Tweeter Impedance

[moe3152]

Can anyone tell me if a capacitor on a tweeter affects it's impedance? Without any music playing the capacitor does not have continuity, so a multimeter has nothing to read.

Click to read more...

 

[1aespinoza 10+ year member]

Can anyone tell me if a capacitor on a tweeter affects it's impedance? Without any music playing the capacitor does not have continuity, so a multimeter has nothing to read.

No. The tweeter has the same impedance regardless. The amplifier/radio will still see 4 Ohms.

 

[moe3152]

No. The tweeter has the same impedance regardless. The amplifier/radio will still see 4 Ohms.

OK thanks!

 

[Jimi77 5,000+ posts]

Can anyone tell me if a capacitor on a tweeter affects it's impedance? Without any music playing the capacitor does not have continuity, so a multimeter has nothing to read.

Capacitors are reactive so at some frequencies they present no impedance, while at lower frequencies the impedance of the capacitor will increase.

 

[moe3152]

So, that being the case, if it's wired in parallel with the woofer then the total impedance for the two can be all over the chart and a multimeter can't really tell you anything, right?

 

[Jimi77 5,000+ posts]

So, that being the case, if it's wired in parallel with the woofer then the total impedance for the two can be all over the chart and a multimeter can't really tell you anything, right?

Kinda. We know the woofer's coil's impedance rises at higher frequency and the capacitor that's inline with the tweeter has the opposite effect. Whatever the woofer's impedance is, is what you should consider the impedance of your circuit.

 

[moe3152]

Ok thanks. I did bypass the cap with a small jumper wire and measured the combined impedance of the tweeter and woofer(parallel) and it dropped to 4 ohms.

 

[Jimi77 5,000+ posts]

Ok thanks. I did bypass the cap with a small jumper wire and measured the combined impedance of the tweeter and woofer(parallel) and it dropped to 4 ohms.

Doesn't matter. You measured DC resistance. Impedance is reactive and changes with the frequencies(s) being played.

 

[moe3152]

Doesn't matter. You measured DC resistance. Impedance is reactive and changes with the frequencies(s) being played.

I see.

 

[YusufGi]

No. The tweeter has the same impedance regardless. The amplifier/radio will still see 4 Ohms.

 

[HardofWhoring]

Why do you have a cap on a tweeter?

 

[1aespinoza 10+ year member]

Why do you have a cap on a tweeter?

It filters out the lower frequencies.

 

[HardofWhoring]

It filters out the lower frequencies.

A capacitor is basically a battery. How would it do that?

 

[Jimi77 5,000+ posts]

A capacitor is basically a battery. How would it do that?

Because that is what a capacitor does. When wired in series a cap functions as a high pass filter. Wired in parallel, caps are low pass filters. Music isn't an DC power source, it's AC, therefore the capacitor is charging and discharging as the music plays. When wired in series, at lower frequencies the cap will be able to charge/discharge fast enough to prevent a change in voltage and therefore block those frequencies. Capacitors are common in power supplies to block noise; that is why you don't see/hear 60hz background noise in your home electronics. Capacitors are also common in crossovers to block frequencies.

How does a capacitor blocks low frequency signal? Please explain it without the impedance formula?

I know that a capacitor blocks DC because at some point of time it gets charged to the applied voltage. The charge which is accumulated on the plates provide an opposite electric field to that pro...

electronics.stackexchange.com

 

[1aespinoza 10+ year member]

block

Hot damn that was an awesome read! Thanks for the link.