What is important with seals is that they remain elastic and in contact with the surfaces
It's important to use backer rod (this is not to save caulk - this
is because you need 2 point contact with caulk - otherwise it fails).
any acoustic caulk will work - butyl caulks work pretty well - silicone caulks work
Outside - my best recommendation would be Big-Stretch which is made by
This is some of the best caulk I have ever used - a bit pricy but it
stretches like crazy (up to 500% - and that is not just manufacturer's hype) - can span
some huge joints - and is an easy cleanup with water.
--------------------acoustic wall panels