Finding ohm ratings of raw speakers

[Ben Esparza]

I have a few raw drivers that I've acquired over the years. How can I find out the ohm ratings of these misellaneous speakers? Would I use a multmeter? If so, would an 8 ohm speaker read 8 ohms exactly or what might it read?

[crguti]

You can use a multimeter, however it won't read exactly 8 ohms but it'll very close.

[otherclef]

The cheapest meter at radio shack will do the job here. If all you need is Ohms.
8 ohm speaker could read as low 6.X and 16ohms could read as low as 13.X.
In most cases the reading will be less than the stated rating.

[phatbass]

Originally Posted by otherclef

The cheapest meter at radio shack will do the job here. If all you need is Ohms.
8 ohm speaker could read as low 6.X and 16ohms could read as low as 13.X.
In most cases the reading will be less than the stated rating.

IME this ^

[billfitzmaurice]

Originally Posted by otherclef

In most cases the reading will be less than the stated rating.

In all cases the DCR will measure less than the impedance, with Z averaging DCR x 0.7.

[Ben Esparza]

Mine is an Ideal 61-310 Multimeter like the one pictured below. I set it at the 200 setting in the ohms range and 2 the speaker read 5.8. Others speakers that I read that I know are 8 ohms were in the 6.4 +/- a few points. Should I assume the ones in the 5 range are 8 ohm speakers. I jumped 2 of the 6.something ones (parallel wiring) and the reading was half their values...makes sense.

BTW, thanks for the input on Thanksgiving Day.

[Rick Auricchio]

Originally Posted by billfitzmaurice

In all cases the DCR will measure less than the impedance, with Z averaging DCR x 0.7.

Bill, isn't the math backwards here? Wouldn't Z be DCR / 0.7 ? (Which is the same as Z = DCR * 1.42)

Ben, I wouldn't be surprised by a variation in DCR among drivers, so the 5.8 and 6.4 DCR readings are probably both nominal 8-ohm impedance.

[1958Bassman]

Originally Posted by Ben Esparza

Mine is an Ideal 61-310 Multimeter like the one pictured below. I set it at the 200 setting in the ohms range and 2 the speaker read 5.8. Others speakers that I read that I know are 8 ohms were in the 6.4 +/- a few points. Should I assume the ones in the 5 range are 8 ohm speakers. I jumped 2 of the 6.something ones (parallel wiring) and the reading was half their values...makes sense.

BTW, thanks for the input on Thanksgiving Day.

That's just a photo you grabbed from the internet, right?

[Joe Louvar]

Originally Posted by crguti

You can use a multimeter, however it won't read exactly 8 ohms but it'll very close.

+1

[Ben Esparza]

Originally Posted by 1958Bassman

That's just a photo you grabbed from the internet, right?

Right...hence, "like the one pictured below". It's the same model as mine.