analog EQ

[julitoole]

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.

 

[voodooless]

One of the cheapest solutions is probably this:

the t.racks DSP 4x4 Mini

Compacte 4-kanaals DSP Ingangen: 4x 6,3 mm gebalanceerde Jack, Uitgangen: 4x 6,3 mm gebalanceerde Jack, Programmering via USB (Windows), Stroomvoorziening via externe 12 V DC netvoeding (plus binnen), Gewicht: 0,6 kg, Afmetingen: 160 x 150 x 40 mm,...

www.thomann.de

Or, if you want to tinker a bit more:

*The Big Winter Deals* WONDOM OFFICIAL SHOP - Amplifier Board - Sure Electronics - ADAU1701 - 18650 charger - Sigmastudio

Sure Electronics is a professional audio amplifier supplier that provides electronics hobbyists and business partners the middleware which can help reduce customers' development difficulties and save their precious time-to-market by making the products directly released in the market.

store.sure-electronics.com

 

[Clmrt]

Rolls SX21 Tiny Two-Way Crossover w/Level Controls

Rolls SX21 Tiny Two-Way Crossover w/Level ControlsThe SX21 has 1/4" input, low and high output jacks, as well as input, crossover frequency, low and high output controls. It is powered by an included AC/DC adapter, and designed to be uncomplicated and effective for years to come. AC power...

www.parts-express.com

 

[DVDdoug]

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.

 

[julitoole]

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?

 

[olieb]

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€

TINYSINE TSA1701 DSP Module ADAU1701 Sigma Studio - Audiophonics

The TinySine TSA1701 is a complete digital audio signal processing module. The main chip used is an ADAU1701, allowing this DSP to be used as well for active speakers or to create an efficient 2.1 system.

www.audiophonics.fr

This is 23€ and 4 channel, but it is without case and to program it you need an interface, that is 24€ on top.

TINYSINE USBI JTAG DSP Sigma DSP Programmer - Audiophonics

The USBi JTAG from TinySine is a USB programmer for DSP Sigma. It can be used to program chips using SigmaDSP signal processing technology. It is possible to use this programmer with the ADI SigmaStudio software.

www.audiophonics.fr

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.

TPA3116 Audio Module 2.1 Subwoofer HiFi Bluetooth Digital Power Amplifier Board | eBay

Nano Sheild. 1, amplifier board use current sound, noise?. OLED LED&RGB. 4, the amplifier will burn out. B, poor quality of the input signal; the output of the device connected to the input playback is not normal noise is caused by the abnormal input of the audio source.

www.ebay.com

 

[julitoole]

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.

 

[Sokel]

Yep.here:

Cheap analog electronic crossover

I've been playing lately with a very cheap analog 2-in/4-out analog crossover. Is somehow DIY but very easy to fix. To my surprise it measures very decently! (note that has been measured with the worst possible conditions,long cables soldered just to see,adapters,noisy PSU and by someone totally...

www.audiosciencereview.com

You'll find more info at the thread as well at the links.
You'll also find how to build it for dead cheap.

 

[Sokel]

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.

M-SUB6 Active Subwoofer LowPass Filter Freq. 50Hz~250Hz+Bass Boost+Phase Control - Motronix

M-SUB6 High Quality Professional Active Subwoofer Low Pass Filter Crossover Preamp. Variable Low Pass Frequency Control 50Hz~250Hz Input Volume Bass Boost +12db @ 45Hz (Switch control) Phase Shift: 0/180 (Switch control) Assembled Board Ready to use!!! High quality Product and reliability PCB...

motronix.co.il

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) :

MPS-DV2S/DV1S 110/230Vac to Dual Regulated 12-18Vdc (+ 0 -) Power Supply for Audio Pre Amplifiers - Motronix

MPS-DV2S / DV1S Power Supply for Audio Pre Amplifiers ***On board 2 Molex standard connectors for all Motronix products*** 115/230Vac 50/60Hz Input Dual Regulated 12/15/18Vdc +12V 0 -12V 2x200mA +15V 0 -15V 2x160mA +18V 0 -18V 2x100mA Compact Size Board Product For Audio Applications Double...

motronix.co.il

or switching one for 15 euro:

Mean Well PD-2515

Mean Well PD-2515 AC-DC Dual output Open frame Power supply; Output 15Vdc at 1A -15Vdc at 1A

www.meanwell-web.com

,some connectors,etc and you're good to go.

 

[Sokel]

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.

 

[voodooless]

Sigma ADAU1701 Review (DSP Board)

This is a review and detailed measurements of the Sigma ADAU1701-2In4Out DSP board from @3eaudio . It was kindly loaned to me by a local member. I think it costs $18 for the main board (?) The version I have has the tone control and USB interface options as well. This is what the whole setup...

www.audiosciencereview.com

This is also a cheap option, though to program it, you’ll need an adapter board, which costs about as much.

 

[julitoole]

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?

 

[Sokel]

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?

Here's the documentation:

https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/PD-25/PD-25-spec.pdf

The ground ones are the "COM" (two middle ones) .
Positive one is Pin1 and Negative one is Pin 4.

 

[julitoole]

SO basically like I collor4 coded the pictures here yes?
of course the signals have to be connected but the power is right ?

 

[julitoole]

dang one of the blue coded pins on the crossover chip was supposed to be green.
depening on which is + or -

 

[julitoole]

And of course connect the orange one to a reasonable volume of conducting metal

 

[julitoole]

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

 

[Sokel]

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:

https://www.aliexpress.com/item/32970977095.html

(make sure you buy screws too,or ask the x-over shop to send you if they have some)

 

[julitoole]

This was so helpfull thanks!

 

[julitoole]

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?