Italian car manufacturer Alfa Romeo claims to have found the best-sounding tunnels in the UK, with a helping hand from the Stelvio Quadrifoglio performance SUV. The company joined forces with one of the UK’s leading acoustic consultancies, Sandy Brown, to create its ‘Sound Tunnel Index’.

To gather data, Alfa Romeo began by asking its ‘Alfisti’ fanbase to nominate the UK tunnels that provide the best acoustics. The top 10 were shared with Sandy Brown, whose experts visited each tunnel armed with sound-measuring equipment and the 503 bhp, V6-engined Stelvio Quadrifoglio.

With the passenger window wound down and the car in Dynamic mode to make the most of its exhaust note, Sandy Brown drove the car through each tunnel, measuring the engine and exhaust sound, plus tyre, road and wind noise. The results were then used alongside the drivers’ favourites to find Britain’s best tunnel.

Alfa Romeo Stelvio Quadrifoglio UK's best-sounding tunnels.

The winner was the Penmaenbach tunnel in North Wales, which benefitted from its twin-bore design that creates one-way traffic in each bore. Sandy Brown also praised the tunnel for its “excellent road surface” and “distinctive U-shaped profile”, which helped it achieve top spot.

That said, the Saltash tunnel in Cornwall was ranked above Penmaenbach by the scientists, but a fourth-place ranking from the Alfisti saw it slip behind the more highly rated Welsh tunnel. The rest of the top four included the Beaminster tunnel in Dorset and the Hindhead tunnel in Surrey.

The Holmesdale tunnel in Enfield and the two-kilometre Queensway tunnel that links Cheshire and Liverpool shared fifth place, despite the latter taking second spot in the subjective ranking. Further down the order were the Tyne tunnel on the A19 near Newcastle and the Dartford tunnel in Kent.

Alfa Romeo Stelvio Quadrifoglio UK's best-sounding tunnels.

Richard King, an associate at Sandy Brown, suggested car enthusiasts could use the findings to help increase their enjoyment of road trips and their vehicles.

“The shape and size of tunnels, their length, the speed of the road, background sounds such as other cars, airflow and tyre noise, all have an impact on the sound you hear while driving through it,” he said. “This is heightened in a performance SUV such as the Stelvio Quadrifoglio, where the combination of the V6 Bi-Turbo engine and exhaust sound add to the excitement, so this index will help petrolheads and car lovers across the UK make the most of their drives.”

Gallery: Alfa Romeo uses science to find the UK's best-sounding tunnels