For those of us who enjoy the epic and empowering feeling some metal genres and bands bring to the table, the chorus, along with the intro, can be the most important part of the song. There are choruses that are so catchy they helplessly stay in your head for days, others are so unique you feel special when you listen to them, and many simply rock. Regardless of what the reason, the chorus, in the world of melodic metal at least, is what makes of breaks a song for the fans in my opinion.
Being a musician I often find myself in the conundrum that is structuring, or to sound less superficial, creating a good chorus. After many years of listening to melodic metal and none of musical training I have come to understand how to separate high quality ones from the failures. There are numerous factors which define whether or not the chorus will be successful, and among them is, of course, the fact of whether or not it connects with you, whether or not it touches you personally; something that no matter how hard a band tries, it is impossible to know beforehand for the most part. But, in my view, there are three elements that, if handled well, can aid a band to obtain a positive result at the end of the day.
First and foremost, the chords that are being played during the duration of the chorus are crucial because they not only help the singer reach better notes, but it also allows for more creativity on the vocals, and even the keyboards, bass and drums. The riffs should be in the borderline of simple and creative, of edgy and melodic; like, for example, the chords played in Jag Panzer's "Take to the Sky" are imaginative and fierce enough to allow the drummer to pound with force and speed, conveying a feeling of power, and plain and melodic enough to let lead singer Harry Conklin soar to high notes with his voice, creating a lethal combination called epic chorus. The same can be said about some of my favorites, such as "Run to the Hills" and "Aces High" (Iron Maiden), "Sky's Burning" and "Eternal Flame" (Mystic Prophecy), "Inferno(Unleash the Fire)" (Symphony X), "Endless Sacrifice" (Dream Theater), "Heart of Steel" (Manowar), "Lady of Winter" (Crimson Glory), "Bright Eyes" (Blind Guardian), "Watching Over Me" (Iced Earth), and I'll venture to say even "Master of Puppets" (Metallica). Even though all of the aforementioned belong to different epochs and styles, they still knew the formula to build a memorable chorus.
Secondly, and derivative from my first point, whats being played behind the chords in the chorus can have a huge impact in the value of it. The employment of harmonies with the guitar, melody lines or symphonic backgrounds with the keyboard, and ingenious bass lines can take the chorus to a superior level. Surprisingly enough, Doom and Black metal acts seem more incline to do so than Power metal groups. The use of violins, flutes or full orchestral fills throughout a chorus can give us an almost ethereal sensation, which, accompanied by heaviness and power, can make a remarkable chorus. Iced Earth has utilized the guitar harmonies in their choruses but usually towards the end of the song, to finish on a high; though I think they should be used more in the middle of the track, rather than when it is fading away. Iron Maiden is the prime example of how solid bass lines, although hiding in the back, can really make a difference in the chorus.
Finally, the most significant part of the chorus is the vocals. A good voice carries a chorus like a magic piece of music that can rip your brains and elevate your soul altogether. Most famous and respected singers in the world of metal are appreciated for the talent, and often gift, they posses in their voice, and there's no other place to better showcase your vocal range and originality than in an uplifting and surging chorus. The thing that separates the true awesome singers from the fine crowd is their ability to make the chorus unique. Little details such as going through a couple of different notes on the scale can have a big impact. For example, in "Run to the Hills" Bruce Dickinson goes down the scale on the second line of the chorus; if one was to omit this particularity the lines wouldn't sound as good as they originally do. The same can be said for the third line in Jag Panzer's "Take to the Sky." Other vocalists prefer to go higher on the scale towards the end of the chorus, also to good effect. Female background vocals like the ones found in "Her Ghost in the Fog" (Cradle of Filth) and "The Hunter" (Iced Earth) are smart touches that, when added, can make your chorus appealing even to those who don't enjoy the genre or band.
Other arguments can be made about how what's played before and after the chorus is also paramount, or how the lyrics are also influential. Although I agree, when it comes down to it, to the simple fan who wants something he/she can sing along with or pound his/her fist at, the melodic chorus is the essential moment, and, curiously enough, it can be so infectious that you might find yourself hiding from your friends who criticize the band to listen to it; if so, then the chorus has served its purpose.