Chris Cornell cemented his reputation long ago as one of the greatest rock vocalists ever, first with Soundgarden in the 1980s and ’90s (and currently), and then with Audioslave in the early 2000s. But Cornell, who is now 50 years old, has a rather intriguing history of crossing genres, beginning with “Temple of the Dog” (1991), which was certainly rock, yet with hints of gospel and folk. His surprising 1997 version of “Ave Maria” (on “A Very Special Christmas 3”) indicated an interest in music far outside the usual grunge/metal arena. And with his 1998 song “Sunshower” (on the “Great Expectations” soundtrack), which became a hit without ever being released as a single, and “Euphoria Morning” (1999), his first solo album, Cornell further demonstrated his ability to sing (and write) within numerous genres. His 2009 album, “Scream,” caused plenty of screams—from fans who welcomed the electro-R&B-Timbaland-produced songs and from those who hated it and saw it as a sign of the apocalypse.

In recent years, Cornell has written and performed a hit song for a blockbuster movie (“You Know My Name”, the theme song for the 2006 James Bond film, Casino Royale), sang lead on the funky, Euro-fusion tune “Lies” with Gabin, and crooned a mellow, old-school duet (“All I Have To Do Is Dream”) with Rita Wilson on Mrs. Tom Hanks’s 2012 solo album, “AM/FM.” And in his various solo acoustic tours [see my October 2013 review of one such show], Cornell has always played some left field tunes, such as Michael Jackson’s “Billy Jean,” which he first played unplugged many years ago as a slow-burning blues song (and inspiring a similar take from “American Idol” winner David Cook in 2008).

There are more examples, but that’s enough of an intro to Cornell’s latest collaboration, which was released last week: the single, “Heavy Is the Head,” with the Zac Brown Band, which appears on ZBB’s forthcoming album, “Jekyll + Hyde”. I’ve enjoyed the ZBB’s past albums, which are a mixture of Souther-country-rock, traditional country, and some Jimmy Buffet-type tunes, and I expected I would enjoy the tune. In fact, I think it is a great cut; it is far heavier than expected and is a near perfect marriage of Southern/country rock and grunge, hence my use of the word “Southerngarden”. The song is built on a distorted, grungy bass line, which leads into some distorted guitar and Cornell’s somewhat menacing vocals; it builds over some fine riffs and, at the 3-minute mark, a nifty Soundgarden-ish breakdown and some trademark wailing. Here is a recent performance for SNL, marred only by a bad mix (the vocals are pushed too the back):