ChangeOutputDevice.ps1

<#
.DESCRIPTION
https://www.powershellgallery.com/packages/AudioDeviceCmdlets/3.1.0.2
https://github.com/frgnca/AudioDeviceCmdlets

.PARAMETER SetDevice
If specified, the script will attempt to set the audio device environment variables.

.EXAMPLE
Get-AudioDevice -List | Where-Object Type -like "Playback" | Where-Object name -like "*Realtek*"
Set-AudioDevice -ID "{0.0.0.00000000}.{4229d439-1b7d-4deb-894e-544bb0fa40e1}" # speakers
Set-AudioDevice -ID "{0.0.0.00000000}.{69274eea-2c89-451d-813a-c9407258be99}" # headphones
Get-AudioDevice -List | Where-Object Type -like "Recording" | Where-Object Name -Like "*V8*" | Set-AudioDevice # set v8 mixer as default recording device
Get-AudioDevice -List | Where-Object Type -Like "Playback" | Where-Object Name -Like "*speakers*" | Set-AudioDevice # set speakers as default playback device

.NOTES
Requires the AudioDeviceCmdlets module
Install-Module -Name AudioDeviceCmdlets -Scope CurrentUser

Edit `$OutputDevices below to set the playback devices and their cycle order.
#>

param (
    [switch]$SetDevice
)

$OutputDevices = @("*Output Monitor*", "*Headphones*", "*Output Mixer*")

function WindowsNotificationBalloon($text) {
    # windows 10 notification balloon
    Add-Type -AssemblyName System.Windows.Forms
    $global:BalloonNotification = New-Object System.Windows.Forms.NotifyIcon

    $path = (Get-Process -id $pid).Path
    $BalloonNotification.Icon = [System.Drawing.Icon]::ExtractAssociatedIcon($path)
    $BalloonNotification.BalloonTipIcon = [System.Windows.Forms.ToolTipIcon]::Info
    $BalloonNotification.BalloonTipText = "${text}"
    $BalloonNotification.BalloonTipTitle = "Change Output Device"
    $BalloonNotification.Visible = $true
    $BalloonNotification.ShowBalloonTip(5000)
}

function checkAudioDeviceCmdlets() {
    # if AudioDeviceCmdlets module is not installed, prompt to install it
    if (!(Get-Module -ListAvailable -Name AudioDeviceCmdlets -ErrorAction SilentlyContinue)) {
        Write-Host "`nAudioDeviceCmdlets module is not installed." -ForegroundColor Red
        Write-Host "Install AudioDeviceCmdlets module ? [Y/n] " -NoNewline -ForegroundColor Yellow
        $response = Read-Host
        if ($response -eq "Y" -or $response -eq "y" -or $response -eq "") {
            Install-Module -Name AudioDeviceCmdlets -Scope CurrentUser
        } else {
            Write-Host "Exiting script."
        }
        return
    }
}


if ($SetDevice) {
    checkAudioDeviceCmdlets

    Write-Host "`nAvailable Playback Audio Devices :"
    Get-AudioDevice -List | Where-Object { $_.Type -eq "Playback" } | Select-Object Index, Default, DefaultCommunication, Name | Format-Table -AutoSize

    Write-Host "`nCurrent Value: "
    Write-Host "OutputDevices = @($($OutputDevices -join ', '))" -ForegroundColor Green
    

    Write-Host "`nRegex Pattern (Type the whole line to the prompt) : "
    Write-Host '^\$OutputDevices\s*=.*' -ForegroundColor Red
    Write-Host "`nEnter Regex Pattern to find what variable to change : " -NoNewline
    $regexPattern = Read-Host

    Write-Host "`n`n`nPossible new variable value (Type the whole line to the prompt) : "
    Write-Host '$OutputDevices = @("*Output Monitor*", "*Headphones*", "*Output Mixer*")' -ForegroundColor Red
    Write-Host "`nSet variable value : " -NoNewline
    $newValue = Read-Host
    

    if ($null -eq $regexPattern -or $regexPattern -eq "") {
        return Write-Host "`nNo regex pattern entered. Exiting script."
    }

    if ($null -eq $newValue -or $newValue -eq "") {
        return Write-Host "`nNo new value entered. Exiting script."
    }

    $scriptsDir = Split-Path -Parent $MyInvocation.MyCommand.Definition
    Set-Location -Path $scriptsDir
    $scriptPath = "$(Get-Location)\ChangeOutputDevice.ps1"

    $content = Get-Content -Path $scriptPath

    # The regex '^\$TargetVar\s*=.*' finds the line starting with $TargetVar = [anything]
    $modifiedContent = $content -replace $regexPattern, $newValue

    Set-Content -Path $scriptPath -Value $modifiedContent

    return
}

#!########################################################################################################
#!                                        Check and Change Output Device                                 #
#!########################################################################################################

checkAudioDeviceCmdlets

$playbackDevices = @(Get-AudioDevice -List | Where-Object { $_.Type -eq "Playback" })
$availableOutputDevices = @(
    foreach ($devicePattern in $OutputDevices) {
        $playbackDevices | Where-Object { $_.Name -like $devicePattern } | Select-Object -First 1
    }
)

if ($availableOutputDevices.Count -eq 0) {
    Write-Host "No configured output devices are currently available." -ForegroundColor Yellow
    return
}

$currentDevice = Get-AudioDevice -PlaybackCommunication
$currentIndex = -1
for ($index = 0; $index -lt $availableOutputDevices.Count; $index++) {
    if ($availableOutputDevices[$index].ID -eq $currentDevice.ID) {
        $currentIndex = $index
        break
    }
}

# An unconfigured current device starts the cycle at its first available entry.
$nextIndex = if ($currentIndex -lt 0) { 0 } else { ($currentIndex + 1) % $availableOutputDevices.Count }
$nextDevice = $availableOutputDevices[$nextIndex]

Write-Host "Change default audio device to $($nextDevice.Name)."
$nextDevice | Set-AudioDevice
WindowsNotificationBalloon "Change default audio device to $($nextDevice.Name)."