Alice in Chains — An Introduction (grandaha.com)
Alice in Chains' unique vocal blend is built on a specific harmony method that has fooled many fans into assuming it's just one singer.
That signature Alice in Chains sound? It's not one voice — it's Layne Staley and Jerry Cantrell singing in tight harmony, often nearly in unison, so seamlessly that people swear it's a single throat. The blend is the whole point.