I have never heard the KH 420. I can only speak for KH 310 + KH 750 which I own.
Distortion specs on the KH 750 are not as good as on the O800 (which i used with O300 monitors in the past).
That made me hesitate at first, but the KH 750 sounds very good. Tight dry bass like you would expect when you are familiar with O800 / KH 805 / KH 810. At high SPL differences may start to become apparent but even then it sounds very clean to me. I do like that the sub is closed as it provides better performance in the time domain. The O800 was ported design, but I must admit it sounded very good (tight and dry) as well..
Yesterday evening I realigned the KH 750 sub (with KH 310 monitors) using the Neumann MA 1 (see attached screenshots).
I am very satisfied with the result. I hear more information, especially in the low-end.
In addition to the frequency response the KH 750 provides phase response compensation.
Martijn
Distortion specs on the KH 750 are not as good as on the O800 (which i used with O300 monitors in the past).
That made me hesitate at first, but the KH 750 sounds very good. Tight dry bass like you would expect when you are familiar with O800 / KH 805 / KH 810. At high SPL differences may start to become apparent but even then it sounds very clean to me. I do like that the sub is closed as it provides better performance in the time domain. The O800 was ported design, but I must admit it sounded very good (tight and dry) as well..
Yesterday evening I realigned the KH 750 sub (with KH 310 monitors) using the Neumann MA 1 (see attached screenshots).
I am very satisfied with the result. I hear more information, especially in the low-end.
In addition to the frequency response the KH 750 provides phase response compensation.
Martijn