Condenser in tweeter line with active crossovers???

wwwn · 12:19 PM

I am in process of building 4way, precisely 2x active, with 2x passive. And wondering if I must have some kind of crossover before horn and tweeter? Maybe condenser of 14uf (1500hz,8ohm) or so in line for the case of 50/60hz humming or dc impulses when amp is turning on/off or in case of bad connection? Putting tweeter directly on an amp don't seems too smart for me...

Charles Darwin · 10th January 2012, 12:36 PM

I've been using my 4way actives for a number of years now.
They have a compression tweeter and the amp driving it right now does produce a turn-on thump but even without a cap it has never been a problem whatsoever.

On the other hand I also use a ribbon supertweeter which I protect with an 18dB/oct high pass (5kHz, the ST kicks in at 12kHz).

bobodioulasso · 10th January 2012, 12:43 PM

I use 50uf serial connected to my active filtered tweeters to protect them without interfering with the crossover.

wwwn · 11th January 2012, 02:19 AM

@Charles, Bobodioulasso
Thanks for answers...
Next.. If I decide to put condenser, it will make 90o phase shift... than, I should use inductor in woofer line to get opposite 90o for 180o difference for connection with opposite polarity?

sreten · 11th January 2012, 09:55 AM

Quote:

Originally Posted by wwwn

@Charles, Bobodioulasso
Thanks for answers...
Next.. If I decide to put condenser, it will make 90o phase shift...
than, I should use inductor in woofer line to get opposite 90o for 180o
difference for connection with opposite polarity?

Hi,

No. There is no phase shift in the active region of
the tweeter if you use a decent sized capacitor.

rgds, sreten.

Charles Darwin · 12:20 PM

Just make sure that the capacitor which protects your tweeter has its -3dB point AT LEAST one octave below where your tweeter actually kicks in.

That is to say that if your tweeter does 5kHz and up the protection cap should roll off everything below 2.5kHz

bobodioulasso · 11th January 2012, 01:54 PM

Not only the cap will protect the tweeter but also null the dc offset of the amplifier (wether there is some) allowing the tweeter to remain centered at his rest position, avoiding unwanted distortion.

wwwn · 05:33 PM

Thanks to all

there is my idea about crossovers in lo and hi active channels. What do you think?
There is no zobel or sensitivity compensation, this my is first concept.
How zobel should looks like for this configuration?
I have no much data about drivers...
What kind of box to make? I thought about compression boxes for both bass drivers - apr 40-50l for woofer and 10-15l for bass/mid...

bobodioulasso · 11th January 2012, 05:33 PM

Which drivers are these?

wwwn · 11th January 2012, 05:39 PM

ex Yugoslav, Ei nis... not to bad

I have them 15 years, its last minute for DIY))))

10th January 2012, 12:13 PM	#1
wwwn diyAudio Member Join Date: Oct 2011	Condenser in tweeter line with active crossovers??? I am in process of building 4way, precisely 2x active, with 2x passive. And wondering if I must have some kind of crossover before horn and tweeter? Maybe condenser of 14uf (1500hz,8ohm) or so in line for the case of 50/60hz humming or dc impulses when amp is turning on/off or in case of bad connection? Putting tweeter directly on an amp don't seems too smart for me... Last edited by wwwn; 10th January 2012 at 12:19 PM.

11th January 2012, 12:16 PM	#6
Charles Darwin diyAudio Member Join Date: Nov 2009 Location: Birmingham, UK	Just make sure that the capacitor which protects your tweeter has its -3dB point AT LEAST one octave below where your tweeter actually kicks in. That is to say that if your tweeter does 5kHz and up the protection cap should roll off everything below 2.5kHz Last edited by Charles Darwin; 11th January 2012 at 12:20 PM.

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10th January 2012, 12:36 PM	#2
Charles Darwin diyAudio Member Join Date: Nov 2009 Location: Birmingham, UK	I've been using my 4way actives for a number of years now. They have a compression tweeter and the amp driving it right now does produce a turn-on thump but even without a cap it has never been a problem whatsoever. On the other hand I also use a ribbon supertweeter which I protect with an 18dB/oct high pass (5kHz, the ST kicks in at 12kHz).

10th January 2012, 12:43 PM	#3
bobodioulasso diyAudio Member Join Date: May 2008	I use 50uf serial connected to my active filtered tweeters to protect them without interfering with the crossover.

11th January 2012, 02:19 AM	#4
wwwn diyAudio Member Join Date: Oct 2011	@Charles, Bobodioulasso Thanks for answers... Next.. If I decide to put condenser, it will make 90o phase shift... than, I should use inductor in woofer line to get opposite 90o for 180o difference for connection with opposite polarity?

11th January 2012, 01:54 PM	#7
bobodioulasso diyAudio Member Join Date: May 2008	Not only the cap will protect the tweeter but also null the dc offset of the amplifier (wether there is some) allowing the tweeter to remain centered at his rest position, avoiding unwanted distortion.

11th January 2012, 05:33 PM	#9
bobodioulasso diyAudio Member Join Date: May 2008	Which drivers are these?

11th January 2012, 05:39 PM	#10
wwwn diyAudio Member Join Date: Oct 2011	ex Yugoslav, Ei nis... not to bad I have them 15 years, its last minute for DIY))))