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🙂
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🙂
Dude i always seem to put my posts in the wrong place but its fuzzy topics. Yours is definetly electronics.
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.
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.
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.
jimbo1968 said:
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?
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 ??
Who is Mingus ??
audio-kraut said:
im not jimbo but...
its all about Beethoven, Liszt, the doors, Hendrix and some times TCM.
audio-kraut said:
I asked, not Jimbo and it might be because he died when i was still playing outside in a park with other preteens old man
😀Re: Re: Active crossover questions
I will look up differential.
Now however I'm thinking of a bi-amp design with passive crossover of High and Mid. My thinking is that if I need a series capacitor to protect the tweeter in a tri-amp set-up, and if the the passive crossover for a tweeter is a series capacitor then where's the advantage? This is easy to implement as a neat 1 box design
Tri-amp vs bi-amp anyone? On the ESP site the bi-amp article is written as though tri-amp is not much advantage, then the tri-amp article seems to suggest that it is.
I guess I can do bi-amp and then upgrade to tri-amp. (which would be easy with the DCX!!!Damn... wish I could make a decision and get on with it)
soongsc said:
I will look up differential.
I was planning to split the filters between separate amp cases.Bill Fitzpatrick said:
Now however I'm thinking of a bi-amp design with passive crossover of High and Mid. My thinking is that if I need a series capacitor to protect the tweeter in a tri-amp set-up, and if the the passive crossover for a tweeter is a series capacitor then where's the advantage? This is easy to implement as a neat 1 box design
Tri-amp vs bi-amp anyone? On the ESP site the bi-amp article is written as though tri-amp is not much advantage, then the tri-amp article seems to suggest that it is.
I guess I can do bi-amp and then upgrade to tri-amp. (which would be easy with the DCX!!!Damn... wish I could make a decision and get on with it)
Re: Re: Re: Active crossover questions
I sort of simplified the expression when I said differential. I was thinking subtracting the high pass and the low pass from the full pass portion.
Ribbons commonly use a cap to prevent low frequencies from flapping them around. It also creates some phase shift you probably would want to consider.
I think you're asking for a really diversed response when you ask biamp or triamp, someone might just tell you to do an array. I really depends on what kind of drivers you want to use and the size of the room, your music preference, and look preference.
You could also do a triamp and mod the frequencies to biamp as well.😀
jimbo1968 said:
I sort of simplified the expression when I said differential. I was thinking subtracting the high pass and the low pass from the full pass portion.
Ribbons commonly use a cap to prevent low frequencies from flapping them around. It also creates some phase shift you probably would want to consider.
I think you're asking for a really diversed response when you ask biamp or triamp, someone might just tell you to do an array. I really depends on what kind of drivers you want to use and the size of the room, your music preference, and look preference.
You could also do a triamp and mod the frequencies to biamp as well.😀
Re: Re: Re: Re: Active crossover questions
But the slopes out of the subtractor aren't 4th order and that could be an issue.
soongsc said:
But the slopes out of the subtractor aren't 4th order and that could be an issue.
Re: Re: Re: Re: Re: Active crossover questions
True.
Some people just go by the brand name, and some look into the guts to determine value. There are lots of valueable things in life that go unnoticed.
Bill Fitzpatrick said:
True.
Some people just go by the brand name, and some look into the guts to determine value. There are lots of valueable things in life that go unnoticed.
jimbo1968 said:
If you want to put them in separate boxes, you need to add a buffer to each of the inputs to the box.
Re: Re: Active crossover questions
In the example: "Four op amps, IC1a, IC1b, IC5a & IC5b, act as input or output buffers while the remaining eight op amps......."
So, I don't mind having an input buffer before every bandpass filter, it does not look like it is necessary.
But there may be an advantage??
Also a buffer in each amplifier fits with my 'modular' approach. Bypassing the filters leaves me with 3 buffered chipamps (stereo if I wire another input, or mono if I parallel or bridge the amps)
soongsc said:
In the example: "Four op amps, IC1a, IC1b, IC5a & IC5b, act as input or output buffers while the remaining eight op amps......."
So, I don't mind having an input buffer before every bandpass filter, it does not look like it is necessary.
But there may be an advantage??
Also a buffer in each amplifier fits with my 'modular' approach. Bypassing the filters leaves me with 3 buffered chipamps (stereo if I wire another input, or mono if I parallel or bridge the amps)
So I need to design a pcb with input buffer, 24db hi pass, 24db low pass, output buffer/gain control.
How big will such a PCB be?
What will the rough cost of components be for each of those?
How big will such a PCB be?
What will the rough cost of components be for each of those?
crossover frequencies
What is the ideal target for music (ie don't worry about Movie effects).
Based on reading the ESP Bi-amp article, how about something like:
Low: 40 - 300 (8" in 40l sealed)
Mid: 300 - 3000
High: 3000 - 20K
If music doesn't need to go very low, I will use a separate subwoofer for effects below 40Hz !
What is the ideal target for music (ie don't worry about Movie effects).
Based on reading the ESP Bi-amp article, how about something like:
Low: 40 - 300 (8" in 40l sealed)
Mid: 300 - 3000
High: 3000 - 20K
If music doesn't need to go very low, I will use a separate subwoofer for effects below 40Hz !
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