Tracey Macleod: A reluctant diva finds her voice

I secretly believe I'm quite a good singer. But so, presumably, do most of the deluded people who turn up to audition for The X Factor. Singing along to the radio, my voice sounds decent, even pleasing, at least to me. I can muster a basic harmony line; James Taylor and I have been duetting together for decades, on a strictly in-car basis.

But in public, something goes wrong. Exposed to strange ears, my thrilling contralto is replaced by a thin, nasal sound. At karaoke nights, I usually take refuge behind "Reet Petite" or The Proclaimers' "500 Miles", songs which depend largely on the ability to make funny noises. The idea of singing a straight song, in that weedy, reedy voice, is horrific to me. So my secret fantasy is to learn to sing. Or at least to have the confidence to sing in public. I want to release my inner show-off, maybe even to make music with other people. To sing a karaoke song that doesn't rely on yodelling for effect.

My singing teacher, Bridget de Courcy, is recommended by a friend who discovered after one session that far from being tone deaf, she had a beautiful, silvery soprano voice. Bridget has worked a lot with actors and, over the phone, she sounds fabulously theatrical. "I'm interested in whatever you bring me, and what we find together," she tells me. "It's like an animal that comes roaring out."

Cut to me and my caged animal standing nervously at the piano in Bridget's north-London front room, while she questions me about my singing history. I tell her I think my voice is OK, but I'm not sure where my range lies, or what style of music would suit me best. My mission, I tell her, is to be able to find My Song at karaoke. I'm sure I see a flicker of pain pass across her features.

The first two minutes are the most excruciating. Singing into the face of a complete stranger is something I last did at school, either for my Grade IV piano exam (failed) or my audition for the choir (still waiting to hear back). Bridget goes up and down the piano scale note by note, and I follow, singing "ma-ma-ma".

When the roar of blood in my ears subsides, I'm encouraged to hear that I appear to be in tune ("perfectly, perfectly in tune," according to the relentlessly encouraging Bridget). I can also hear that my voice sounds fuller in the lower register, switching at some point on the way up into a more strangulated, higher voice. "We're going to correct that right now!" promises Bridget.

What follows over the next hour is an idiosyncratic mix of image-making and technical information about how the voice works. I'm encouraged to think about singing from the back of my head, rather than my throat; to imagine there's a little man in a rowing boat pulling the notes out of me with each stroke; and – the horror – to sing as though I'm a child calling for its mother. Ma-ma-ma... Oh God, am I actually going to start crying for my mother?

But Bridget's suggestions work. By relaxing my face, or changing the vowel sound, I can feel that I'm using a different part of my voice. The strangulated higher voice – what Bridget refers to as a "yapping terrier" – gives way to a richer, fuller sound, and the high notes come more easily. Bridget is effusive, punctuating my "ma-ma-mas" with "just right!" and "lovely sound!" until I start feeling like Maria Callas.

Just when I've got comfy with the "ma-ma-mas", we move on to "a-ma-ri-li" and – what fresh hell is this? – "yam-burr-aaaa". Bridget encourages me to sing with a relaxed smile in my voice, and a manic rictus on my face. I'm only grateful that The Independent website isn't running this as a video report.

But the amused face produces amazing results. I'm going up much higher than I thought I could, and it sounds good. "What a lovely soouuuuund! That's pure as a bell!" Bridget trills excitably. "What colour would you say that voice was?" Um, orange? I venture, my eye resting on a nearby wall. Bridget seems delighted. "Orange! Orange has energy, lightness, drama. That combination of colours is your tone. It has a freshness, an innocence, a fullness. A woman's sound..."

This is better than therapy. And at £35 a session, a lot cheaper. Towards the end of our time, buoyed by a new confidence, I suggest we tackle a song. I'm hoping, I suppose, that Bridget will choose something by Burt Bacharach, or Nina Simone – something that will let me use my new voice in a karaoke-friendly context. Instead, she pulls out a traditional folk song called "The Mallow Fling". As I learn it, line by line, imitating Bridget's crystalline diction and pure soprano, I have a sinking feeling that whatever this new voice is, it isn't going to come roaring out at a karaoke night any time soon.

Bridget confirms my hunch. "I don't think you'll really find anything in karaoke – it all tends to be a bit pop," she tells me. Hmmm, so like my friend who unlocked a beautiful soprano, my inner beast is an exotic, endangered species, too rarefied to be exposed in public.

When I play the tape at home, my partner is less than supportive. "Why are you singing in that posh voice?" he hoots. "Did you go for elocution lessons as well as singing lessons? You sound like a distressed Joyce Grenfell."

Let him scoff. I prefer to trust the judgement of Bridget, the professional, who called my voice "indisputably lovely" and said it would be a shame if I didn't do anything with it. Until they start using "The Mallow Fling" in karaoke clubs, it may be that I never will. But for that one brief hour in Muswell Hill, I was golden.

See bridgetdecourcy.co.uk