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Old 10-04-2010, 08:32 PM   #1
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Default How to measure ohms with a DMM?

I just got a 15" FI Q sub and am not sure if the its dual 2 ohm or dual 1 ohm voicecoil.
Since is a custom made sub there isnt a stamp on the magnent stating which voice coils it has.
The guy said its a dual 2 ohm sub but then he said it was wired to 2 ohms. Well u cant wire a dual 2 ohm sub to 2 ohms. and yes both voicecoils are being used. lol

so how did i find out with a digital multi meter?
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Old 10-04-2010, 09:18 PM   #2
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I figured it out... Each voice coil measured 2.4 ohms.
Good thats what i needed! Wiring it to 4 ohms and bridging one of my amps to it. just not sure which one
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Old 10-04-2010, 11:18 PM   #3
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Those subs are monsters, they're gonna laugh at that power though.
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Old 10-04-2010, 11:18 PM   #4
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so now you can sell me or trade lol your two 15'*
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Old 10-05-2010, 12:09 AM   #5
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If they were wired in parallel, they would still pull 2 ohms.
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Old 10-05-2010, 12:26 AM   #6
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Quote:
Originally Posted by GXP Venom View Post
If they were wired in parallel, they would still pull 2 ohms.
Who are you talking to and what are you talking about?
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Old 10-05-2010, 04:57 AM   #7
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I traded my 15" JL W0'* for this sub sorry Dude... my buddie said each coil is supposed to measure 1.5 for the dual 2 ohm FI Q.. is that true? did i just measure it wrong?
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Old 10-05-2010, 10:29 AM   #8
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Quote:
Originally Posted by 04MonteLS View Post
Who are you talking to and what are you talking about?
I'm talking to the OP about his question "The guy said its a dual 2 ohm sub but then he said it was wired to 2 ohms"


He'* correct about the 1.5 ohms Raptor. But thats an approximation. To really measure true impedance of a speaker or cabinet requires a rather complex procedure involving a signal generator, power amplifier, and a high frequency AC voltmeter. However, with raw speakers and many cabinets, the ohmmeter function of a digital multimeter can help you identify what the impedance of the speaker should be. Generally, the reading given by an ohmmeter will be about 2/3 to 3/4 of the impedance of the speaker. So, a 4 ohm speaker will typically measure about 2.5 - 3 ohms,a 8 ohm speaker will typically read about 5-6 ohms, while a 16 ohm speaker will measure around 12 ohms. So according to your measurements of 2.4 ohm'*, those are 4 ohm speakers. BTW, Cheap multimeters vary greatly for small voltage or ohmage readings.
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Old 10-05-2010, 07:27 PM   #9
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Thanks LSMONTE.
And Venom u never seize to amaze me with ur broad range of knowledge.
I tried to hook my new system up but when i turned it up all three of my fuses in my amp popped..
I guess my amp just cant push this FI Q
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Old 10-05-2010, 08:56 PM   #10
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Meh, I learned alot of electrical engineering being a contractor of various sorts, been blowing chit up in my cars for almost 40 years, and I hang out at the Custom Shop that did my car alot. I definitely not an audio tech.
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