This is my first time designing a passive crossover, and I'd appreciate your advice on it. I'm designing a 2-way bookshelf speaker with a 6.5" pro audio mid-woofer and a compression driver + horn combo.
The on-axis in-room measured response of the CD+horn is below (1/12 octave smoothing):
I used a first order crossover @ 8000 Hz for the CD to get a relatively flat frequency response so that I can get away with a single notch filter centered at 1000 Hz with Q value of 1. There's also an L-pad to reduce the CD level. The crossover for the woofer is a simple second-order at 1100 Hz. The actual acoustic crossover point is around 1850 Hz. The power response and directivity index look relatively smooth to me for a passive crossover.
The woofer rolls off early because there is no port in the simulation. It should be flat down to 100 Hz or so with the addition of a port. Subwoofers will be used below that point. Sensitivity is around 89 db/2.83V.
I'm a bit concerned about the impedance plot though. Both drivers are nominal 8 ohm drivers. The black trace is the impedance after the crossover applied. The red and green lines are the raw impedances of the woofer and CD respectively (please ignore the wiggles; they're artifacts of the automatic conversion of impedance plots from driver spec PDFs).
Finally, the purple trace is the EPDR, and it looks a bit low at around 3 ohms for most of the mid-range. Is this normal?
Please let me know what you think about the crossover. Any advice will be appreciated.
The on-axis in-room measured response of the CD+horn is below (1/12 octave smoothing):
I used a first order crossover @ 8000 Hz for the CD to get a relatively flat frequency response so that I can get away with a single notch filter centered at 1000 Hz with Q value of 1. There's also an L-pad to reduce the CD level. The crossover for the woofer is a simple second-order at 1100 Hz. The actual acoustic crossover point is around 1850 Hz. The power response and directivity index look relatively smooth to me for a passive crossover.
The woofer rolls off early because there is no port in the simulation. It should be flat down to 100 Hz or so with the addition of a port. Subwoofers will be used below that point. Sensitivity is around 89 db/2.83V.
I'm a bit concerned about the impedance plot though. Both drivers are nominal 8 ohm drivers. The black trace is the impedance after the crossover applied. The red and green lines are the raw impedances of the woofer and CD respectively (please ignore the wiggles; they're artifacts of the automatic conversion of impedance plots from driver spec PDFs).
Finally, the purple trace is the EPDR, and it looks a bit low at around 3 ohms for most of the mid-range. Is this normal?
Please let me know what you think about the crossover. Any advice will be appreciated.
