Some modern, and especially beefy low frequency speakers may tolerate an ommeter, esp w modern DVMs being more sensitive. Older DVMs dish out some good ole battery DC to check ohms, and older, higher freq speakers won't handle that DC. Speakers are meant to handle sine waves. DC is what a speaker sees when an amp goes into clipping, aka, flat lining, being over driven. You may well be ok, in this case, but it is a risky practice to check a speaker with an ohmmeter. That 1 ohm is usually speced as reactance within its given frequency range. A very very few ohmmeters offer this reactance resistance scale. Yours may be a 4 ohm speaker but measure 1 ohm "DC" with a simple ohmmeter. Don't take the risk. Your results in the sine world are not related to dc ohms except as part of a fancy reactance formula.

 

By this description, I shouldn't check any 1 watt resistors either?

 

/
Resistors are almost not reactive [to frequency.] A multimeter has no. Chance if burning one out. A speaker's resistance is in it's inductive reactance... It's cool if wire, which resists AC. The very few wire coil registers have almost non of this, but high frequency circuits are bothered by wire wound resistors. It won't burn them out, quite the opposite. They resist too much. A speaker with thin, light gauge coiled wires, cannot tolerate much dc, and an ohmmeter gives small amounts of pure dc. Old ohmmeters with analog gauges are the worst offenders. Yours is not analog. Your risk is lower. Still, dc ohms and ac/music ohms are two different critters.

 

I've been doing car audio and electronics for years... way back to high school. I've never heard of this.

 

My "way back" can whip your way back, but ignorance abounds. I doubt half the audio techs in any store know. Got old speakers to burn? See how many 8 ohm speakers measure 8 ohms. Use your modern dvm, then an old style. Remember to zero the old ones. Better speakers use lighter weight thinner gauge coils so as to respond to music more faithfully. They are at greater risk. High wattage modern speakers are at less risk. Cheaper old speakers use heavier gauge wire... Less risk.

 

Bill: You could leave a DMM hooked up to that monster for a month! And yes, inductance, reactance, etc. will affect the exact reading, but a resistance reading is good to get you in the ballpark.

As for damaging a driver: (Typical)

DC on a tweeter = smoke (sometimes)

DC on a woofer, intermittent and within reasonable limits (and the amount a Simpson 260 would inflict) = cone movement and no damage.

That's the simple TL;DR.

Source: 50+ years of letting the smoke out of some things and keeping it confined in others.

(Where's a good "What oil weight should I use?" thread when you need one?)

 

I've been measuring voltage, resistance, amps, RMS for years. Never had a DMM ruin a thing. I've used anything from Fluke to Harbor Freight....

EDIT: This got me thinking of all of the DVM's that I own.

1 Fluke (clamp)
1 Snap On
1 Craftsman
1 Extech
2 Klein (clamps)
3 Harbor Freight
1 OEM Tools (Came in a fuel pressure test kit)

 

No VOMs then? Makes you a relative youngster to my old bones. As OL implies, Rules of Thumb can change with the times. Speakers co$t. I err on the side of safety. I'm cheap.

EDIT; Which is why I have to learn a lot of this new fandangled Ford stuff from y'all.

 

I have two. A Sears and a GE. The GE is a mini.

 

Yeah, but did you *build* one?



And my Grandad's Simpson from when he worked for Ohio Power. I'll need the check for a date stamp one of these days on this one.


My Dad has the "M" version (and knowing him, the receipt filed away someplace).