Pics of Vifa 3-way pyramid.

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navin said:
nice job!

1. would like to know ow a series XO works.

2. what is the listening ht.? Is that for teh tweeter or mid or in between both?

3. have you tried reversing the tweeter and mid positions?

1. go to

2. the listening height should IMO be level with the normal ear level seating height if that can be designed.

3. not in a 3-way, but reversing position works well if you need to for a 2-way but keep the baffle vertical, not sloped back.
to quote from ken ahern..
So as I continue my silly analogy, two groups of frequencies are coming down the path and come to the split. The high freqs look at the inductor to the right and say, "That doesn't look good!" so they head of to the left and the tweeter. Of course the low freqs (who have no resistance to inductors) reach the opposite conclusion and head to the right. When the low freqs get past the inductor, they see the cap up ahead and decide to take the cut across to the left path and face the woofer that goes with it. Meanwhile, the high freqs have just gotten past the tweeter and are quite relieved to take the cut across to the cap which offers them little resistance.

now how do extend this to second order series XOs?

to extend the analogy (based on circuit at

both freqs are coming down +

the low freqs run through L1 the high freqs run though C2.

the low freqs then dodge C1 and run through the woofer.

the high freqs. meanwhile run the tweeter and dodge the woofer (which is really a inductance) and run through C1.

say a f3 of 2000Hz
L1 = 0.68 and L2 is 0.9
C1 = 14.1 and C2 is 18.8

L1 is effectively a low pass below the f3 of a 0.68mh inductor
C2 is a high pass above the f3 of a 18.8 uf cap.
only some of the freq that have passed a 18.8 uf cap will run through C1 which is smaller and hence has a higher f3
meanwhile only those freqs that are too low to run through v1 (14.1 uf) will run through the woofer.

so the woofer low pass is L1, C1 and the tweeter high pass is C2, L2. right?
my understanding......

...which I'm not saying is right !!

is that for the tweeter, L1 acts as a lo-freq bypass and C2 acts as a lo-freq block. hence providing a 12dB slope for the tweeter (with the correct values)

for the woofer, C1 acts as a hi freq bypass and L2 acts as a hi freq block, hence 12dB also .
An externally hosted image should be here but it was not working when we last tested it.
Please keep in mind......

..... the 2nd order spreadsheet is only speculative. I don't generally use anything but 1st order (I have never blown a tweeter). I give no guarantees as to how well the spreadhseet migt work !!

Apart from that, there should be no problem using a 2nd order series with the TC's. I use a first order all the time with the P17WJ and a variety of tweeters, including the TC26.
I don't know the TC woofers or their suitability for series x-os at all though!!

If you decide to go ahead with a 2nd order series, please let me know the outcome !!

Gook Luck !!

Joined 2001
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promitheus said:
Really cool looking boxes you have there.
Specially those flame looking ones.

Andy is the master of the non-rectangular box -- i think he is allergic to them. I can't wait to see the coneheads when he gets them done (a long term challenge so we have to be patient).


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