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Author Topic: Crossover, L-Pad, Impedence, Resistance question  (Read 9936 times)

Ivan Beaver

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #20 on: November 20, 2017, 07:26:23 am »

Yes, technically you really only need to switch the positive connections to take the crossover out of the circuit.
Assuming the + of the HF is not hooked to the common of the xover.

And also assuming the crossover is a normal parallel type, and not a series type.

Yeah, the details matter.
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Ivan Beaver
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Jeff Schoonover1

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #21 on: November 20, 2017, 11:21:01 am »

Yes, technically you really only need to switch the positive connections to take the crossover out of the circuit.
I think the X-over + terminals must be taken completely off all drivers, too.  Otherwise, the X-Over will still affect the drivers.  I think I can picture doing this with a 4-pole, double throw switch.  I'll have to draw it out. 
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Tim McCulloch

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #22 on: November 20, 2017, 11:20:19 pm »

I think the X-over + terminals must be taken completely off all drivers, too.  Otherwise, the X-Over will still affect the drivers.  I think I can picture doing this with a 4-pole, double throw switch.  I'll have to draw it out.

Yes.  Completely disconnecting the transducers from the passive crossover is the best practice.
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Ivan Beaver

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #23 on: November 21, 2017, 07:28:24 am »

I think the X-over + terminals must be taken completely off all drivers, too.  Otherwise, the X-Over will still affect the drivers.  I think I can picture doing this with a 4-pole, double throw switch.  I'll have to draw it out.
But if you look at the diagram shown, there is no path for the other parts to affect the signal.

Yes they are still hooked up, but they aren't doing anything, so it is fine.

It is only when there is a path for the passive parts that it becomes an issue
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Ivan Beaver
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Jeff Schoonover1

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #24 on: November 21, 2017, 12:14:40 pm »

Well, here's a clean drawing, but without X-over removed from circuit.  I think I'd need an 8-pole to simultaneously lift the crossover connections when in Bi-Amp mode...  I'd really like to do this with one, not two switches.
« Last Edit: November 21, 2017, 12:39:35 pm by Jeff Schoonover1 »
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David Sturzenbecher

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #25 on: November 21, 2017, 01:11:54 pm »

Well, here's a clean drawing, but without X-over removed from circuit.  I think I'd need an 8-pole to simultaneously lift the crossover connections when in Bi-Amp mode...  I'd really like to do this with one, not two switches.


Could always do something like this....



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Tim McCulloch

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #26 on: November 21, 2017, 03:18:55 pm »

Well, here's a clean drawing, but without X-over removed from circuit.  I think I'd need an 8-pole to simultaneously lift the crossover connections when in Bi-Amp mode...  I'd really like to do this with one, not two switches.

You're overthinking this, the 4PDT you proposed will work just fine.

The common terminals of the switch go to the transducer; one side of the DT goes to the crossover pass band outputs, the other side of the DT goes to your HI/LOW input jacks.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Chris Grimshaw

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #27 on: November 21, 2017, 03:52:10 pm »

If you happen to keep the crossover parts connected to the driver(s), interesting things can happen to the impedance curve - you could end up with a near-short at some frequencies. A capacitor across a midbass driver, for instance, would tend towards a short at HF. That's gonna make a lot of amps unhappy.

Chris
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Mac Kerr

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #28 on: November 21, 2017, 04:16:22 pm »

You're overthinking this, the 4PDT you proposed will work just fine.

The common terminals of the switch go to the transducer; one side of the DT goes to the crossover pass band outputs, the other side of the DT goes to your HI/LOW input jacks.

That will switch the transducers between their 2 sources, but it leaves the input to the crossover in circuit as an additional load on the amplifier when in biamp mode. If this is not a problem a single 4PDT is the way to go. Be sure it has a sufficient AC current rating.

Mac
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Mac Kerr

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Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #29 on: November 21, 2017, 04:18:04 pm »

Well, here's a clean drawing, but without X-over removed from circuit.  I think I'd need an 8-pole to simultaneously lift the crossover connections when in Bi-Amp mode...  I'd really like to do this with one, not two switches.

Shouldn't the minus side of the input to the crossover come from the #1 minus contact on the speakon?

Mac
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ProSoundWeb Community

Re: Crossover, L-Pad, Impedence, Resistance question
« Reply #29 on: November 21, 2017, 04:18:04 pm »


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