Uses SMO to determine the path that new databases will be created in

Get-SqlServerDefaultDataPath.ps1

Enter file contents hereparam(
  [Parameter(Mandatory=$true)] [string]$sqlServer
)

[reflection.assembly]::LoadWithPartialName("Microsoft.SqlServer.Smo") > $null
$smoServer = new-object Microsoft.SqlServer.Management.Smo.Server $sqlServer

$str = $smoServer.DefaultFile # or .DefaultLog for tlog files
if ($str)
{
    # if DefaultFile property is present, an explicit default has been configured
    $str;
}else{
    # if DefaultFile property is empty, it means default path has not been changed
    # and should be taken from where the MasterDB sits
    $smoServer.MasterDBPath; # or .MasterDBLogPath for tlog
}