High-Pass Filter Help -

[Wardus]

Keep in mind - I don’t know a all what I’m doing: I recently found a pair of speakers. One is big, and handles low really well, and the other seems to do well with highs. I want the big boi to cover all my lows, and the little boi to cover my highs. I saw DIY perks put together some high and low pass filters, but his design was behind a paywall, so I asked GPT 3.5 for some help. I told it I had a 3.9 kohm resistor and a couple 10 uF resistors. It said “

 

Sure! Here's a step-by-step guide to hooking up the high-pass filter for your small speaker:

1. Gather the necessary components: a 10 uF capacitor and a 3.9 kohm resistor.

2. Determine which wire is the positive (+) and negative (-) on your speaker. This is usually indicated by a red or black wire, respectively. If your speaker doesn't have a polarity marking, you can usually determine the polarity by looking at the wiring diagram or the markings on the speaker terminals.

3. Connect the positive (+) wire from your amplifier to one end of the resistor.

4. Connect the other end of the resistor to the positive (+) terminal on the speaker.

5. Connect the negative (-) wire from your amplifier to the negative (-) terminal on the speaker.

6. Connect the 10 uF capacitor in series with the positive (+) wire going to the speaker. This means that one leg of the capacitor should be connected to the positive (+) wire and the other leg should be connected to the positive (+) terminal on the speaker.

That's it! With these connections, the high-pass filter will allow high frequencies to pass through to the small speaker while blocking the low frequencies. You can experiment with different values of capacitors and resistors to fine-tune the crossover point and achieve the best sound quality for your setup.”

 

I don’t know anything about what I’m trying to do, but I just want to verify this. I’ve seen ChatGPT come out confidently wrong before, and I don’t want to burn my house down. Any help would be appreciated. Ask me any questions you need too.

[geo3]

Don't do this at the speaker level where current dominates the signal. If you don't already know crossover design you are going to get massive phase shift and potential cancelation at the crossover point.  The better way is to do this on your interconnects either after your source or after the pre-amp. These signals have almost no current at all. You will need need a 2nd power amplifier, but just get a cheep class-d and stick it on the lower end.

 

Here's what that would look like in a small project box https://www.audiocircle.com/image.php?id=231000

 

Here's a calculator. You don't need a resistor though, just a cap, as your amplifier already has an input impedance. http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

 

[H713]

Just an FYI, crossover design (active or passive) is an enormous rabbit hole. 

 

Generally, for passive crossovers, you're using LC filters, with R mostly being used for minor tweaks - part of impedance compensation networks, notch filters, etc. Inductors and capacitors (ideally) do not dissipate any energy (in the real world this isn't the case, but let's ignore that for the moment), while resistors do. That's okay for things like level matching a tweeter (though you'll still need some pretty hefty resistors in the 10 W range), but you can't get away with that sort of thing in a woofer crossover - the power dissipation becomes ridiculous, and it tends to kill sensitivity. 

 

A few resources:

http://www.zaphaudio.com/ 

www.diyaudio.com

 

 

[Heats with Nvidia]

Get another amplifier and a cheap DSP. Then you can try different crossovers. Everything else is, like H713 already said, going down a deep rabbit hole. Even this will take you quite a lot of time, depending on the sound quality you want.