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Topic: Question |
George Frachiseur
From:
Arkansas, USA
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Posted 27 Sep 2018 6:29 pm |
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| Okay I have a stupid question probably but here goes anyway...Is there any way of determining whether a speaker is 4, 8, or 16 ohm voice coil by measuring across the speaker terminals with a ohm meter? |
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Carl Kilmer
From:
East Central, Illinois
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Posted 28 Sep 2018 2:55 am
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Yes, just disconnect the wires before you measure.
It won't usually read a perfect 4, 8 or 16 but it
will be close enough to know which one it is.
_________________
aka "Lucky Kay"--Custom built Rittenberry SD10 3X5, Walker S/S, NV-112, and Hilton Pedal |
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Michael Brebes
From:
Northridge CA
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Posted 28 Sep 2018 6:26 am
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Usually they measure about 25% below the speaker impedance, so an 8 ohm speaker will usually read closer to 6 ohms on a meter.
_________________
Michael Brebes
Instrument/amp/ pickup repair
MSA D10 Classic/Rickenbacher B6/
Dickerson MOTS/Dobro D32 Hawaiian/
Goldtone Paul Beard Reso
Mesa Boogie Studio Pre/Hafler 3000
RP1/MPX100 |
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George Frachiseur
From:
Arkansas, USA
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Posted 28 Sep 2018 9:51 am
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| Thank you guys. |
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Jim Sliff
From:
Lawndale California, USA
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Posted 29 Sep 2018 8:08 pm
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Just to explain a bit - speakers are rated in "impedance" at a specific frequency. Actual impedance changes as frequencies they reproduce change.
They are "measured" in DC resistance, which is constant in a conventional speaker. The DC resistance, rounded up, became the standard method for measuring/identifying impedance decades ago.
FWIW "impedance" is not the only specification important when selecting a speaker. "Power handling" - in VERY general terms, the maximum power a speaker's voice coil can handle without blowing the speaker, is just as important. There are other specifications a swell, but they apply more to comparative loudness and amp voicing.
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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ajm
From:
Los Angeles
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Posted 30 Sep 2018 7:59 am
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Impedance is resistance of an item to an AC signal at some frequency.
Impedance (AC resistance) is measured in ohms.
Impedance of an item at a signal of frequency = 0 Hz (DC) is commonly referred to as resistance (or DC resistance).
Therefore, "resistance" is also "Impedance" measured in ohms at a frequency. It just happens that in this case the frequency is DC, and DC is equal to zero Hz.
When you measure the resistance of something using a digital multimeter you are measuring the resistance/impedance at 0 Hz.
(There are some meters, usually more expensive, that have a setting for measuring impedance, but we'll leave those out for now.)
The impedance of a speaker is usually spec'ed or measured at some specified frequency that is not DC.
To answer what the OP asked: What Michael Brebes said. |
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Greg Cutshaw
From:
Corry, PA, USA
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