STYLE & TECHNIQUE
When I sing, I use exactly the same vocal techniques if I’m singing classical music and opera, as when I’m singing rock, jazz, folk etc. The difference is not, in fact, in the technique at all, but in the style of voice I’m using.
When I sing classical music and opera, I use what I call my formal, classical voice (so I sound like an opera singer). When I sing contemporary styles of music, I use my natural voice (so I sound more like a jazz, rock or pop singer). The issue is not with technique, but with the ability to sing in different styles – and in my experience, it is something that not a lot of singers can do. In fact, in the “journey” that is involved in training somebody’s voice, I find that most people can only really sing either classical or contemporary styles of music. This is why you sometimes hear opera singers attempting to sing, for example, Beatles’ songs, but in an operatic voice (and I for one, think that sounds pretty awful!). By the same token, listening to Chris Martin from Coldplay attempting to sing an aria from an opera in his natural voice is going to sound pretty weird (although of course he hasn't got a trained voice anyway, which you'd need to sing classical music and opera properly).
So the ability to hear and then be able to replicate different styles of music is key to being able to sing them – but, and it’s a big but, it’s also not really a two way street. If you’ve had a classical training and you can easily switch to singing in your natural voice, then great. It’s unlikely that you’ll be able to sing in a classical voice without training, as I've said above (although there are some lucky individuals who can just do this – but they’re an exception).
When I was doing my classical training years ago, I was determined to be able to continue singing contemporary styles of music, but I have to admit that for about six months, once my training was under way, I found it hard to switch from classical to contemporary styles, with the result that both sounded a bit odd! I persevered, however, and managed eventually to be able to just switch instantly from one style to the other – it’s something that’s helped me not just with my own singing, but it's enabled me to be able to teach all styles of music; to give a full classical operatic training, as well as to help people with auditioning for the X Factor or whatever floats their boat!
So learning about and understanding your own voice is important, as is being honest with yourself about your natural ability before you start lessons. I remember being asked by one potential student how long it would take to sound like Leona Lewis (to be fair, she was a teenager!). Obviously, whether anybody ends up sounding like Leona Lewis or not is determined first and foremost by the amount of natural talent they start with (eg. I’d never have made an astronomer because I have no science brain cells and am not good at maths!). It’s also, of course, determined by the type of voice you have (as mentioned in more detail in one of my previous posts). If you’re a Dramatic or Low Contralto, then no, you’re never going to sound like Leona Lewis who is either a Lyric Coloratura Soprano or a Dramatic Coloratura Soprano (I have rarely listened to her, so I’m not sure!).
Bottom line: you’re better off learning classical singing techniques, which are safe and won't damage your voice and finding a teacher who can do this but who also teaches contemporary styles of singing, if that’s what you want to sing. Finally you need to practise - as whatever natural talent you have got, it will improve with structured practice. If your lessons aren’t challenging you, get another teacher!