# Is this right?

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#### CryingDragon

in short i'm looking for the pot [var resistor] to adjust the frequency of this crossover

#### Attachments

• xo.jpg
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#### peranders

Paid Member
You must have a resistor first also. You must have equal amount of R and C's.

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#### CryingDragon

so if i put a resistor in the line in it'll work?

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#### CryingDragon

Or will this work?

Do i have to put a cap where "question one" is and a resistor where "question 2" is to make it work?

Witch one would function better?

#### Attachments

• xo.jpg
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#### audioPT

Hi!!

Use like the schematic I send:

In this way, you can vary the xover frequency.
It is to be used in a subwoofer system?

Regards.

Pedro Martins

#### Attachments

• varxover.gif
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#### peranders

Paid Member
I'm sorry but you are totally of track now. I'm afraid you must study the subject more. Good reading can you find here.

http://www.national.com/apnotes/apnotes_all_1.html

AN-307, 31, 72, 712, 20, 31, 227, 346, 48, 32, 64
LB-5, 11

Try these links or some of them for starters.

Active filters can be really complicated (I have a fat book in the subject) but you can take shortcuts but reading the application notes.

#### peranders

Paid Member
Pedro has the right circuit (I you want 12 dB/octave), notice that the ganged potentiometer must be conntected so the resistor value are equal all the time. If you choose this kind the caps must have unequal values.

I recommend though that you try to pick up some information from National. Their application notes are very good.

#### carlmart

Peranders

"Pedro has the right circuit (I you want 12 dB/octave), notice that the ganged potentiometer must be conntected so the resistor value are equal all the time. If you choose this kind the caps must have unequal values."

Perhaps it's a bit difficult having the same resistor value all the time on both pots, so a multiposition switch should be used. On the other hand most volume pots we use on our preamps do not seem to image off center when we move them, so maybe they are suitable after all.

How do you adjust those unequal value caps?

Carlos

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#### CryingDragon

Thanks pedro i'll try it.

#### SilentWolf

Just umm... testing to see if this works... so umm... yeah
ILU CD

#### NU_NRG

CryingDragon
where do you intend to use this filter?

SilentWolf

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#### CryingDragon

Silent is my fiance` Ummm I was gonna use it as active high and low pass in a bi amp system.

#### audioPT

Hi!!!

I've been in holidays!
Nice!!

Well, Only today I've seen this thread.
Crying Dragon, I think is simple if you check my friendRod Elliot's site and check his crossovers as the little programs he has.
I think he has all you want.
Yes, I know, I also have a site but not fininhed yet!

But... if you can't achieve any ansewr to your questios in Rod's site, check the RANE site.

Big Regards

Pedro Martins

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