Will seem again a super simple question for you - not for me tho!
Not really, I actually realized that the $rgb() function alters the sort order, as if there was a number in front of the artist name, therefore, all the names in red are sorted after those beginning with a special characters and before those beginning with a number. I never noticed something similar before and I actually don't know how to handle it. Does that happen to you, too?
Anyway, sort order issue aside, to compare the whole field with specific values I would use the $strstr() function rather than $strcmp(), for example: $ifequal($strstr(%artist%,Bach),1,$rgb(255,0,0),
$ifequal($strstr(%artist%,Chopin),1,$rgb(255,0,0),
$ifequal($strstr(%artist%,Velvet Underground),1,$rgb(255,0,0),
)))%artist%
The above is just to get the idea, but to make it work properly in real life you need to manage capital letters and prefixes, like this:
$puts(ar,$stripprefix($lower(%artist%)))
$ifequal($strstr($get(ar),bach),1,$rgb(255,0,0),
$ifequal($strstr($get(ar),chopin),1,$rgb(255,0,0),
$ifequal($strstr($get(ar),velvet underground),1,$rgb(255,0,0),
)))$swapprefix(%artist%)