Sir – I read with some interest the review of the Lexus car in last week’s issue. As a sound engineer, I am not really into the market for high performance cars, but my eye was caught by a reference to an ‘837W’ audio system.

If we allow for the inevitable inefficiencies in any amplifier, this implies that the unit will consume about 900W at maximum power, which a little arithmetic will show necessitates drawing some 75 amps from the car’s electrical system.

In addition, since I can fill Oxford Town Hall to unpleasant levels with a 200W amplifier, it seems unlikely that the occupants would ever subject themselves to over 800W in the tiny confines of a car, even if the loudspeakers were incredibly inefficient.

I doubt if a correctly conducted measurement (continuous sinewave, measured with an RMS wattmeter) would show anything approaching 837W, so why are car manufacturers allowed to get away with such claims? On the same basis, they could claim that the undoubtedly fast Lexus RC F could achieve 837mph.

Richard Simmons
Oxon