What does 'Fast mean?

What reading glasses can do to make things clear.As we get old we get "used" to the way things are.Reading glasses clear things up again "quickly"...giving us that wow!!!. Getting used to a sound "your sound" then all of the sudden there is a change ,....because change was made.If it was a good change,for the better ,it probably cleared things up a bit....WOW.So it sounds fast again.

Glider, the reason for my final sentence is because I believe some audio gear overemphasises attack to make demos more exciting and sell more. More accurate does not necessarily mean more attack.

There is also definitely some gear that lessens attack and softens everything .... some will prefer this presentation.

I've always thought of "fast" as referring to the back end of the waveform. It doesn't have any overhang or ringing. The initial transient is handled pretty well by most components, but only a few components can stop as quickly as they start. In electronics it's probably a factor of the power supply and with speakers the crossover and mass of the driver. If a component distorts the leading transient signal it can make for a faster overall presentation, but will lead to long term fatigue.

Language is always a little misleading when describing what we hear.

In the tube world fast would be Telefunken 806S, 803s, GEC CV4085

Chopping off the overhang can be unnatural reproduction of music. A balance is needed for accuracy - the world is not all black and white. Arthur