I'm assuming not relevant here.

Is it possible another curl installed? Hence asking about any dev tools. Does it have permission to write to bin folder? Errors should be printed as

@SteveALee I am not sure, but I guess with "smth" he just tried to abbreviate "something".

@sank1337 Error messages about certificates are often related to a wrong setting of the system clock, did you check your date and time settings? Sadly it's months ago that I last used or modified Steve's Script - but your main problem seems to be "curl". I don't know if it is always included in Windows or which version you are running. Maybe you are already successful, if you just skip the certificate revocation (which fails according to the error message).

You can try to modify lines 99-101 and add the parameter "--ssl-no-revoke":

curl --ssl-no-revoke -L %git-url% -o %INSTALLFILEDIR%\g4w.exe
curl --ssl-no-revoke -L %vs2022-url% -o %INSTALLFILEDIR%\vs.exe
curl --ssl-no-revoke -L %python-url% -o %INSTALLFILEDIR%\python.exe

Ye its workin thank you guys

What fixed it? no-revoke?

I think so, because the error was exactly "The revocation function was unable to check revocation for the certificate."

But I would not add this switch for everyone, as it reduces security.

What fixed it? no-revoke?

Yes

Great. I've never ever seen in years of curl use. Lol. As @Giermann said, is your system time off?

But I would not add this switch for everyone, as it reduces security.

Defo not! It's indicative of a system problem IMHO.

Thanks again! Another happy ASIO user 😀

Updated Python and Git for WIndows versions (Visual Studio is always latest)

Trying to build v3.1.3 (last version that you can reset the peak and clip marks in the meter with stopping play) which fails. console output:

**********************************************************************

** Visual Studio 2022 Developer Command Prompt v17.14.16
** Copyright (c) 2025 Microsoft Corporation
**********************************************************************
[vcvarsall.bat] Environment initialized for: 'x64'
WARNING: Package(s) not found: conan
conan 2.11.0 not found
WARNING: Skipping conan as it is not installed.
installing conan 2.11.0
Collecting conan==2.11.0
  Downloading conan-2.11.0.tar.gz (476 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Collecting requests<3.0.0,>=2.25 (from conan==2.11.0)
  Downloading requests-2.32.5-py3-none-any.whl.metadata (4.9 kB)
Collecting urllib3<1.27,>=1.26.6 (from conan==2.11.0)
  Downloading urllib3-1.26.20-py2.py3-none-any.whl.metadata (50 kB)
Collecting colorama<0.5.0,>=0.4.3 (from conan==2.11.0)
  Downloading colorama-0.4.6-py2.py3-none-any.whl.metadata (17 kB)
Collecting PyYAML<7.0,>=6.0 (from conan==2.11.0)
  Downloading pyyaml-6.0.3-cp313-cp313-win_amd64.whl.metadata (2.4 kB)
Collecting patch-ng<1.19,>=1.18.0 (from conan==2.11.0)
  Downloading patch-ng-1.18.1.tar.gz (17 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Collecting fasteners>=0.15 (from conan==2.11.0)
  Downloading fasteners-0.20-py3-none-any.whl.metadata (4.8 kB)
Collecting Jinja2<4.0.0,>=3.0 (from conan==2.11.0)
  Downloading jinja2-3.1.6-py3-none-any.whl.metadata (2.9 kB)
Collecting python-dateutil<3,>=2.8.0 (from conan==2.11.0)
  Downloading python_dateutil-2.9.0.post0-py2.py3-none-any.whl.metadata (8.4 kB)
Collecting MarkupSafe>=2.0 (from Jinja2<4.0.0,>=3.0->conan==2.11.0)
  Downloading markupsafe-3.0.3-cp313-cp313-win_amd64.whl.metadata (2.8 kB)
Collecting six>=1.5 (from python-dateutil<3,>=2.8.0->conan==2.11.0)
  Downloading six-1.17.0-py2.py3-none-any.whl.metadata (1.7 kB)
Collecting charset_normalizer<4,>=2 (from requests<3.0.0,>=2.25->conan==2.11.0)
  Downloading charset_normalizer-3.4.3-cp313-cp313-win_amd64.whl.metadata (37 kB)
Collecting idna<4,>=2.5 (from requests<3.0.0,>=2.25->conan==2.11.0)
  Downloading idna-3.10-py3-none-any.whl.metadata (10 kB)
Collecting certifi>=2017.4.17 (from requests<3.0.0,>=2.25->conan==2.11.0)
  Downloading certifi-2025.8.3-py3-none-any.whl.metadata (2.4 kB)
Downloading colorama-0.4.6-py2.py3-none-any.whl (25 kB)
Downloading jinja2-3.1.6-py3-none-any.whl (134 kB)
Downloading python_dateutil-2.9.0.post0-py2.py3-none-any.whl (229 kB)
Downloading pyyaml-6.0.3-cp313-cp313-win_amd64.whl (154 kB)
Downloading requests-2.32.5-py3-none-any.whl (64 kB)
Downloading charset_normalizer-3.4.3-cp313-cp313-win_amd64.whl (107 kB)
Downloading idna-3.10-py3-none-any.whl (70 kB)
Downloading urllib3-1.26.20-py2.py3-none-any.whl (144 kB)
Downloading certifi-2025.8.3-py3-none-any.whl (161 kB)
Downloading fasteners-0.20-py3-none-any.whl (18 kB)
Downloading markupsafe-3.0.3-cp313-cp313-win_amd64.whl (15 kB)
Downloading six-1.17.0-py2.py3-none-any.whl (11 kB)
Building wheels for collected packages: conan, patch-ng
  Building wheel for conan (pyproject.toml) ... done
  Created wheel for conan: filename=conan-2.11.0-py3-none-any.whl size=605064 sha256=f76c2315586abe8171a896a0d5bb7678c33f6c988bbba5de5d50d697e20690ad
  Stored in directory: c:\users\wdagutilityaccount\appdata\local\pip\cache\wheels\49\1c\ae\574ab6751ca209d70480efab240b4c28b06658a4089c325bb5
  Building wheel for patch-ng (pyproject.toml) ... done
  Created wheel for patch-ng: filename=patch_ng-1.18.1-py3-none-any.whl size=17028 sha256=c614f7348fadbf6fdf89b1e35e65da64942d63b88af72d8186ec9b817d36e92d
  Stored in directory: c:\users\wdagutilityaccount\appdata\local\pip\cache\wheels\43\44\12\fd3f7633c824273d14b9a7ddee20d0b59e354ef6f6b9fe8ce1
Successfully built conan patch-ng
Installing collected packages: urllib3, six, PyYAML, patch-ng, MarkupSafe, idna, fasteners, colorama, charset_normalizer, certifi, requests, python-dateutil, Jinja2, conan
Successfully installed Jinja2-3.1.6 MarkupSafe-3.0.3 PyYAML-6.0.3 certifi-2025.8.3 charset_normalizer-3.4.3 colorama-0.4.6 conan-2.11.0 fasteners-0.20 idna-3.10 patch-ng-1.18.1 python-dateutil-2.9.0.post0 requests-2.32.5 six-1.17.0 urllib3-1.26.20
Fetching code for Audacity 3.1.3...

Cloning into 'C:\projects\audacity'...
remote: Enumerating objects: 4916, done.
remote: Counting objects: 100% (4916/4916), done.
remote: Compressing objects: 100% (3942/3942), done.
remote: Total 4916 (delta 1025), reused 3012 (delta 760), pack-reused 0 (from 0)
Receiving objects: 100% (4916/4916), 48.51 MiB | 16.01 MiB/s, done.
Resolving deltas: 100% (1025/1025), done.
Note: switching to 'ff6d6739fbe73de9c9ad3aa4e07642653604af44'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

Updating files: 100% (5720/5720), done.
-- Selecting Windows SDK version 10.0.26100.0 to target Windows 10.0.22621.
-- The C compiler identification is MSVC 19.44.35217.0
-- The CXX compiler identification is MSVC 19.44.35217.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Conan: Adding audacity remote repository (https://artifactory.audacityteam.org/artifactory/api/conan/conan-local) verify ssl (True)
usage: conan remote [-h] [-v [V]] [-cc CORE_CONF] {add} ...
conan remote: error: unrecognized arguments: True
ERROR: Exiting with code: 2
CMake Error at cmake-proxies/cmake-modules/conan.cmake:851 (message):
  Conan remote failed='2'
Call Stack (most recent call first):
  cmake-proxies/cmake-modules/AudacityDependencies.cmake:6 (conan_add_remote)
  CMakeLists.txt:175 (include)


-- Configuring incomplete, errors occurred!
Error: Cannot create Audacity buildfiles

C:\Projects>

Using Win11 sandbox
Builds latest version fine

Please help, TIA

@The-Real-Rustla ah, the build process changed over time and supporting old version builds would be very much work. The script does try to handle some conan version differences but seems it breaks here. :(

I do understand your frustrations with recent audacity versions so I will try to take a look soon.

@The-Real-Rustla The build process has change too much since 3.1.x for the script to support it. All I can suggest is you try building it yourself followingt the projetc build instructions https://github.com/audacity/audacity/blob/Audacity-3.1.3/BUILDING.md

Just command line: In C:\Projects build-audacity.cmd -v3.1.3 In a Windows 11 23H2 sandbox

…

On Thu, 2 Oct 2025, 9:35 pm Steve Lee, ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ @The-Real-Rustla <https://github.com/The-Real-Rustla> please explain how exactly you are trying to build old version. Eg command line. — Reply to this email directly, view it on GitHub <https://gist.github.com/SteveALee/da24c2be633340b8791066dd98eb5d0b#gistcomment-5784211> or unsubscribe <https://github.com/notifications/unsubscribe-auth/APEPOZYHO3KY5XCOIWRLXQL3VTPV7BFHORZGSZ3HMVZKMY3SMVQXIZNMON2WE2TFMN2F65DZOBS2WR3JON2EG33NNVSW45FGORXXA2LDOOIYFJDUPFYGLJDHNFZXJJLWMFWHKZNJGEYDEMBTGUYDKONKMF2HI4TJMJ2XIZLTSOBKK5TBNR2WLJRWGE4DSMRSURXGC3LFVBQWG5DPOJPWSZECUV3GC3DVMWSHI4TVMWSG4YLNMW5XI2DSMVQWIX3QMFZHI2LDNFYGC3TUL5QWG5DJOZUXI6MCUV3GC3DVMWSGO2LTOSSG4YLNMWVXI2DSMVQWIX3UPFYGK> . You are receiving this email because you were mentioned. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub> .

Good, but just too old a version for the script. Please see comment above.

Good, but just too old a version for the script. Please see comment above.

Sorry, replied by email to the unedited response.

I did build 3.0.2 manually years ago, so I will give 3.1.3 a go manually too.

Thanks for your work on this script anyway, going forward I'm sure I will use it, especially when/if you update it for the 4.x.x version when it gets released, as they promised that this will have the reset of the metering peaks issue sorted in that. (only took 5 sub versions or a few years). Or will it work with the pre release V4?

especially when/if you update it for the 4.x.x version

@The-Real-Rustla i was just thinking about that. I guess it depends on what i think of 4 and how complex build is. I spend less time coding these days.

Thanks for your feedback. 😀

@The-Real-Rustla you might be in luck as I recalled gists are actually git repos and I dug out the script version for 3.1.2. I tried it but it falls over with a conan error. That might just be coz I don't have a really clean dev env. DM me and I'll send you the script to try if you like.

He can also just search for it himself by clicking on "Revisions" on top and scroll through the changes.
Last version for 3.1.2 was this:
https://gist.github.com/SteveALee/da24c2be633340b8791066dd98eb5d0b/1e49fd6e21fa9ae98dbb3c04e6a8850b401c1c4c

@Giermann i missed that UI completely and cloned locally to search. Thanks.

ASIO got open sourced recently, so it's now possible to distribute binaries of it. The Audacity team will no doubt do that for the upcoming 4.0 and maybe the last 3.7.x release; in the meantime, I made a precompiled binary here: https://github.com/LeoWattenberg/audacity/releases/tag/asio

@LeoWattenberg said:

ASIO got open sourced recently,

Wow - really!? Not heard that. What took them so long!!! LOL. I wonder if Steinberg was influenced by Microsoft's goal of shipping it in Windows.

Thanks for the link but as always I would caution everyone to be careful with installing unverified binaries!

More info from Steinberg. The ASIO SDK is dual licensed under GPL 3 so will be compatible with Audacity. VST also open sourced under MIT, but there's an "iffy" statement on logo use. Good News

Great news! On installing Leo's binary, I am presented with 3 ASIO options....  Generic low latency ASIO driver, Realtek ASIO and Steinberg built-in ASIO driver.  Any thoughts on which to use?  I have a 4-channel Behringer interface. ==>  and thanks Steve for all your work to date! Regards Chris

@Chris-C-Bristol No idea! LOL
If that's the options in Audacity when you run it then you probably wan't the one that came with the Behringer. Maybe Generic one?
Prepare to be underwhelmed with the multi-channel support of Audacity!

The Behringer didn't come with any drivers but it's worked fine at 4 channels with your builds.  I guess the thing to do is to try them all (latency etc).  I'll report back with results. Chris

I've done a bit more experimentation.  with Audacity and my Behringer UMC 404HD (4 channel USB audio interface).  Turns out I was wrong about no Behringer driver - there is one, and it's recently been updated. I have 2 computers and they behave differently.. They both offer Audio Setup/Host/MME, Windows DirectSound, Windows WASAPI and the ASIO selection.  In both cases, it is necessary to go Audio Setup/Audio Settings/Recordings/choose the ASIO driver;  The number of channels can then be selected.  The Audio Setup/Recording Device can be selected, and then Audio Setup/Recording Channels.  Not sure whether the order of doing things is critical, but both seem to be necessary. Windows 10 laptop with i5 processor (so not capable of Windows 11) Only offers me the UMC ASIO Driver, and I can select 4 channels - i.e. behaves exactly as it did with Steve's script building 3.7.5alpha. Windows 11 machine Offers me Generic Low Latency Driver (max 2 channels), RealtekASIO (max 2 channels), Steinberg built-in ASIO Driver (1 channel only!) and the UMC ASIO Driver (4 channels).  Before I upgraded to Windows 11 it used to offer me only the UMC driver. Perhaps Windows 11 already has some ASIO drivers (Generic and Steinberg?) and the Windows 11 drivers for my Realtek audio card also have ASIO functionality??  In any case, the Behringer driver is the only one which can use the 4 channels.  The Realtek one is not surprising, since it's a stereo device, but it's a bit surprising that the Generic and Steinberg drivers are so limited. Not used it in anger yet, but it seems likely to be OK! Thanks Steve and Leo

Good grief! So much for simplicity. Best of luck.

I heard microsoft planned to provide ASIO in Windows, perhaps along with MIDI 2 support. But i dont know what or how you'd use it.

@Chris-C-Bristol
This "Steinberg built-in ASIO Driver" should be compatible with Windows 10 too, but I never tested it.
According to the help article, there should be a control panel - maybe you can find some information, why it only offers 1 channel:
https://helpcenter.steinberg.de/hc/en-us/articles/17863730844946-Steinberg-built-in-ASIO-Driver-information-download

I found the Steinberg control panel at C:\Program Files\Steinberg\Asio\asiobtinsetup.exe Eventually I managed to set it to 4 channels in the control panel and in Audacity, but it kept crashing.  Eventually stable (reasons unknown) and recording 4 channels.  However, 3 and 4 were swapped!  Using the UMC driver didn't swap 3&4, so either there is a bug in the Steinberg driver for 4 channels or the UMC driver and hardware are both wrong and compensate... I did wonder whether the Generic was just a copy of the Steinberg, but the behaviour seems different- as in it now doesn't work at all, and neither does the RealTek one  - they go into hardware scanning mode, and then complain about an invalid sample rate.. Conclusion:  The UMC driver is easiest to work with; the Steinberg driver works with some difficulty and needs some post-production channel swapping. Regards Chris

@Chris-C-Bristol good grief! Thanks for the info.