Dual Car Subwoofer

[shweat69]

Hi Guys,
new to this site and need help sorting out an issue I am having.
I recently purchased a Dual Clarion 12 subwoofer with terminals on both sides of the box. I connected both subs (matching positives and negatives) , it appears that I have a mono amp as I only have one set of speaker wires coming out from amp. I connected these to one side and although both subs are working however one of them is making a farting type noise at any level. I have pulled the speaker out to have a look for cracks or something in the box and all is gone from that perspective. If I was to put my hand on that speaker making this noise it stops. At first I thought maybe its being overloaded but if that was the case both speakers should be making this noise.
I am pulling what little hair I have left out! trying to work out this issue.
please can anyone help.
thanks in advance.

 

[giantpandaman2]

youtube is your friend.

https://www.youtube.com/watch?v=PQ3CQE_NB0c

 

[Harvey]

You didn't mention the model number of your subwoofer, but if I understand correctly, the box contains two separate woofers, each with its own pair of terminals. If so, and you connected the one sub amp to only one of the woofers, the undriven woofer would move in sympathy with the driven woofer and could produce the farting effect you note.

Short of buying a second amp, the solution would be to drive both woofers with the one amplifier.

1. Check the specs to know the impedence of each driver. Typically, it will be 4 or 8 ohms, but some are rated as low as 2 ohms to get more power at lower voltages.

2. Check the specs for your sub amp to determine the minimum impedence it is rated to drive. Driving a load higher than its minimum will not damage a solid state amplifier. The amp will just deliver less power. Driving an impedence lower than its minimum rating is like a partial short circuit which can raise distortion and possibly damage the amplifier.

3. Determine the optimum configuration for your amp and woofers, and connect the amplifier to both woofers.

Math time...

To connect two identical woofers in parallel, connect the positive lead from the amplifier to the positive terminal of BOTH woofers and the negative lead from the amplifier to the terminal of BOTH woofers.

The impedence of two identical woofers connected in parallel is half the impedence of either woofer. For example:

Two 4 ohm woofers in parallel = 2 ohms.
Two 8 ohm woofers in parallel = 4 ohms.

To connect two identical woofers in series, connect the positive lead from the amplifier to the positive terminal of ONE woofer, connect the negative lead from that woofer to the positive terminal of the other woofer, and the negative terminal of the amplifier to the negative terminal of the second woofer.

The impedence of the same woofers in series is twice the impedence of either woofer. For example:

Two 4 ohm woofers in series = 8 ohms
Two 8 ohm woofers in series = 16 ohms

Choose a configuration where the combined impedence is equal to, or greater than, the minimum rated imepdence load for the amplifier. Do NOT try to connect two 4 ohm woofers in parallel if your amp is not rated to drive a 2 ohm load. It could blow up your amp.

Hope that helps.

 

[Paul98]

What model subs, and amp are they.

 

[shweat69]

Hi Guys,
thank you all so much for your advice. I have double checked and currently have them wired in parallel and are working fine. Unfortunately I tested the sub making the farting type noise and it appears to be a problem with the driver itself, though I cant find any tears or cracks so I am a little baffled.
the Subs (which I should have mentioned) are dual V.C 12 inch Clarions.

 

[master_shake_]

is the voice coil separated from the basket?

you're gonna have to pull it out to check.