Feedback/Balancing advice for a spell my character is possibly researching

[Tiamatwing]

Creating a custom spell for my enchanter wizard to research and wanted some feedback on what I've come up with, DM already ok with current version but thought i'd get a wider range of opinions for fine tuning.
Basically Tasha's hideous laughter is one of the go to spells for her and always wanting to target more people than the current max, so asked if it was possible to create an improved version of the spell with the rough final draft having the range/effect of THL but affects all targets in a 15ft cube and the spell (current name is Kallista's cackling chorus) itself being a 4th level in power.

[tKUUNK]

sounds pretty good. nice name.

You could probably increase the range to 60'. at least.

why 4th level and not 3rd? seems on par with Hallucinatory Pattern. interested to see what others think re: spell level.

[NecessaryWeevil]

Charm immunity protects from Hypnotic Pattern but not from this spell, however.

[JackPhoenix]

Charm immunity protects from Hypnotic Pattern but not from this spell, however.

Hypnotic Pattern, however, doesn't offer a save every turn, and doesn't have Int limit on what can be affected.

[NecessaryWeevil]

True. 3rd level could be reasonable then.

[Man_Over_Game]

Hypnotic Pattern also doesn't knock the creatures prone, either.

You could probably make it a 20ft cube as a 4th level spell. This has the added benefit of being a different niche than Hypnotic Pattern. Not explicitly better or worse, just different enough to justify having both.