Looking to filter out low frequencies

[Frenchy906]

Hello, I've tried searching, and I've found the calculation on how to figure out what size capacitor I need to filter out frequencies. I'm looking to filter out frequencies lower than 600hz on a set of 4ohm 4x6 speakers I have installed in my 2001 S10.

However, the result I am getting is:

6.634819E-05

What size capacitor does this refer to?

Also, I'm only pushing about 18W RMS to the speakers, they are hooked up to the head unit.

Thanks for any help.

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[Full Tilt 10+ year member]

Maybe I'm confused, but aren't you looking for some sort of band/high pass filter?

 

[Frenchy906]

Maybe I'm confused, but aren't you looking for some sort of band/high pass filter?

Yes, I do believe so. But rather than spending the $10 on those Bass Blocker thingamajigs, which are no more than an in-line resistor and wire, I figured I'd make my own from resistors I can buy at my local RadioShack.

 

[Full Tilt 10+ year member]

Yes, I do believe so. But rather than spending the $10 on those Bass Blocker thingamajigs, which are no more than an in-line resistor and wire, I figured I'd make my own from resistors I can buy at my local RadioShack.

You plan on making your own filter? Most aftermarket stereos have a lot of those filters built in, if you'd like to go that route.

 

[Jepalan]

The result I am getting is:

6.634819E-05

What size capacitor does this refer to?

A 66.25uF (microfarad) capacitor will block frequencies below 600Hz on a 4 ohm speaker.

This will create a 6dB/octave (first-order) HIGH-pass filter effect with the 3dB corner at 600Hz.

There is a good chart here: Car Audio - Speaker Crossover Chart and Capacitance vs. Frequency Calculator(High-pass)

And here: http://www.bcae1.com/passxovr.htm

Use a non-polarized electrolytic capacitor of proper voltage rating (100 volts is a good choice for car audio)

(sorry, I meant high-pass, not low-pass. fixed in above paragraph)

 

[Frenchy906]

You plan on making your own filter? Most aftermarket stereos have a lot of those filters built in, if you'd like to go that route.

My radio does have high pass filter on it.

However, I've got a set of small 4x6" speakers in the dash of my s10 I just picked up, that I don't want hardly any bass frequencies going to. Therefore, the reasoning behind wanting a 600hz high pass on those speakers.

 

[Frenchy906]

A 66.25uF (microfarad) capacitor will block frequencies below 600Hz on a 4 ohm speaker.This will create a 6dB/octave (first-order) HIGH-pass filter effect with the 3dB corner at 600Hz.

There is a good chart here: Car Audio - Speaker Crossover Chart and Capacitance vs. Frequency Calculator(High-pass)

And here: Passive Crossovers

Use a non-polarized electrolytic capacitor of proper voltage rating (100 volts is a good choice for car audio)

(sorry, I meant high-pass, not low-pass. fixed in above paragraph)

If I can't find a 66.25uF, can I run multiple capacitors together? I'm kind of new to this external crossover type stuff. And if so, would I just solder the two capacitors together? Or would I run one on each terminal of the speaker?

Please help.

Thanks,

 

[Frenchy906]

47µf 35V 20% Axial-Lead Electrolytic Capacitor | RadioShack.com

These would give me a cutoff of over 800Hz, which I suppose for dash speakers probably wouldn't be terrible.

Would these be the right capacitors?

 

[maylar 10+ year member]

47µf 35V 20% Axial-Lead Electrolytic Capacitor | RadioShack.com
These would give me a cutoff of over 800Hz, which I suppose for dash speakers probably wouldn't be terrible.

Would these be the right capacitors?

No. Those are polarized (DC) capacitors. For audio we want non-polarized (AC). Radio Shack doesn't have any close to the values you want.

66 uF isn't a standard value, however 33 uF is. You can put two 33uF in parallel to give you 66 uF.

33uF 100V Non-Polarized Capacitor | 027-350

 

[BoomTaco64]

best bet is to just buy the cheap bass blockers. cutting off at 600hz will not sound that good. i would look to cutoff at about 100-200 for better overall sound.

only 10 bucks:

Bass Blockers (300 Hz cut-off) Pairs at Crutchfield.com

or these:

Bass Blockers (150 Hz cut-off) Pairs at Crutchfield.com