Can you 'make' the D5/D6 quieter at low revs?

[Ulrikas PA]

Not sure what I'm asking here, but here goes:-

I've a 2017MY V60 Twin Engine Diesel which runs on the battery until it's empty, when the engine clatters into life - normally stone cold at 30 or 40mph, so not in top gear.

I've owned or run lots of diesels (maybe 30 of them), and it reminds me of an old VW PD engine aurally until you either get into top gear or get higher up the rev range if overtaking etc, when it sounds fine.

I add some Miller's diesel max stuff every other tank, but I'm assuming the sound is just the way it is with the 5 cylinder diesel?

[5cilinder]

What im suspecting is that they have advanced the injection for economics...which results in more peak pressure hence noise.

Those working vans also have loud clattering diesels with relative large displacements and low horse power for durabillity and injection advanced for economics.

That millers diesel max stuff is pretty good btw