Great clip zooma - but you should understand that my unit 'synthesizes' engine sounds and doesn't play recordings of the real thing and that this hardware is quite unsuited to making anything but the chuffing type of sound in 'steam' mode. Sorry!
Again, as you've experimented with MK2 Combo units you will have seen that engine authenticity is similarly limited in the synthesized 'petrol' and 'diesel' sounds - but, unlike the 'steam' you clearly found these acceptable for your purposes. Think of it this way - in much the same way that a cartoon of the Prime Minister is recognisable as the Prime Minister, it is not as realistic as a photograph of the Prime Minister. However, one needs to pay considerably more to get 'real' sound, To be thoroughly pedantic I would suggest that even these units, whilst a huge improvement, aren't realistic. They work by looping a fixed audio sample of the engine at a throttle dependent playback speed - with the result that as the speed of the sound changes, so does the pitch - UK readers of a certain age will know what I mean if I dub it the Pinky & Perky effect. Over a narrow rev range some engine sounds are fairly amenable to this technique whereas many others can sound ridiculous. If you check out my website you will see I've been experimenting with such systems so I'm speaking from practical experience rather than expressing an opinion.
And what about the change of timbre and/or volume when an engine is put under load during acceleration? And what about . . . . . . . . where do we stop?
My message is that we need to find a compromise where our pockets and our expectations meet.