# Help with making crossover modules 4XS



## nsrt4me (Sep 5, 2013)

After posting in another section, this section is much better suited! 
Im using the Audiocontrol 4XS crossover for my current build, and am having trouble figuring out how to make these crossover modules. I have already purchased the 14 pin DIP connectors, and am just having trouble figuring out which resistors to get and to meet my crossover points. 

The audiocontrol site states that I should take the desired crossover frequency and do this:

Resistor value (Kohms) 7200/ frequency

Example: for the desired crossover frequency of 240 Hertz
7200	=	30 Kohms resistor value 240	=	30 Kohms resistor value

The desired crossover points that Im going for to start with are:
Tweeters 5k-20kHz
Midrange 1k-5kHz
midbass 60-1k
sub 35-60hz

Can anyone chime in and state how to calculate the resistors and which ones I would actually need? Im just confused on if I add up the value of each resistor in the module for a total number or count that module as whatever each resistor's value is.


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## Blu (Nov 3, 2008)

Do you have a copy of the Audio Control Tech Notes #2005? It will give you all the info you need.

http://phy6.com/downloads/electronics/Audiocontrol/Tech1005%20PFM.pdf

Hope this helps!

Cheers!


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## ATOMICTECH62 (Jan 24, 2009)

For the front/high to mid you will need (6) 1.5k ohm resistors for 5khz
For the rear/mid to low you will need (6) 7.3k or 71.5k resistors 1k
The rear/2channel PFM will use (6) 121k or 118k for 60hz
The sub (6) 121k or 118k for 60hz
The factory installed 220k mod is set for 33hz.

You wont put a resistor in the middle space so there will be 3 resistors on each end of the header socket.
The values I gave are for commonly found 1% values.You can go +/- 10% on the values if you cant find these.2% and 3% resistors will work also but I wouldn't use 5%.


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## nsrt4me (Sep 5, 2013)

ATOMICTECH62 said:


> For the front/high to mid you will need (6) 1.5k ohm resistors for 5khz
> For the rear/mid to low you will need (6) 7.3k or 71.5k resistors 1k
> The rear/2channel PFM will use (6) 121k or 118k for 60hz
> The sub (6) 121k or 118k for 60hz
> ...


Thank you for the useful info and helping!! Greatly appreciated.


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## ATOMICTECH62 (Jan 24, 2009)

The rear/mid should read 7.3k or 7.1k.Sorry,typo.


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## nsrt4me (Sep 5, 2013)

I cant seem to find resistors with this high of values.


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## ATOMICTECH62 (Jan 24, 2009)

These are very common.Try Digikey,Mouser,MCM,Newark,and Parts express.

Let me check.I might have them.


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## nsrt4me (Sep 5, 2013)

I received my resistors from mouser electronics matching the class posts by ATOMICTECH62 today. Before I install them I wanted to check, the physical size of them are much larger than the small ones tha are installed already. Are these the correct resistors to use?


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## ATOMICTECH62 (Jan 24, 2009)

As long as the ohms are correct they will work but they should have all been the smaller 1/4 watt like the ones on the bottom right.


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