Subs acting strange

[qtipextra 5,000+ posts]

Today, when a sine sweep of 10-60hz was randomly picked, I looked back and something seemed a bit weird looking at the subs, but I was driving so I didn't have a chance to really observe what seemed different. When I got a chance, I pulled off the side of the road and watched what happened. It kinda seemed like one was moving more then the other. I didn't have my DMM so I couldn't check the coils then. I couldn't really tell what was wrong, so I just drove the rest of the way home.

Then I got my DMM and checked total resistance. It read .7 ohms (Subs are wired to a 1 ohm load). Then I hopped into my car and played a 23hz tone at a lower level, and slowly increased it to see if I could see anything happening. One of the subs didn't move as much. I got out of the car to look at a side angle, and I could definitely tell that the one didn't move as much. It actually looked like it was being pulled back a little bit, as if there was a slight negative DC voltage on the coil.

So I pulled out the sub and checked individual coils (Each coil is 4 ohms). Each coil read about 3.8 ohms. And now, being puzzled, I ask you for suggestions.

Thanks

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[billabongcr 5,000+ posts]

you got me.

 

[djman37 5,000+ posts]

smoking too much?//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

pics of box? any chance 1 sub is unloading in a ported box?

 

[qtipextra 5,000+ posts]

Looking at that picture, the sub that isn't moving as much would be the sub to the right.

It might just be to the fact that the tone is 10hz or more lower then tuning.

I've had the subs for a year and a half. I don't know if it's always been like this at such a low frequency (I hardly ever play anything lower then 28hz), and I just never paid attention, or if it just started. I also don't know if it does this at higher frequencies.

 

[djman37 5,000+ posts]

i think you're right on unloading below tuning. The sub on the left is unloading quicker.

 

[qtipextra 5,000+ posts]

I will go and put the sub back in, and check it out, play a 35hz tone or so, then update.

 

[qtipextra 5,000+ posts]

Update: Everything seems to be fine above 28hz. I just never noticed it doing this before. Thanks for the suggestions.