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Need help wiring replacement high-pass filter for Avatar cabinet mod

D

daveman50

Supporting Member
Feb 24, 2007
1,976
2,140
Albany NY
#1
I'm (finally) replacing the tweeter in an old Avatar SB112 cabinet with a 6" midrange (Eminence LA6-CBMR). I've pulled the old Avatar "crossover" (high pass filter), which is mounted on the input panel, and I want to hook up the new filter, which is an Eminence PXB:1k6. (The woofer wire is going off to the left, the tweet to the right. But you knew that.)

(1) How do I hook up the new unit? I mean, exactly what goes where? -- which wires to cut, which wires to solder where, etc. I can solder, etc., but this just looks like spaghetti to me.

(2) Any advice on how to physically install the new unit?

Thanks much for the advice.
 

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#11
Daveman50, that's a high pass filter that will bring your midrange driver in at 1.6 KHz, where the woofer still has plenty of output. You need to get the 2-way crossover so that the woofer is low-passed and doesn't overlap the midrange driver.
 
#12
I've just followed the advice of billfitzmaurice and others as to what the necessary components are to make this mod work. This is what I've got and I'm going with it. If you can help me wire it up, I'd appreciate it.

PS, the woofer is an Eminence Delta 12LF (not neo).
 
#13
Don't touch the wiring for the woofer. The filter goes inbetween the 6" and the wiring coming out of the lpad, going to the tweeter. Remove the old cap. Connect +wires to plus connections. If you can't see wich wires are +, check how the old tweeter was connected.

What alway confuses me on these factory boards is wether they already factored in the phase reversal of the filter in the +\- markings. You might have to try reversing the + and - if you think your midrange is lacking around the x-over freq.

For mounting the board a good way is to screw it to the back wall. But with slightly dampening (i.e. Rubber) spacers inbetween.

Does this help?
 
#14
Matthijs said:
Does this help?
Click to expand...

Thanks. Yes, it does, but I have a few more questions.

The tweeter currently is connected to an attenuator. I've been assuming that I will be disconnecting the attentuator from this circuit, and that I could remove the attenuator completely (as long as I plug the hole).

The current wiring is that the tweeter's + lead (white line) is connected to the attenuator (middle lug) and then there's another lead off of the attenuator to the speaker input. The tweeter's - lead is connected to the speaker input. The old filter is between the attenuator and the speaker in; I will disconnnect and remove that.

The PXB unit has T+/T- and IN+/IN- lugs. What do I connect to each/which of these, both in and out?

Thanks!
 
#15
Matthijs said:
Don't touch the wiring for the woofer. The filter goes inbetween the 6" and the wiring coming out of the lpad, going to the tweeter. Remove the old cap. Connect +wires to plus connections. If you can't see wich wires are +, check how the old tweeter was connected.

What alway confuses me on these factory boards is wether they already factored in the phase reversal of the filter in the +\- markings. You might have to try reversing the + and - if you think your midrange is lacking around the x-over freq.

For mounting the board a good way is to screw it to the back wall. But with slightly dampening (i.e. Rubber) spacers inbetween.

Does this help?
Click to expand...

The old crossover wouldn't have had any polarity reversal but a 12dB/octave filter would. This new crossover looks like a 3rd-Order filter, which would stay the same as it is now.

The crossover doesn't connect to the output of the L-Pad, it goes before it.
 
#16
daveman50 said:
Thanks. Yes, it does, but I have a few more questions.

The tweeter currently is connected to an attenuator. I've been assuming that I will be disconnecting the attentuator from this circuit, and that I could remove the attenuator completely (as long as I plug the hole).

The current wiring is that the tweeter's + lead (white line) is connected to the attenuator (middle lug) and then there's another lead off of the attenuator to the speaker input. The tweeter's - lead is connected to the speaker input. The old filter is between the attenuator and the speaker in; I will disconnect and remove that.

The PXB unit has T+/T- and IN+/IN- lugs. What do I connect to each/which of these, both in and out?

Thanks!
Click to expand...

Leave the L-pad- you won't have a way to balance the levels if you remove it. An L-pad presents a fairly constant load, regardless of its position and that's why they use them for mid/tweeter level controls.

They used hot glue- if you want to use the same, go ahead. If the back panel is thick enough, I would screw it to that, next to the plastic plate.

Look at the photo- the L-Pad terminals are, from left to right, IN, Out, Common. You need to deal with only the one with the cap attached to it.

1) Solder a piece of wire to the crossover's IN + and IN - terminals
2) Disconnect the tweeter's - wire from the jack and move it to the new crossover's T- terminal.
3) Remove the yellow capacitor and connect the T+ wire to the point where the yellow capacitor was soldered to the L-Pad.
4) Connect the IN + wire to the point on the jack where the yellow capacitor was attached.
5) Connect the IN - wire to the same point as the existing tweeter's - wire.

You absolutely must connect the IN + and - wires correctly. Mount the crossover securely. Put the plate back in and you're done.

Did you get a circuit diagram or specs with this crossover? Post a link if you have one.
 
#18
1958Bassman said:
Leave the L-pad- you won't have a way to balance the levels if you remove it. An L-pad presents a fairly constant load, regardless of its position and that's why they use them for mid/tweeter level controls.

They used hot glue- if you want to use the same, go ahead. If the back panel is thick enough, I would screw it to that, next to the plastic plate.

Look at the photo- the L-Pad terminals are, from left to right, IN, Out, Common. You need to deal with only the one with the cap attached to it.

1) Solder a piece of wire to the crossover's IN + and IN - terminals
2) Disconnect the tweeter's - wire from the jack and move it to the new crossover's T- terminal.
3) Remove the yellow capacitor and connect the T+ wire to the point where the yellow capacitor was soldered to the L-Pad.
4) Connect the IN + wire to the point on the jack where the yellow capacitor was attached.
5) Connect the IN - wire to the same point as the existing tweeter's - wire.

You absolutely must connect the IN + and - wires correctly. Mount the crossover securely. Put the plate back in and you're done.

Did you get a circuit diagram or specs with this crossover? Post a link if you have one.
Click to expand...

+1 to this.
This is a diagram drawing for the Eminence L-pad and crossover. It is a bit different than what 1958bassman described, but it still is basically the same basic path and may be of some help to illustrate the general scheme.
Hope that helps a bit, and best of luck.

px-lpad--wiring-size650.gif
 
#19
daveman50 said:
OK, Jim, you're done! Next!

I'm just hoping that Passinwind will notice this thread and tell me what to do.
Click to expand...

Looks like a few guys have already beaten me to it. In my own builds I would probably use a fixed attenuator if needed/desired, because the cheap commercial variable ones are not really all that close to a constant load. Sometimes that matters a lot, sometimes it doesn't. You are crossing over high enough that power handling won't be a huge concern, at least.
 
#20
Passinwind said:
Looks like a few guys have already beaten me to it. In my own builds I would probably use a fixed attenuator if needed/desired, because the cheap commercial variable ones are not really all that close to a constant load. Sometimes that matters a lot, sometimes it doesn't. You are crossing over high enough that power handling won't be a huge concern, at least.
Click to expand...

Thanks! I'm on my way-- should be done this afternoon. I can take out the attenuator later if it isn't making it.
 

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