Moving air

My ears are not what they used to be.  I remember going fishing with my Dad one evening and remarking: "Listen to those bats".  His response: "You can hear the bats?".    I could, but no more.  This leads me to the conclusion that my hi-fi needs no improvement on its current set-up, which will doubtless save me considerable sums of money.

However....

Good loudspeakers are difficult to design and build.  Their purpose is to move air, and yet for the best sound reproduction, you don't want the speaker cones to move.  As an example, imagine that a speaker cone is flapping back and forth generating a bass note.  Now mix in a higher frequency.  The back-and-forth movements of the cone will create a Doppler effect, blurring the pitch accuracy of the higher note.   This dual requirement to move and not move is one of the many things that make design difficult.

The science of speaker design has improved greatly during my lifetime: the little battery-powered Bluetooth things you can get are astounding for their size and price.  But still, if you want to buy a pair of speakers that gives a realistic concert-listening experience, you have to spend upwards of £15,000, and the same order of magnitude for amplifiers to drive them.

On the other hand, if you are using headphones, the price is much lower.  You can get a pair of headphones that represent the state of the art, plus a matching amp to drive them, for less than, say,£4,000 all in.   Of course they don't give the same effect as free-standing speakers, especially since deep bass notes are felt as much as heard.  None the less, the "user experience" is very satisfactory.  The main reason for the lower price is that they don't have to move as much air as free-standing speakers, so they can be made much more precise.

Going on to moving the minimum amount of air possible, you can buy ear buds.  About twenty years ago I bought a top-of-the-range pair that cost me a couple of hundred quid, that served me very well until the left transducer packed up.   But recently I came across a rave review of a pair of earbuds that you can get for under 12 quid - Ollivan KZ-ATE.  I bought a pair, mostly out of curiosity. They're astonishingly good.