Originally Posted by
Dr.db
Thanks for the link to wiki and the TAD-shematic!
We will use an active crossover for this project to get started. Probably weŽll stay with this, as I have very limited skills in passive crossovers.
Using the TAD crossover with our JBL components probably isnŽt working at all, so we`ll better stick with an active xover.
Ian, what I had discovered before asking is that phaseshift caused by a filter changes over the frequency-range. This made me wonder, if the attempt of an electronic offset (crossover) has the same effect as a physical offset regarding the time-alignment. Reading your link, the pictures do say so.
IŽm aware of my lacking knowledge, so IŽll try to avoid going into detail any further.
Just let me ask this simplified: if a compression driver is located significantly behind the woofer because of a deep horn, is a higher crossover-slope on the woofers lowpass a smart idea in most cases?
Did JBL use a 24db lowpass (woofer) and 12db highpass (midhorn) on the DD66000 for the same reason of time-alignment? Or is this because the acoustical roll-off of the midhorn(~12db) sums with the electrical roll-off (12db) a 24db slope and therefor the lowpass needs 24db slope as well to match up?