Active crossover questions

jimbo1968 · 12th June 2005, 05:09 PM

I plan to build 3way active front speakers, and although using a dcx2496 would be the easy option I would like to build the following if its not too much trouble/cost and can still be flexible.

I've got 3 stereo chipamp kits which will go into a box each and I was thinking I could put a band pass filter into each amp, with adjustable frequencies and gain. It doesn't matter if this costs more than using a dcx2496, but I'm thinking it should cost about the same as building a separate 6way Xover?

What I'd like advice on is what filters to use (and why). I must admit that I don't understand what the phase considerations are at crossover.

What if I just copy this design? http://www.siliconchip.com.au/cms/A_30278/article.html
Feeding the signal from one amp to the next.

Can I add a trim pot into the output opamp to adjust the gain for each of the drivers?

I'd like confirmation that this is feasible! The fact that I haven't found a previous example makes me worry that for some reason it's a dumb idea.

Also, my plan for setting all this up is to play pink noise and use RTA software to view the output!

And finally, how do I protect my tweeter from the amp switch on/off? Is it as simple as a capacitor in series?

Lot's of questions I know, but this way I may get some bites

Madmike2 · 12th June 2005, 08:51 PM

Dude i always seem to put my posts in the wrong place but its fuzzy topics. Yours is definetly electronics.

jimbo1968 · 12th June 2005, 09:22 PM

I am wondering where all the active fans are. A search on active crossover gives most hits for 'loudspeakers' and none (on the first) page for electronics.

Madmike2 · 13th June 2005, 12:36 AM

Solid state guys not discussing these at all ? And what one were you thinking of buying? I say get a DBX 3way. The Rane is nice to but S/N is alittle low.

soongsc · 13th June 2005, 12:47 AM

If you design a high pass, a low pass, and a differential for the mid, it would be a much cleaner design. For 6 way, well take the low pass and do it again. Lot less OPAMPS.

Bill Fitzpatrick · 13th June 2005, 01:23 AM

Quote:

Originally posted by jimbo1968

What if I just copy this design? http://www.siliconchip.com.au/cms/A_30278/article.html

Can I add a trim pot into the output opamp to adjust the gain for each of the drivers?

It looks like a good design to me. Id just copy it. The ariticle says there are no output adjustments but VR1-3 look just like that. I didn't read the whole thing. Are they offering boards?

Madmike2 · 13th June 2005, 01:29 AM

Ya it looks like it comes with the board as well, complete kit unassembled. Hell 'I' might even be able to build it. ANd it is not a computer

Who is Mingus ??

Bill Fitzpatrick · 13th June 2005, 01:37 AM

Quote:

Who is Mingus ??

http://www.mingusmingusmingus.com/main/mingus.htm

audio-kraut · 13th June 2005, 04:17 AM

@jimbo 1968 - if you don't know mingus, why do you build speakers?

killerfishes · 13th June 2005, 04:48 AM

Quote:

Originally posted by audio-kraut
@jimbo 1968 - if you don't know mingus, why do you build speakers?

im not jimbo but...
its all about Beethoven, Liszt, the doors, Hendrix and some times TCM.

12th June 2005, 05:09 PM	#1
jimbo1968 diyAudio Member Join Date: Nov 2004 Location: UK, bristol	Active crossover questions I plan to build 3way active front speakers, and although using a dcx2496 would be the easy option I would like to build the following if its not too much trouble/cost and can still be flexible. I've got 3 stereo chipamp kits which will go into a box each and I was thinking I could put a band pass filter into each amp, with adjustable frequencies and gain. It doesn't matter if this costs more than using a dcx2496, but I'm thinking it should cost about the same as building a separate 6way Xover? What I'd like advice on is what filters to use (and why). I must admit that I don't understand what the phase considerations are at crossover. What if I just copy this design? http://www.siliconchip.com.au/cms/A_30278/article.html Feeding the signal from one amp to the next. Can I add a trim pot into the output opamp to adjust the gain for each of the drivers? I'd like confirmation that this is feasible! The fact that I haven't found a previous example makes me worry that for some reason it's a dumb idea. Also, my plan for setting all this up is to play pink noise and use RTA software to view the output! And finally, how do I protect my tweeter from the amp switch on/off? Is it as simple as a capacitor in series? Lot's of questions I know, but this way I may get some bites

12th June 2005, 08:51 PM	#2
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Dude i always seem to put my posts in the wrong place but its fuzzy topics. Yours is definetly electronics. __________________ Persistence is better then intelligence. Unless persistence kills you.

13th June 2005, 12:36 AM	#4
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Solid state guys not discussing these at all ? And what one were you thinking of buying? I say get a DBX 3way. The Rane is nice to but S/N is alittle low. __________________ Persistence is better then intelligence. Unless persistence kills you.

13th June 2005, 12:47 AM	#5
soongsc diyAudio Member Join Date: Mar 2005 Location: Taiwan	If you design a high pass, a low pass, and a differential for the mid, it would be a much cleaner design. For 6 way, well take the low pass and do it again. Lot less OPAMPS. __________________ Hear the real thing!

13th June 2005, 01:29 AM	#7
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Ya it looks like it comes with the board as well, complete kit unassembled. Hell 'I' might even be able to build it. ANd it is not a computer Who is Mingus ?? __________________ Persistence is better then intelligence. Unless persistence kills you.


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12th June 2005, 09:22 PM	#3
jimbo1968 diyAudio Member Join Date: Nov 2004 Location: UK, bristol	I am wondering where all the active fans are. A search on active crossover gives most hits for 'loudspeakers' and none (on the first) page for electronics.

13th June 2005, 04:17 AM	#9
audio-kraut diyAudio Member Join Date: Apr 2004 Location: 12km off the alaska highway in northern BC	@jimbo 1968 - if you don't know mingus, why do you build speakers?

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