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Multi-Way Conventional loudspeakers with crossovers

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Old 22nd October 2012, 11:50 PM   #401
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Quote:
Originally Posted by flavio81 View Post
BTW having read about the non-linear effects of some capacitor types in audio, sometimes i wonder if the inductor isn't such an "evil" component.
Like capacitor with air or vacuum dielectric is no more evil than a coil without magnetic core. But if you add a core to the coil it is more evil than dielectric in the capacitor.
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Old 23rd October 2012, 12:13 AM   #402
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Quote:
Originally Posted by planet10 View Post
What you describe is a powered speaker. It can be active or passive.
Powered speaker can be passive, if power is used to create constant magnetic field only. But speaker with the amp inside can't be passive. I did not describe powered speaker. I described exactly active speaker.
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Old 23rd October 2012, 12:27 AM   #403
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Originally Posted by planet10 View Post
For the size required they almost have to be cored and it is far from trivial... calculate the value needed for 1st order into 100k impedance.
Go lower impedance and then the value is reduced proportionately. But don't go too low or losses become significant. I've started playing with passive line level LC quite recently and an impedance of 100-200 ohms seems to work. But its very early days yet in winding my own inductors - perhaps longer term stability is going to be an issue. I'm not using air-core as one of my values is 11.4mH

@Wave - what's the SRF of the primary of your 12H trafo? IOW, what's the parasitic shunt capacitance? Also what core material?
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Old 23rd October 2012, 12:35 AM   #404
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Quote:
Originally Posted by abraxalito View Post
Go lower impedance and then the value is reduced proportionately.
I know that, but that is the input impedance of my amps. I'm not going to change that.

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Old 23rd October 2012, 12:36 AM   #405
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Originally Posted by Wavebourn View Post
Powered speaker can be passive
Yes it can. Lots of cheap storebout monitor speakers that are 1 amp channel built in driving a 2-way with a passive XO.

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Old 23rd October 2012, 12:41 AM   #406
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Quote:
Originally Posted by planet10 View Post
Yes it can. Lots of cheap storebout monitor speakers that are 1 amp channel built in driving a 2-way with a passive XO.
Then they are active speakers.

Honestly, I don't like this terminology, even if it is domestic. It is confusing, artificial. Call me anti-patriot, but I prefer international terminology accepted by the outside of the forum world.
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Old 23rd October 2012, 12:42 AM   #407
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I know that, but that is the input impedance of my amps. I'm not going to change that.
Looks like you're not really cut out for passive LC then
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Old 23rd October 2012, 12:43 AM   #408
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Dave, you can just add the lower impedance parallel to the input impedance of your power amps.(not change the amp itself)
I have have even built at three-way like this, where I took the signal over a 20 ohm resistor (serial filter) posing as the basedriver in a system with powered woofer.
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Old 23rd October 2012, 12:49 AM   #409
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Originally Posted by abraxalito View Post
@Wave - what's the SRF of the primary of your 12H trafo? IOW, what's the parasitic shunt capacitance? Also what core material?
I don't remember. But core material is fantastic! Huge inductance for such tiny size.
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Old 23rd October 2012, 12:50 AM   #410
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Is it commercially available or a 'special' ?
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