So I've had these drivers sitting around for the better part of a year and finally decided to try simulating a crossover. I don't have measurement equipment so I'm forced to go off manufacturer data. I used FPG graph tracer and XSim. It's my first time doing this. One thing that concerns me is the low efficiency but i think this is a given considering the efficiency of the midwoofer. The other is the 9.1 ohm resistor in the BSC circuit. It seems a little high when i compare it to other designs I see. I've attached a screenshot of Xsim. Any input is welcome!
Attachments
Sorry, I guess I should have posted those too. Here they are:
https://www.scan-speak.dk/datasheet/pdf/d2104-712000.pdf
https://www.scan-speak.dk/datasheet/pdf/15w-8534t00.pdf
https://www.scan-speak.dk/datasheet/pdf/d2104-712000.pdf
https://www.scan-speak.dk/datasheet/pdf/15w-8534t00.pdf
Looks a horrible midbass to me! Scanspeak 15W/8534T00
Awful breakup at 4.5kHz. And people usually add a presence notch somewhere around 800Hz with 5" Scans to get it tonally right. That 1.2kHz dip is the usual edge resonance. SB Acoustics Satori drivers have that too.
I think you can forget simple filters.
Series filters might get you into deep water, but this sort of thing might work. Notice the RC impedance correction. You can add passive RL bafflestep:
Why resistor in parallel with inductor in low pass crossover?
Awful breakup at 4.5kHz. And people usually add a presence notch somewhere around 800Hz with 5" Scans to get it tonally right. That 1.2kHz dip is the usual edge resonance. SB Acoustics Satori drivers have that too.
I think you can forget simple filters.
Series filters might get you into deep water, but this sort of thing might work. Notice the RC impedance correction. You can add passive RL bafflestep:
Why resistor in parallel with inductor in low pass crossover?
I was digging around for a successful project with a woofer like yours. Here a ScanSpeak 15WU/4741T00.
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I think it would be worth emailing Mike Chua for the circuit. Looks like he has dealt with a similar sort of speaker with an alarming frequency response. I can guess he has impedance corrected the Fs resonance of the Morel CAT 378 waveguide tweeter to get away with a single capacitor filter.
Shouldn't be hard to adjust for an 8 ohm midbass.
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I think it would be worth emailing Mike Chua for the circuit. Looks like he has dealt with a similar sort of speaker with an alarming frequency response. I can guess he has impedance corrected the Fs resonance of the Morel CAT 378 waveguide tweeter to get away with a single capacitor filter.
Shouldn't be hard to adjust for an 8 ohm midbass.
Thanks gents (all of you). So yes, I did forget to invert polarity on the tweeter. That did the trick. However it caused the resonance on the woofer to rise again so I had to adjust everything and make the woofer 2nd order as well. You are right, system7, this isn't exactly the simplest filter. Won't be using boutique inductors that's for sure. There's still a slight rise at 4.5k but it's the best i could do.
Attachments
sardonx, I really would get that schematic from Mike Chua. I think you are groping in the dark a bit here.
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I would guess he has notched the similar woofer around 4.5kHz based on what joensd tells me. Which is what you have to do.
That would be something like 6.8uF/2.2R/0.2mH. Zobel ought to be 7.5R/10uF looking at the Scan datasheet.
Maybe a 2mH coil. 2mH and 6.8uF is often the quick and dirty filter for a 5". I'm guessing here.
Once the woofer is sorted out, the tweeter usually follows. Might be a third order with your unit. 6.8uF/0.3mH/6.8uF with some attenuation. Dunno. A third order often ends up in a similar place to a first order. And you are less time-aligned. Mike will send you it anyway. A real gentleman.
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I would guess he has notched the similar woofer around 4.5kHz based on what joensd tells me. Which is what you have to do.
That would be something like 6.8uF/2.2R/0.2mH. Zobel ought to be 7.5R/10uF looking at the Scan datasheet.
Maybe a 2mH coil. 2mH and 6.8uF is often the quick and dirty filter for a 5". I'm guessing here.
Once the woofer is sorted out, the tweeter usually follows. Might be a third order with your unit. 6.8uF/0.3mH/6.8uF with some attenuation. Dunno. A third order often ends up in a similar place to a first order. And you are less time-aligned. Mike will send you it anyway. A real gentleman.
Wolf, I tried the resistor. I couldn't get it to flatten the peak out. But I added a notch filter to the tweeter. It's pretty much doing all the work now to flatten that 4.5khz peak out. The notch filter on the woofer is helping flatten the 1-3khz range.
System7, thanks for looking that up. I might reach out to Mike and ask him for the schematic. But if I might ask, why do you think I'm groping in the dark here and won't be doing the same by trying to apply a crossover from a different speaker? Or are you just saying that it'll give me an idea to try something simpler and then play with the values until optimized? I'm skeptical, but correct me if I'm wrong!
The only issue I see now is that the crossover is 14 components. I can take out the notch filter on the woofer and still get an acceptable response and make it 11 components but I like how flat the response is.
Will this blow up my amp? lol
System7, thanks for looking that up. I might reach out to Mike and ask him for the schematic. But if I might ask, why do you think I'm groping in the dark here and won't be doing the same by trying to apply a crossover from a different speaker? Or are you just saying that it'll give me an idea to try something simpler and then play with the values until optimized? I'm skeptical, but correct me if I'm wrong!
The only issue I see now is that the crossover is 14 components. I can take out the notch filter on the woofer and still get an acceptable response and make it 11 components but I like how flat the response is.
Will this blow up my amp? lol
Attachments
Mike Chua has just sent me his "Enlightenment" loudspeaker details. What a gent. 
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I was very close to the mark on my advice. But since you can afford Scanspeak drivers, I would go the extra mile and fit a Morel CAT 378, I think it's a better way to do things. More efficient you see, because of the waveguide. So lower distortion.
Enlightenment – Scanspeak 15WU with Morel CAT378 – AmpsLab
I was very close to the mark on my advice. But since you can afford Scanspeak drivers, I would go the extra mile and fit a Morel CAT 378, I think it's a better way to do things. More efficient you see, because of the waveguide. So lower distortion.
