My questions are:
Which drivers need the BSC?
How to measure the “z-offset” and which ones need it?
I am working on a set of three way tower speakers using the ScanSpeak Discovery Drivers. I am using the following drivers:
ScanSpeak Discovery D2608/9130 1" Textile Dome HDS Tweeter.
Scanspeak 18W/8434G-00 Discovery, 7" Midwoofer (18 cm).
Scanspeak 22W/8534G00 Discovery 8" Woofer (22 cm).
I am taking inspiration (and some liberty) from Troels Gravesen’s “ScanSpeak Discovery 861.” That is the reason for the drivers I am using and the basis for the cabinets I intend to make. My twist is that I am going to put an “Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer” in each tower in their own enclosures at the base. I have already built a subwoofer using one of these drivers and was impressed with the output. The subwoofers will be ported and run together powered by an external amplifier so the crossover will not need to provide signal for the Epiques.
I have started building a test box as a full scale mockup of the speakers to test the configuration. The woofer will have its own ported chamber (above the sub), and the mid woofer and tweeter will be in an enclosed chamber at the top of the cabinet. I am going to experiment with having the subwoofer forward facing and downward facing (the subwoofer I made using the Epique sub produced the best sound in my room when it was downward firing). The baffle is in two pieces for the test box, that way I can swap out baffles to test subwoofer configuration.
The cabinets will be ¾ inch plywood and the baffle will be one inch thick plywood. The subs get two inch round ports, and the woofer gets a three inch round port.
I am asking for crossover design help. I realize that to really tune the speakers properly, I need to get frd and zma files from the actual drivers and I plan on doing that as soon as I get the baffles made and the holes for the drivers cut out. I will run frequency sweeps in the actual test box. The woofer, mid and tweeter will all be on the same common baffle and I will flush mount them. And counter to what people recommend, I will line them all up on the same axis for symmetry (aesthetics). For now I’m using the frequency responses and impedance from the manufacturer’s datasheet as my test data.
I am looking for advice on the three way crossover. I have done one two-way and now I need help with the three way crossover. Specifically, with “baffle step correction (BSC)” and “z-offset.”
Any input would be greatly appreciated.
Cheers,
George, Tigard Oregon, UDA
Which drivers need the BSC?
How to measure the “z-offset” and which ones need it?
I am working on a set of three way tower speakers using the ScanSpeak Discovery Drivers. I am using the following drivers:
ScanSpeak Discovery D2608/9130 1" Textile Dome HDS Tweeter.
Scanspeak 18W/8434G-00 Discovery, 7" Midwoofer (18 cm).
Scanspeak 22W/8534G00 Discovery 8" Woofer (22 cm).
I am taking inspiration (and some liberty) from Troels Gravesen’s “ScanSpeak Discovery 861.” That is the reason for the drivers I am using and the basis for the cabinets I intend to make. My twist is that I am going to put an “Epique E180HE-44 7" DVC MMAG Extended Range Subwoofer” in each tower in their own enclosures at the base. I have already built a subwoofer using one of these drivers and was impressed with the output. The subwoofers will be ported and run together powered by an external amplifier so the crossover will not need to provide signal for the Epiques.
I have started building a test box as a full scale mockup of the speakers to test the configuration. The woofer will have its own ported chamber (above the sub), and the mid woofer and tweeter will be in an enclosed chamber at the top of the cabinet. I am going to experiment with having the subwoofer forward facing and downward facing (the subwoofer I made using the Epique sub produced the best sound in my room when it was downward firing). The baffle is in two pieces for the test box, that way I can swap out baffles to test subwoofer configuration.
The cabinets will be ¾ inch plywood and the baffle will be one inch thick plywood. The subs get two inch round ports, and the woofer gets a three inch round port.
I am asking for crossover design help. I realize that to really tune the speakers properly, I need to get frd and zma files from the actual drivers and I plan on doing that as soon as I get the baffles made and the holes for the drivers cut out. I will run frequency sweeps in the actual test box. The woofer, mid and tweeter will all be on the same common baffle and I will flush mount them. And counter to what people recommend, I will line them all up on the same axis for symmetry (aesthetics). For now I’m using the frequency responses and impedance from the manufacturer’s datasheet as my test data.
I am looking for advice on the three way crossover. I have done one two-way and now I need help with the three way crossover. Specifically, with “baffle step correction (BSC)” and “z-offset.”
Any input would be greatly appreciated.
Cheers,
George, Tigard Oregon, UDA
All of them, technically. However you shouldn’t need to worry about it if you have measurements.
All of them need it but you don’t have to worry about it if you use the right measurement technique.