I've had those LX5 tweeter in my drawer for 25 years I've always like the liveness they can add to the room. I've decided to use them as surround in a dipole arrangement. SB13PFC Woofer back to back sharing the same enclosure. I build the enclosure and measured the response and ended up with a 10db dip at 430hz one octave wide. It is probably mutual cancellation between the two speakers.
Before i undergo cutting the top to separate the chambers, i am looking for other solutions that would not involving woodworking.
I was thinking of running one woofer like a 2.5way, cross low and skip the BSC on the xover.
Are there solutions, any idea or past experience on similar design from you you can share to remove this dip.
Regards
Before i undergo cutting the top to separate the chambers, i am looking for other solutions that would not involving woodworking.
I was thinking of running one woofer like a 2.5way, cross low and skip the BSC on the xover.
Are there solutions, any idea or past experience on similar design from you you can share to remove this dip.
Regards
The dip is caused by the half wavelength path length between the bipole woofers. I experienced this dip in my bipolar speakers as well. My MLTL with CSS FR125 full rangers have a 4-5 dB dip in the 400-500 area. As I placed the drivers one third of the way down from the top in my MLTL design the cancellation effect was closest for the horizontal direction and more spread out across the top of the enclosure. Your speaker has a close path horizontally around the box and across the top so the cancellation paths are near the same hence strong in your case.
I did an off set bipole design MLTL using CSS EL70 drivers) which has the two woofers off set on the front and rear baffle. The front woofer was setup for listening height while the rear woofer radiated close to the floor. A partition in the center of the cabinet separated the drivers so that the cancellation effect is more spread out over the frequency range.
One thing that you could try with your current setup is to place a capacitor across the rear driver which rolls off the rear radiation close to the center of cancellation frequency region and above. This would lessen the dip you have and perhaps be more pleasing.
Also check the sound within your room and listen if the dip is less audible off axis than on axis
You can search for my posts in this forum by my name to read about my bipolar experiences.
I did an off set bipole design MLTL using CSS EL70 drivers) which has the two woofers off set on the front and rear baffle. The front woofer was setup for listening height while the rear woofer radiated close to the floor. A partition in the center of the cabinet separated the drivers so that the cancellation effect is more spread out over the frequency range.
One thing that you could try with your current setup is to place a capacitor across the rear driver which rolls off the rear radiation close to the center of cancellation frequency region and above. This would lessen the dip you have and perhaps be more pleasing.
Also check the sound within your room and listen if the dip is less audible off axis than on axis
You can search for my posts in this forum by my name to read about my bipolar experiences.
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