Hello, I have a subwoofer low pass filter from Aliexpress, like this one:
https://www.aliexpress.us/item/3256802239062806.html
The problem is that it sucks... Even with the lowest cutoff, 500Hz test tones are still very audible, not to mention 250Hz. From ~100Hz it indeed starts getting a bit louder, but I want something that fully cuts off the other frequencies abouve 120Hz because it just muddies the sound.
I use it for a car subwoofer, so it is powered by 12V, but I also power it with 24V when I use it on a DIY 6S battery pack.
Is there any easy "hack" I can do to this low pass to improve it?
If not do you recommend any better alternatives?
Thanks!
https://www.aliexpress.us/item/3256802239062806.html
The problem is that it sucks... Even with the lowest cutoff, 500Hz test tones are still very audible, not to mention 250Hz. From ~100Hz it indeed starts getting a bit louder, but I want something that fully cuts off the other frequencies abouve 120Hz because it just muddies the sound.
I use it for a car subwoofer, so it is powered by 12V, but I also power it with 24V when I use it on a DIY 6S battery pack.
Is there any easy "hack" I can do to this low pass to improve it?
If not do you recommend any better alternatives?
Thanks!
Are the active filter capacitors the blue film ones on the left, or the various surface mount ceramics ??
From the description, I could not get what the electric filter slopes are. It may well be the unit does not suck at all, but your expectations do not match the offering.
If this unit is intended to have a 12db/Octave electric Lowpass transfer function, then the slopes are rather shallow indeed and midrange will leak through.
If this unit is intended to have a 12db/Octave electric Lowpass transfer function, then the slopes are rather shallow indeed and midrange will leak through.
If you need steeper slopes, add passive line level before the amp.
https://www.diyaudio.com/community/threads/whats-on-the-bench-tonight-obt.372508/post-7412387
https://www.diyaudio.com/community/threads/whats-on-the-bench-tonight-obt.372508/post-7412387
Strong words.
Your expectations are unrealistic.
No such a thing as a "brick wall" filter.
Given it has 2 OpAmps per channel, it can certainly handle 12dB/octave, maybe 18dB/octave but then they would brag about it so unlikely.
So 500Hz which is 2 octaves above 120Hz will be attenuated by 24 dB , that in the best case.
Signal attenuated by mere 24dB can VERY WELL be heard.
That said, mids/highs attenuated by 24dB or more will NOT muddy a Subwoofer, by any means.
Even less inside a Car.
You are overthinking it.
Hack?: Just for peace of mind, IF you want extra attenuation, simply cascade 2 of these units, with same setting on both, you'll double attenuation.
Hey, you may even stack 3 of these.
For a mere €4.60 each, I would.
The turnover frequency is variable and the pot controlling this is only a two-gang one, hence 12dB/8ve it is. I agree that 12dB/8ve is a very long way from being brickwall.
There was a thread about these years ago with some pictures of the mods. I downloaded them somewhere....shall have a look
