Does you car or motorbike sound dull or loud? Use a Helmholtz resonator in the exhaust. As simple as adding a pipe to the exhaust:

dirtydeedsindustries.com/product/helmholtz-resonator/

or buying an expensive, sound engineered addon:

by www.hotrod.com/articles/add-a-proper-exhaust-note-to-your-v-6-powered-fifth-gen-camaro/ and similar products by  www.saclam.com/products/products.html or www.genracer.com/ark-grip-collection-cat-back-hyundai-genesis-coupe-3-8-10/

The whole instrument as a diagram. All of the blue parts influence the sound of the engine and car manufacturers take great pride in making their product sound «on brand».

 

And finally something totally uber-useless:

«The electronics also allow a spot of fuel into the exhaust when you short-shift up the gearbox which gives a pleasing reverb as you change.»
www.telegraph.co.uk Audi-RS5-review

I’m totally against the use of cars. They are not friendly to our earth and a liter of petrol should cost at least 10 €. I love the emotions that cars evoke!