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Author Topic: qrx112 and 212 12" driver impedence  (Read 2444 times)

jim whitmer

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qrx112 and 212 12" driver impedence
« on: January 26, 2013, 03:46:13 PM »

Pulled a driver from a 112 and it appears to be 4ohms (meters about 5). Is this correct? Specs show bi amp as 8 ohms.

Are the 212's two 8 ohm drivers as the specs show 4ohm biamp?
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Tim Perry

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Re: qrx112 and 212 12" driver impedence
« Reply #1 on: January 26, 2013, 04:08:29 PM »

Pulled a driver from a 112 and it appears to be 4ohms (meters about 5). Is this correct? Specs show bi amp as 8 ohms.

Are the 212's two 8 ohm drivers as the specs show 4ohm biamp?

No, the DC resistance will be less then the nominal impedance. 

Impedance = resistance plus reactance. 


If you measure with an impedance meter, you may measure something near 8 ohms, depending on which frequency you chose to measure with.
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Ivan Beaver

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Re: qrx112 and 212 12" driver impedence
« Reply #2 on: January 26, 2013, 04:16:54 PM »

No, the DC resistance will be less then the nominal impedance. 

Impedance = resistance plus reactance. 


If you measure with an impedance meter, you may measure something near 8 ohms, depending on which frequency you chose to measure with.
And just to add-a normal 8 ohm driver will usually read between 5 and 6.5 ohms on a DC meter.

And the impedance rating is a "general" number-that varies with freq.  At some freq it will be 8 ohms-at others lower and at other higher.  Anything within a "general range" could be considered 8 ohms.

Impedance is one of those "complex' issues.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

jim whitmer

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Re: qrx112 and 212 12" driver impedence
« Reply #3 on: January 26, 2013, 04:56:36 PM »

Don't recall what the mm was set to, but it measured just under 8 on a known 8ohm drive and closer to 5 on the EV.

So, both the 112 and 212 will be loaded with 8ohm drivers?

I have multiple 112 and 212's and was looking to pick up a spare driver, just wanted to know if I needed 4 or 8ohms.
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Tim McCulloch

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Re: qrx112 and 212 12" driver impedence
« Reply #4 on: January 27, 2013, 12:21:37 AM »

Don't recall what the mm was set to, but it measured just under 8 on a known 8ohm drive and closer to 5 on the EV.

Uh... listen to what Ivan is saying
Quote
a normal 8 ohm driver will usually read between 5 and 6.5 ohms on a DC meter

That doesn't mean they all will, and remember that nominal impedance includes the acoustic load of the cabinet or horn.  Free air DC resistance measurements are not de facto measurements of anything other than DC resistance.

An inquiry to EV should bring a definitive answer as to how they load the QRX boxes.
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Re: qrx112 and 212 12" driver impedence
« Reply #4 on: January 27, 2013, 12:21:37 AM »


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