Dear @frogman : I think I know you on MUSIC/audio reproduction targets and of course rhythm is at the top chatacteristic and is not for free or at random because exist several reasons behind it.
From where comes/came that live MUSIC rhythm?. Well and this is only my take about:
months ago maybe years in other Agon forum was opened a thread with a dialogue about rhythm and I participated down there and what I posted is that differences for the better or bad belongs to Transient Response here is where starts MUSIC and from that Transient Response ( instruments/audio system ) is developed the Rhythm and MUSIC Dynamics.
That first attack that @bdp24 is exactly where start Transient Response but the Rhythm that is developed depends of several issues:
first which the rhythm proposed by the MUSIC composer and is very important because ( example ) the Orchestra Director needs a correct explicit interpretation of what the composer try to achieve and the Director must has to transmit that issue to the Orchestra players that's why so many training sessions to show a MUSICAL score to the Hall public seated there.
But here exist some troubles: one is the venue that has implicated part of the natural color of tha MUSIC score, then the quality level of all the player instruments and obviously their talent invloved there but each human being today can have a rhtyhm/feels and 6 hours latter a little different one due to changes in the mood or for whatever other reason.
With out transient response rhythm can exist, overall is to complicated to explain it and needs a new thread but at the end that rhythm is what makes the differences between cartridges even coming from the same manufacturer.
The ones like me that owns or listened in their system several cartridges know exactly what I'm talking about. Each cartridge has its own rhythm that sometime makes us to move our legs/foots very easy and other times not so easy or even no movements at all and yes we all have our own rhythm too.
Cartridges with out rhythm are cartridges with bad transient response or not so good levels.
R.