car off, impedence=.9-1.1...car on impedence= -23. wtf

[Wackzirth88 4]

So today i went to replace my girlfriends hifonics bxi 610 with my old rd 1000.1 v1 amp. Before i made the swap she said sub was playing. After i swap the amps i go to tune the amp by ear and absolulately zero output from the sub. So i grab my dmm and turn it to the ohms setting, with the car off it reads .9-1.1 but when i turn the car on it goes to -23-25. first i think maybe the sub has a bad lead or something so i go grab another perfectly working sub and get the same results. Then i was thinking its gotta be the amp then so i switch them back, same results on both subs and both amps. So now shes without beats and its all my fault of course so i wont hear the end of it til i fix it.And to say the least im baffled, you guys got any ideas?

[vic713 1]

LOL, why are you checking the impedence with the car on ? That's your problem right there.

[Kanaworm$ 292]

Are you checking the impedence at the amp or the subwoofer box? You do realize the ohms are going to change when the music is playing?

[Sir-Lancelot 216]

lol

[BanginGMC 23]

The DC resistance is the measurement of the coil at rest. When the cone starts moving, the magnetic field associated with the magnet and the moving coil increases the resistance of the voice coil. Usually the more resonant the enclosure, the higher the impedance rise.

[Kanaworm$ 292]

Here is a great tutorial on the workings of a speaker.... Speaker

[Wackzirth88 4]

I checked the impedence because I wasn't gettin any output from the speaker. I checked the the imp at the amp and box. I also checked the power at the amp, 14.1 volts. The power light was on. When I turned the volume up and turned the gain the sub never moved. The impedence nor power ever changed at the amp either. Lol seriously right this second I thought to myself, rcas. That seems to make sense, I know I had the right on the amps but I don't recall double checking the ones on the hu. Or possibly bad. Now I feel dumb.

[Wackzirth88 4]

I checked the impedence because I wasn't gettin any output from the speaker. I checked the the imp at the amp and box. I also checked the power at the amp, 14.1 volts. The power light was on. When I turned the volume up and turned the gain the sub never moved. The impedence nor power ever changed at the amp either. Lol seriously right this second I thought to myself, rcas. That seems to make sense, I know I had them right on the amps but I don't recall double checking the ones on the hu. Or possibly theyre bad. Now I feel dumb.

[Wackzirth88 4]

I checked the impedence because I wasn't gettin any output from the speaker. I checked the the imp at the amp and box. I also checked the power at the amp, 14.1 volts. The power light was on. When I turned the volume up and turned the gain the sub never moved. The impedence nor power ever changed at the amp either. Lol seriously right this second I thought to myself, rcas. That seems to make sense, I know I had them right on the amps but I don't recall double checking the ones on the hu. Or possibly theyre bad. Now I feel dumb.

[Wackzirth88 4]

I don't even know how that happened sorry about that triple post. That was my attempt at an edit. itouch can be a pain in the ass.

[thehawk93 2]

Don't forget to check your remote wire to the amp.....

[BKOLFO4 29]

The DC resistance is the measurement of the coil at rest. When the cone starts moving, the magnetic field associated with the magnet and the moving coil increases the resistance of the voice coil. Usually the more resonant the enclosure, the higher the impedance rise.

Not quite correct. . .

DC resistance is the resistance with DC current applied. Even if the coil moves, if it is DC current, the resistance is the same (assuming the wire does not heat up and increase the resistance).

Impedance is the resistance when AC current is applied. Because the coil acts like an inductor, the impedance varies with frequency.

Impedance does not just "rise" at all frequencies from the driver being placed in the box. Impedance rise occurs due to impedance changes from different forces on the cone placed in the box. Just like the driver has a free air resonant frequency (and has a spike in the impedance at that frequency), the box will have a resonant frequency. There will also be changes in the impedance at certain frequencies caused by the port tuning, etc. These spikes result in a change to the frequency plot. When playing music, this will normally result in an overall increase in the average impedance the amp sees, since it is not trying to play just one frequency. When burping, you would have to test to determine what the impedance is at the burping frequency - Depending on the sub and the box design, the frequency may be really high, or it could be down near the DC resistance, since the impedance changes with frequency. . .

Brian

[Wackzirth88 4]

Just went and pulled the deck out. I had the rcas plugged in the bus in what is that? Moved it to sub out and it's all good plays just fine. I feel dumb. I deserve to be laughed at.

[Sir-Lancelot 216]

So she needs a new bf not a new sub. Lol. jk bro. Glad you fixed it.

[Wackzirth88 4]

Lol thanks.

[NB50 206]

Future reference, you can not measure resistance/impedance with power applied to the circuit.

[shizzzon 461]

not set to ohms, u cant...

[NB50 206]

not set to ohms, u cant...

enlighten me.