I did look at the links yesterday, but found it all very difficult in German. 
But maybe some progress. The left section is a third order bass then.
That makes sense for a good speaker. The tweeter filter looks like a glorified second order in the image below. I can't guess the polarity with this coaxial.
And the section below that, called "Neu" might then be a new bass section.
Which still leaves me scratching my head on a new tweeter section.
But maybe some progress. The left section is a third order bass then.
That makes sense for a good speaker. The tweeter filter looks like a glorified second order in the image below. I can't guess the polarity with this coaxial.
And the section below that, called "Neu" might then be a new bass section.
Which still leaves me scratching my head on a new tweeter section.
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Thank you guys.
I am familiar with the German thread and even had contact with the guy who posted it. But unfortunately, he only knows the part of the crossover that is responsible for the mid woofer. And due to copyright, none of the images show the whole crossover.
@Steve: Neu means new -> it only shows his modified part of the woofer crossover
I am familiar with the German thread and even had contact with the guy who posted it. But unfortunately, he only knows the part of the crossover that is responsible for the mid woofer. And due to copyright, none of the images show the whole crossover.
@Steve: Neu means new -> it only shows his modified part of the woofer crossover
My German does extend to "Neu" as it goes.
How hard can this be, really? SEAS make the coaxial Loki with a 6" bass.
SEAS Loki MkIII
To make the bass third order, you would split the 2.2mH bass coil into about 1.8mH before and 0.4mH after the capacitor. You often put a little resistor across the 0.4mH. Which might be 5 ohms here. It ends up similar.
The Loki is a 3kHz cross to the tweeter.
How hard can this be, really? SEAS make the coaxial Loki with a 6" bass.
SEAS Loki MkIII
To make the bass third order, you would split the 2.2mH bass coil into about 1.8mH before and 0.4mH after the capacitor. You often put a little resistor across the 0.4mH. Which might be 5 ohms here. It ends up similar.
The Loki is a 3kHz cross to the tweeter.
Attachments
My intuition, based on what I have seen here is something like below might work. 3kHz crossover for a 5" metal bass.
I really have no idea about polarity, but this can't be way off. The tweeter is effectively horn loaded, so the input 3.3uF capacitor is always smaller than you might expect.
I haven't attempted an 7-8kHz bass notch on the breakup.
I really have no idea about polarity, but this can't be way off. The tweeter is effectively horn loaded, so the input 3.3uF capacitor is always smaller than you might expect.
I haven't attempted an 7-8kHz bass notch on the breakup.
Attachments
I said I wasn't too sure about polarity. We don't know what KEF are doing here. My feeling is time alignment is not too big an issue with a 5" bass anyway. Can only be a couple of centimeters out even with a regular tweeter on a baffle.
It could be a BW3 alignment on the filter, which is very KEF, and that works in either polarity.
But 4 ohms is a game changer. I hadn't researched that. But usual stuff on the circuits to adjust, smaller coils and resistors, bigger capacitors. In fact, 1mH series and 10uF shunt (maybe with a bit of resistance like 2.2R added in series with the capacitor) on the bass might then do, with 3.3uF and 0.33mH and an attenuator on the (8 ohm?) tweeter.
Acoustic centre is usually the middle of the voicecoils, so you can work Z out for the Coaxial. But it's tiny relative to 3kHz wavelength of 10cms. The good news is that 5" bass is an easy speaker. So I'd get on with it.
It could be a BW3 alignment on the filter, which is very KEF, and that works in either polarity.
But 4 ohms is a game changer. I hadn't researched that. But usual stuff on the circuits to adjust, smaller coils and resistors, bigger capacitors. In fact, 1mH series and 10uF shunt (maybe with a bit of resistance like 2.2R added in series with the capacitor) on the bass might then do, with 3.3uF and 0.33mH and an attenuator on the (8 ohm?) tweeter.
Acoustic centre is usually the middle of the voicecoils, so you can work Z out for the Coaxial. But it's tiny relative to 3kHz wavelength of 10cms. The good news is that 5" bass is an easy speaker. So I'd get on with it.
You don't happen to have a picture of the crossover where the part specifications can be seen?
@Soldy, I don't know the full schematic, even if I did I'd be reluctant to share KEF's intellectual property in public. These speakers are still in production. You can't see the capacitor values as they are wrapped in some sort of damping goo in any case.
@ernperkins, I measured the drivers just out of curiosity some time ago when I first got the speakers, they are very well behaved, but I didn't record the measurements. Sorry!
@ernperkins, I measured the drivers just out of curiosity some time ago when I first got the speakers, they are very well behaved, but I didn't record the measurements. Sorry!
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