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voice coil impedance

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=39784
Printed Date: August 18, 2022 at 6:04 AM


Topic: voice coil impedance

Posted By: thepyrofish
Subject: voice coil impedance
Date Posted: September 26, 2004 at 5:07 PM

I recently installed a sub in my car that I was told was a dual 2-Ohm speaker, but when it didn't meet up to expectations I decided to check the resistance with a multimeter to be sure.  i got 5.1 ohms on one coil and 5.2 or 3 on the other.  I know the impedance that is measured on a DMM is not exactly the rated one, but what would this speaker be if they measure that high, I was thinking dual 4 but I was expecting a reading of closer to 4 for that, is my sub damaged?

It is a soundstream DV-12 , by the way,

any ideas?




Replies:

Posted By: stevdart
Date Posted: September 26, 2004 at 7:01 PM
Yes, a dual 4 ohm sub.  You're possibility of wiring would be parallel for a 2 ohm load, if you have a mono amp.  I would guess, though, that you are bridging a stereo amp?  And ended up with a 8 ohm load with coils in series?

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: thepyrofish
Date Posted: September 26, 2004 at 9:03 PM

exactly, i thought it was a two ohm and wired it exacty how you said, so it ended up being 8

thanks for your help





Posted By: DYohn
Date Posted: September 27, 2004 at 8:18 AM
thepyrofish, please type your posts directly in the web window, don't cut and paste from another application.  This will help avoid the confusing result seen above with all your HTML formatting code visible.

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Posted By: thepyrofish
Date Posted: September 27, 2004 at 8:54 AM
sorry about that, I was typing directly into the browser but I was at a friends house and his computer ain't quite right.




Posted By: haemphyst
Date Posted: September 27, 2004 at 12:48 PM
ummm, I think that a 5.2 ohm (DC) driver would be closer to a real world 8 ohm impedance... a DCR will NEVER be higher than a reactive impedance. If you wired those voice coils in series, you would have a 16 ohm load presented to the amp. You need to parallel the voice coils for a 4 ohm load, then either run it that way to a mono amp, or bridge a stereo amp to get two ohms per channel, a (usually) safe load for most amplifiers of today.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: stevdart
Date Posted: September 27, 2004 at 8:09 PM
FYI, one of the posts was deleted.  In it thepyrofish said that he checked internal resistance of the DMM by touching probes together and got a 1.5 (if I remember exactly) reading, so he deducted the 1.5 from the reading of 5.2 and arrived at 3.7 ohms, with which I have agreed seemed usual for a 4 ohm driver.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.





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