Passive Crossover questions

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J_Dunavin
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Passive Crossover questions

#1 Post by J_Dunavin » Sun Sep 12, 2021 3:04 pm

I Bi-Amped my DRs even though they had Piezo arrays, not for performance gains, but I liked to turn down the gain on them.
For simplicity sake (one less amp to haul around) I'm wiring my new Otop8s (CD not piezo this time) with a passive, BUT I want the ability to bi amp in the future, should I feel the itch to do so.
I'm sure this wouldn't normally be recommended, but will this work? I've seen other commercial cabs with a bi-amp and normal inputs...
Was also thinking about adding a Zobel filter to the mids? Probably not recommended if Bill didn't put it in the plans...
And was also thinking about a fixed L-Pad for the highs? I suppose the answer to that would be to just EQ down the highs if they are too much?

Thanks for letting my kick the can around....
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crossover.jpg
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

Bruce Weldy
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Location: New Braunfels, TX

Re: Passive Crossover questions

#2 Post by Bruce Weldy » Sun Sep 12, 2021 3:43 pm

On the NL4 for the passive - you'd only have two wires coming into the crossover (full range).

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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J_Dunavin
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Re: Passive Crossover questions

#3 Post by J_Dunavin » Sun Sep 12, 2021 3:47 pm

ah yes.
Now I can plug a 2 pole speakon cable into a 4 pole jack, but not the other way around, right?
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

Bruce Weldy
Posts: 7659
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Passive Crossover questions

#4 Post by Bruce Weldy » Sun Sep 12, 2021 4:39 pm

J_Dunavin wrote:
Sun Sep 12, 2021 3:47 pm
ah yes.
Now I can plug a 2 pole speakon cable into a 4 pole jack, but not the other way around, right?
Yes.....always use the 4 pole jack and either the NL4 or NL2.....stay away from the old 2 pole jacks and plugs. Those suck....

https://www.parts-express.com/Neutrik-N ... nt-092-052

https://www.parts-express.com/Neutrik-N ... nt-092-198

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: Passive Crossover questions

#5 Post by Seth » Sun Sep 12, 2021 11:19 pm

J_Dunavin wrote:
Sun Sep 12, 2021 3:04 pm
I Bi-Amped my DRs even though they had Piezo arrays, not for performance gains, but I liked to turn down the gain on them.
For simplicity sake (one less amp to haul around) I'm wiring my new Otop8s (CD not piezo this time) with a passive, BUT I want the ability to bi amp in the future, should I feel the itch to do so.
I'm sure this wouldn't normally be recommended, but will this work? I've seen other commercial cabs with a bi-amp and normal inputs...
Was also thinking about adding a Zobel filter to the mids? Probably not recommended if Bill didn't put it in the plans...
And was also thinking about a fixed L-Pad for the highs? I suppose the answer to that would be to just EQ down the highs if they are too much?

Thanks for letting my kick the can around....
I'm fairly certain you'll need to put a switch in that isolates the crossover from at least one of the drivers when in bi-amp mode. Otherwise, the two amps will be connected through the crossover circuits.

On second thought, you might be able to just put a switch on the input side of the crossovers that simply disconnects the inputs of the crossovers from each other. But, I have no idea whether the crossover circuits would alter the sound by just having their outputs connected to the speakers or not. If not, I think this would be the simplest solution.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Rune Bivrin
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Re: Passive Crossover questions

#6 Post by Rune Bivrin » Mon Sep 13, 2021 4:28 am

For any crossover steeper than 6dB/octave, you'll need to disconnect the drivers from the crossover. Otherwise, the amps will "see" the drivers in parallel with extra components, which may cause substantial problems.
In build order:
O12 with no tweeter.
3 x WedgeHorns.
2 x Jack 10 without tweeters.
2 x DR250.
2 x 16" T39
1 x Tuba 24
2 x SLA Pro (sort of...)

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J_Dunavin
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Re: Passive Crossover questions

#7 Post by J_Dunavin » Mon Sep 13, 2021 6:36 am

Rune Bivrin wrote:
Mon Sep 13, 2021 4:28 am
For any crossover steeper than 6dB/octave, you'll need to disconnect the drivers from the crossover. Otherwise, the amps will "see" the drivers in parallel with extra components, which may cause substantial problems.
Ahhh yes I didn’t think about components being parallel across the coil of the speakers.

Thanks for the input guys!
8 - DR200
2 - DR250
9 - T24
6 - T45
1 - Auto Tuba

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