It may be appropriate to post this schematic here, which is an older version of Mr. Pass crossover (PCX). Additional info, with module pics can be found here: http://www.diyaudio.com/forums/showthread.php?s=&postid=37444#post37444
I've been thinking about an active crossover for years, somehow never build a good one though. Probably because of Fred's thread, I'll be able to do it now
I've been thinking about an active crossover for years, somehow never build a good one though. Probably because of Fred's thread, I'll be able to do it now
Attachments
Divide and conquer
You should have a unity gain buffer between the first order and second order section to prevent tuning one network from
changing the response of the other. Some
of the cookbook component values take in to account the interaction between the first and second order networks in the formulas but I think the intereaction could be a problem when trying to tune the first and second order sections to have different corner frequencies from each other.
You should have a unity gain buffer between the first order and second order section to prevent tuning one network from
changing the response of the other. Some
of the cookbook component values take in to account the interaction between the first and second order networks in the formulas but I think the intereaction could be a problem when trying to tune the first and second order sections to have different corner frequencies from each other.
> You should have a unity gain buffer between the first order and second order section to prevent tuning one network from
changing the response of the other. ...I think the intereaction could be a problem...
For hand-tweaking a filter today, I agree. A buffer sure makes things easier.
But back in 1988, op-amps cost money and good audio op-amps were expensive (see inset in Peter's post; these were discrete hand-built hand-trimmed units). More design pencil was a good trade-off for fewer amplifiers.
BTW: Thanks for the thread.
changing the response of the other. ...I think the intereaction could be a problem...
For hand-tweaking a filter today, I agree. A buffer sure makes things easier.
But back in 1988, op-amps cost money and good audio op-amps were expensive (see inset in Peter's post; these were discrete hand-built hand-trimmed units). More design pencil was a good trade-off for fewer amplifiers.
BTW: Thanks for the thread.
Fred,
Thanks for the resistor matrix. Good job.
There have been Active Crossovers started in the past but none that I know of have gained enough momentum to finish. I've ordered some 2sk389 and 2sk170 to experiment with and gain some more knowledge. I dont know what Nelson has in store for his active crossover, but a PCB offering is something I would be interested in, or at least a layout to use for etching my own.
Most of all I wanted to bring this thread back to the top so it won't lose all its momentum.
BDP
Thanks for the resistor matrix. Good job.
There have been Active Crossovers started in the past but none that I know of have gained enough momentum to finish. I've ordered some 2sk389 and 2sk170 to experiment with and gain some more knowledge. I dont know what Nelson has in store for his active crossover, but a PCB offering is something I would be interested in, or at least a layout to use for etching my own.
Most of all I wanted to bring this thread back to the top so it won't lose all its momentum.
BDP
It also says that "the cone drivers are direct coupled to the amplifiers with no intervening passive circuitry". Does that mean that Raven tweater is capacitively coupled to the amp for protection?
I found Rushmore literature very enlightening and will modify my main speakers into a similar setup
I found Rushmore literature very enlightening and will modify my main speakers into a similar setup
It also says with no feedback, Followers? Does passive mean between buffers? With the drive capability of the BOSOZ could you drive a passive filter for the midrange and buffer the other high and lowpass filters. So many possibilities and the circuit hasnt even been built yet.
I have to agree with what an earlier post said. That we try to keep the signal path as short as possible then we add all this circuitry for an active x-over. A simple passive for the right midrange seems like a good compromise.
I have to agree with what an earlier post said. That we try to keep the signal path as short as possible then we add all this circuitry for an active x-over. A simple passive for the right midrange seems like a good compromise.
Yes,
The question for me is do I need gain to equalize the drivers or if the amplifier gains are not the same. Do I want the ability to change x-over points with out effecting each of the filters. If you build another amp this kind of versitility/ adjustability would be nice.
See what happens when you build too many amps??
The question for me is do I need gain to equalize the drivers or if the amplifier gains are not the same. Do I want the ability to change x-over points with out effecting each of the filters. If you build another amp this kind of versitility/ adjustability would be nice.
See what happens when you build too many amps??
My idear for an active xover
Hi all,
I have made a plan for an active xover, but I need to make sure that I have included all I need for a flexible filter.
Please see the pic and comment on it.
It's a 4 way filter using 2 global EQ's and some EQ's in sub, bass, and midrange.
Thanks for any input.
Jens
Hi all,
I have made a plan for an active xover, but I need to make sure that I have included all I need for a flexible filter.
Please see the pic and comment on it.
It's a 4 way filter using 2 global EQ's and some EQ's in sub, bass, and midrange.
Thanks for any input.
Jens
Attachments
SMD or normal resistors
Hi,
What would be best, SMD resistors or normal ones that need drilling?
SMD gives a smaller layout, but are difficult for most DIY folks to get. Normal resistors are alot bigger and more easy to come by.
Is there any difference in sound?
Are PP caps ok for sound?
What about OPamps, what do you prefer?
Thanks
\Jens
Hi,
What would be best, SMD resistors or normal ones that need drilling?
SMD gives a smaller layout, but are difficult for most DIY folks to get. Normal resistors are alot bigger and more easy to come by.
Is there any difference in sound?
Are PP caps ok for sound?
What about OPamps, what do you prefer?
Thanks
\Jens
3 way stereo Active Crossover summarize
Hi,
Can anyone summarize things about building/buying active crossover of 3way-stereo (including performance and costs).
I want to upgrade my hi-end speakers (which I build and designed) with such a crossver and amps.
The crossover should have flexibility (freq, slopes, att) to support future use in other speakers design as I will want to use it for speaker designs (for my personal use).
Thanks!
Hi,
Can anyone summarize things about building/buying active crossover of 3way-stereo (including performance and costs).
I want to upgrade my hi-end speakers (which I build and designed) with such a crossver and amps.
The crossover should have flexibility (freq, slopes, att) to support future use in other speakers design as I will want to use it for speaker designs (for my personal use).
Thanks!
Jens' active thread on analog crossover is here:
http://www.diyaudio.com/forums/showthread.php?threadid=27046&perpage=15&pagenumber=1
There is also moamps' project, which is a different take on the same basic idea:
http://www.diyaudio.com/forums/showthread.php?threadid=27651
I must admit that I am currently organizing a group buy on a design that arose out of moamps' project. I think it is excellant in terms of tweaking/forward compatibility.
http://www.diyaudio.com/forums/showthread.php?threadid=32095&perpage=15&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?threadid=27046&perpage=15&pagenumber=1
There is also moamps' project, which is a different take on the same basic idea:
http://www.diyaudio.com/forums/showthread.php?threadid=27651
I must admit that I am currently organizing a group buy on a design that arose out of moamps' project. I think it is excellant in terms of tweaking/forward compatibility.
http://www.diyaudio.com/forums/showthread.php?threadid=32095&perpage=15&pagenumber=1
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