How far do you push the keys until you can hear sound?

[boku77u]

Hello,

Something seems out of sync with my SV-1. Can someone please let me know how far you have to push the keys until you can hear sound? I know it is weighted keys, but it feels like it registers too late.

That is, sometimes it feels all good and it's easy to play. Other times it feels heavy, as if the tone comes in too late and I can't play it flowingly.