Lexus claims the LS has one of the quietest cabins in a production car, through the use of double-glazed side windows, active noise cancellation from the car’s audio speakers and even noise-suppressing alloy wheels (which have small resonance chambers to break up waves of air pressure that would otherwise turn into road roar).
However, our decibel meter measured 65dB of ambient noise at a 70mph cruise – which is certainly quieter than the average large passenger car but a shade noisier than both the Mercedes S350 Bluetec we tested in 2013 and the BMW 730Ld in 2015. In subjective terms, the LS’s cabin seems well isolated enough – more so from wind noise than tyre roar – but it doesn’t seem like an outstandingly quiet car. But then an effective luxury car is built on more than refinement alone.
So, how’s the LS’s driveability? From a petrol-electric powertrain combining a V6 engine with 251lb ft of torque and an electric motor with 221lb ft, you might expect a responsive, waftable feel – but you don’t really get it. Those power sources combine to make the LS overcome its 2.4-tonne kerb weight (as tested) and hit 60mph from rest in a shade under six seconds when you absolutely floor the right-hand pedal. But the powertrain’s slight laziness, its hesitancy to respond to part-throttle inputs and its refusal to pick up speed in effortless fashion all make it feel ill-suited to a luxury application.
The electric motor seems to be able to supply a decent hit of torque at urban speeds, but if you want a healthy swell of acceleration at A-road or motorway speeds, the only way the hybrid system can provide it is by letting the combustion engine spin in a way that isn’t becoming of a limousine. It isn’t that the engine is particularly noisy or uncouth; it’s just that you can’t miss the presence of a V6 turning persistently at 6000rpm in an otherwise quiet luxury saloon.