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analog EQ

julitoole

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boiled down question: is there a cheap device with line level input that puts out line level but only below a certain frequency? (eg crossover setting on a sub)

so in my kitchen I want to set up a rather non hifi system just for fun when cooking with friends,
I got 2 cheap active subwoofers and 2 passive speakers but plan on replacing the amp parts in the subwoofers as they make weird noises and seems to be electrical unsound, with an external amp basically making the subwoofers passive.


Now I need a way to "extract" the sub frequencies so to speak imitate the crossover setting that an active sub usually has.

I did find amps that have such a thing installed allready but didnt find anything "cheap" that seems suitable and I would rather have such a device as a standalone to be more flexible with my other gear and maybe have soemthing that does not degrade the signal significantly.


I dont know if thats the right word but it seems to be that I need a basic analog equalizer.

If somebody has a different idea on how to pair them in a reasonable way please tell.
 
One of the cheapest solutions is probably this:


Or, if you want to tinker a bit more:

 
 
You can get active crossovers for around $100 USD and you don't have to connect the high-pass section.

You can get graphic equalizers starting at about the same price. An equalizer only cuts (or boosts) 12 or 15dB, whereas a crossover/filter slopes-off continuously. But in this application the sub is going to attenuate the higher frequencies "naturally" anyway and it would probably be OK.
 
thanks for giving me some options. all of these would solve the issue.
But I was looking for something that costs way less. would say at most 60€
To be fair I dont think I would get the wondom thing to work, would need very fitting documentation, but it seems like this would be in the price range.
As there are very cheap devices that have something like that included I thought there maybe is a cheap way to do it, all of the proposed solutions are as far as I see it digital (please correct me if I am wrong) isnt there a analog devicethat does what I ask? I really would just need 1 Low pass filter, and 12 or 15 dB attentuation I think would suffice.
How does it work in the subwoofers that have such a setting? does every such sub do an analog to digital conversion then does a dsp and then converts it back to analog?
 
thanks for giving me some options. all of these would solve the issue.
But I was looking for something that costs way less. would say at most 60€
This is 23€ and 4 channel, but it is without case and to program it you need an interface, that is 24€ on top.
There are versions with integrated (4ch) amps too.

And these are digital of course. I am sure a second order lowpass with some adjustment can be built cheaply in analog, but I do not know of such a device and it would be limited in many ways (delay? high pass?...)

EDT: You can get an analog 2.1 crossover and power amps on top for 20€ too. From China of course.
 
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hmm this seems very achivable.
Would not mind fiddeling around as long as there is proper documenation on how to do it so if somebody has knowledge how to do this analog pls tell.
but if nobody has I guess I will try this one.
Would really prefer analog as I dont need anything besides that low pass filter right now.
 
Yep.here:

You'll find more info at the thread as well at the links.
You'll also find how to build it for dead cheap.
 
I see they also have a low pass only version with variable Low Pass,Bass Boost +12db @ 45Hz and Phase Shift (0/180° ) for 16 euro or so.


add a 30 euro PSU to it (you can also find dead cheap ones at ali and the shorts but I wouldn't shop from there) :

or switching one for 15 euro:

,some connectors,etc and you're good to go.
 
this seems like exactly what I looked for. Thanks!
Is there a benefit or drawback to use a psu or a switching one?
like less noise? longer life expectancy?
And I would just take a power cord that has grounding cut it open fiddle the 3 cords to the psu?
that seems clear but both psu have 2 sets of + - ground but on the active subwoofer pcb I only see one set of + - ground how would I connect them?
For your application no benefit,just get the meanwell,they are really good.
The two grounds you see is for convenience,just tie them together and you're ready.

Be VERY careful with the mains,as you do with anything else.Best thing you can do is find a metal box (like from cookies or a little sturdier ) bolt everything inside with metal standers so the PCB's don;t touch it,strip your mains cord,connect Live and Neutral to the PSU and Ground to the box.
Here for help for everything along the way.
 

This is also a cheap option, though to program it, you’ll need an adapter board, which costs about as much.
 
thanks a lot again
sry for deleting the post but I had a lot of things the wrong way around.
but I think I got it now. do you know which of the 4 pins on the meanwell are the ground ones ?
or will it be written on the pcb?
 
SO basically like I collor4 coded the pictures here yes?
of course the signals have to be connected but the power is right ?



Screenshot 2025-01-28 204120.png
Screenshot 2025-01-28 204053.png
Screenshot 2025-01-28 203934.png
 
dang one of the blue coded pins on the crossover chip was supposed to be green.
depening on which is + or -
 
And of course connect the orange one to a reasonable volume of conducting metal
 
I use Rca for signal would I connect the ground on the signal in side of the crossover chip to the orange grounding?
a

Edit: ahh its for stereo to mono got it
 
Yes,it seems ok.
The pcb will be grounding itself by its standers,you only make sure you bolt the mains cord ground to the metal case.
You can use such as these:


(make sure you buy screws too,or ask the x-over shop to send you if they have some)
 
hmm I m trying to find suitable cables for this do they have a special name? molex cables doesnt seem to give me the right results.
Edit: or these jumper wires?
 

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