Matching mp3 in folder to a txt

$files = (Get-Childitem *.mp3).Name
$list =
foreach ($i in (Get-Content list.txt))
{
    $i.Trim() -replace '^\d+\.(.+)\sh...s?:.+(\.mp3)$','$1$2' -replace ' ', ''
}

foreach ($diff in (Compare-Object $files $list))
{
    if ($diff.SideIndicator -eq '<=') { 'Not in list.txt: ' + $diff.InputObject }
    if ($diff.SideIndicator -eq '=>') { 'Not in folder: ' + $diff.InputObject }
}