1" foam/treatment will work to some degree, in particular with higher frequencies as noted, just not as much as equivalent 2" foam product.
No way to know what will "sound best" without trying.
I like the "lego" approach with wall treatments. Start with smaller measured amounts of treatment, like 2'X2'X1". Add more or less as needed until best results achieved at primary listening location(s).
No way to know what will "sound best" without trying.
I like the "lego" approach with wall treatments. Start with smaller measured amounts of treatment, like 2'X2'X1". Add more or less as needed until best results achieved at primary listening location(s).