I’ve just got back from a very interesting trip to Slovenia (that’s the very northern-most tip of the old Yugoslavia, bordering Italy and Austria) to try BMW’s all-new flagship four-cylinder engine.

Despite the performance credentials of this twin-turbo unit, it was bolted into the nose of an X1.

 However, picture-postcard snowy conditions in the stunning countryside outside the capital Ljubljana meant the X1’s all-wheel drive and winter tyres were very welcome.

The new ‘28’ engine, the most powerful four-cylinder BMW engine for the time being, is unobtrusively efficient. It pulls well from as little as 1250rpm and has more overtaking ability than its part-throttle ordinariness might suggest to the driver.

And that’s the problem. As impressively as it, the humdrum soundtrack really spoils the party. Unsurprisingly, it lacks the sense of slickness and inherent smoothness of the twin-turbo straight-six in the X3 and X6 that I also tried in Slovenia. But I couldn’t help wondering just how much of the sensation of the classic in-line six comes from the soundtrack.

There’s a very powerful move across the industry towards four-cylinder engines as Co2 regulations force car makers to downsize engines in EU markets. So maybe it’s also time to start introducing both active noise cancellation and artificial, in-cabin, noise generation so we don’t lose that crucial sonic experience.

Last year I sat in the back of a bass-bin equipped Mini Clubman prototype, and with the flick of switch the engine was given an artificial V8 rumble, made all the more realistic by the bass throb delivered through the floor by the sub-woofer. It’s an amazingly effective technique, even if it is fake.

I was also prepared to come away from this launch declaring the ‘death of the straight-six’. Not a chance. Last year BMW’s output was 56 per cent petrol-powered and 44 per cent diesel. Dividing up the petrol-powered production figures, just 27 per cent (or 272,000) BMW models had four cylinder engines and nine per cent had eight-cylinder engines.

A massive 64 per cent (or 502,000) of models had the classic six-pot engine. And you can probably add another 150,000+ straight-six diesels.

Of course, BMW doesn’t sell four cylinder engines in the US and booming markets such as Russia and China aren’t hobbled by fuel economy regulations. So the straight-six will prosper for a long time to come in much of the rest of the world.