When you look at active XO design, you always see that the high and the low pass have their own, separate filter.
Why not make just 1 high pass fiter for the tweeter.
For the bass speaker, just invert the high pass signal and add it to the original signal.
This makes the system immune for tolerances on parts as well.
Basically it is the same idea as a passive series filter.
Are there people who have tried this?
Why not make just 1 high pass fiter for the tweeter.
For the bass speaker, just invert the high pass signal and add it to the original signal.
This makes the system immune for tolerances on parts as well.
Basically it is the same idea as a passive series filter.
Are there people who have tried this?
Hi Kees,
take a look at this thread (and particular for posts and attachments from Charles aka "phase_accurate")
http://www.diyaudio.com/forums/showthread.php?s=&threadid=5435&perpage=15&pagenumber=1
BTW: use the forum search and You`ll find even more useful stuff on this topic😉
take a look at this thread (and particular for posts and attachments from Charles aka "phase_accurate")
http://www.diyaudio.com/forums/showthread.php?s=&threadid=5435&perpage=15&pagenumber=1
BTW: use the forum search and You`ll find even more useful stuff on this topic😉
There are a couple circuits using this technique in one of Randy Slone's books:
http://books.mcgraw-hill.com/cgi-bin/pbg/0071379290?mv_session_id=odGy96my&mv_pc=116§ioncode=ENG
What you have to remember is that a high-pass filter (for the tweeter) changes the signal's phase with respect to the original signal. You have to use an "all-pass" filter on the original signal (to shift its phase, without affecting its frequency response) in order to subtract the high-pass filter output from it.
Hope that made some sense...
http://books.mcgraw-hill.com/cgi-bin/pbg/0071379290?mv_session_id=odGy96my&mv_pc=116§ioncode=ENG
What you have to remember is that a high-pass filter (for the tweeter) changes the signal's phase with respect to the original signal. You have to use an "all-pass" filter on the original signal (to shift its phase, without affecting its frequency response) in order to subtract the high-pass filter output from it.
Hope that made some sense...
Thanks for all the replies.
The article from Pass covers is what I was looking for.
It's not clear to me why the all pass filter is needed. In the article from Pass I can't find one either.
The article from Pass covers is what I was looking for.
It's not clear to me why the all pass filter is needed. In the article from Pass I can't find one either.
Kees said:
In a subtractive XO, the derived output is always 1st order. If you add an allpass then you can get symetrical slopes... the very few comments on the sonics of the higher order symetrical XOs have been less than stellar thou...
dave
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