Simple filters - why can't I just buy one?

[bachatero]

A couple times I've been in the need for a simple filter for something like reducing a room mode and right now to crossover a subwoofer. I also know that such filters can come in formats as simple as an RC for low/high pass and RLC for band pass/reject thanks to my Linear Circuits class. Why is there no product on the market that puts these dead simple filters in a cheap little plastic box with an input and output? In my situations, DSP would be too expensive and fussy and overkill with what's available on the market right now, and passive filters add zero (0) distortion and use zero (0) power.

 

[DonH56]

With all the AVRs and such I would guess there is not enough demand.

Passive filters do have some drawbacks, mainly sensitivity to source and load impedances, and the potential for picking up coupled noise. I would build into a metal box or just metal connector if a low-order filter is good enough.

Closest I've seen for passives: https://hlabs.com/

Marchand makes active and passive crossovers but they are more expensive: https://www.marchandelec.com/xovers.html

You could put that class to work and make your own, of course... (I'm usually too lazy myself.)

HTH - Don

 

[Keith_W]

Behringer CX2310. Yours for less than $100. It's only a crossover though, no PEQ.

And BTW I wouldn't say that passive filters add zero distortion. All of them are minimum phase devices, so they all distort the phase. Whether you can hear it is another matter of debate.

 

[bachatero]

Behringer CX2310. Yours for less than $100. It's only a crossover though, no PEQ.

That looks like a screaming deal, but I don't trust Behringer distortion values with how poor their DACs are. Could this one be better?

And BTW I wouldn't say that passive filters add zero distortion. All of them are minimum phase devices, so they all distort the phase. Whether you can hear it is another matter of debate.

This might be like comb filtering, where phase distortion technically reduces quality but doesn't actually affect most humans.

 

[Keith_W]

The CX2310 is a purely analog product, no digital. So you don't have to worry about the quality of its DAC since it doesn't have one I had one and used it for years (in fact it may still be in storage somewhere!). I can vouch for its reliability. It's made of metal, and all those knobs are stepped. The overall build quality is surprisingly good.

As for distortion, I don't know. It is very likely to be below the limit of audibility. Both phase distortion and THD+N are unlikely to be audible unless present in massive amounts, but if you were to ask me, I would say that you would be more likely to hear phase distortion.

 

[Sokel]

There are lots of them around,here's one:

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

 

[OCA]

A couple times I've been in the need for a simple filter for something like reducing a room mode and right now to crossover a subwoofer. I also know that such filters can come in formats as simple as an RC for low/high pass and RLC for band pass/reject thanks to my Linear Circuits class. Why is there no product on the market that puts these dead simple filters in a cheap little plastic box with an input and output? In my situations, DSP would be too expensive and fussy and overkill with what's available on the market right now, and passive filters add zero (0) distortion and use zero (0) power.

Best DSP (in terms of capabilities) is free (Equalizer APO, Camilla DSP, etc.) if you have a computer as your music source. If you are an analog guy and talking about a Vinly system, then there are preamps with only analog graphic equalizers AFAIK.

 

[wwenze]

Room mode filters are peak filters tho...

Then when you connect the components in real life you start to run into the problem of source and load impedance

There's a reason why DSP is being used to implement these filters.

Also if you want zero practical distortion ie better than using analog components you should be DSP-ing it in the digital realm before the sound has even exited your OS ie use EqualizerAPO