Tight bass relates to timing.
When a Bass note is exercised if it reverberates or cant musically keep up with the song its timing is off and it's called not tight...
You could add "tunefull" and you bring in timbre and definition as well.
What is Tight Bass?
I’m confused. Speaker size with a large woofer…can it be tight?
is it about efficiency? Amp power? Electrostatic?