testing coils with a dmm...

[iceteebone 5,000+ posts]

isn't therea way to check the resistance of the coil with a dmm? i just got some rl-p's and on my dmm there are numerous setting for resistance. i turned all the way to the right, in the ohm section and put the leads to the sub terminals and got 3.3 ohms. does this sound right? it also made a weird noise, the dmm not the sub.

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[audioholic 5,000+ posts]

The settings on a DMM for testing ohms is simply a range. You just want to set it to as close to a range as you can. For example, if you are measuring something you expect to be in the 3-4ohm area, you would not want a scale of 1-1000ohms. Setting the scale to 1-10ohms would make reading 3.3ohms much easier. (edit: this is only for analog style multi-meters actually)

3.3ohms sounds about right for a nominal 4ohm sub.

DMM's sometimes have their own internal speaker for an audible interface setup. Perhaps this is what you heard?

 

[iceteebone 5,000+ posts]

The settings on a DMM for testing ohms is simply a range. You just want to set it to as close to a range as you can. For example, if you are measuring something you expect to be in the 3-4ohm area, you would not want a scale of 1-1000ohms. Setting the scale to 1-10ohms would make reading 3.3ohms much easier.
3.3ohms sounds about right for a nominal 4ohm sub.

DMM's sometimes have their own internal speaker for an audible interface setup. Perhaps this is what you heard?

ok i just wanted to make sure i was on the right setting. is there anyway to tell if a sub is blown or not without actually feeding it power?

 

[squeak9798 5,000+ posts]

ok i just wanted to make sure i was on the right setting. is there anyway to tell if a sub is blown or not without actually feeding it power?

If the coils read fine, then they aren't fried.

Gently pressing the cone should give you an indication if they are mechanically damaged or not.

If they don't appear mechanically damaged, and the coils read fine....then generally the sub is in good shape.

 

[Shyne151 10+ year member]

ok i just wanted to make sure i was on the right setting. is there anyway to tell if a sub is blown or not without actually feeding it power?

If you get some crazy number as a reading for the voicecoil it is more than likely blown... like if u get 9 for a 4ohm voicecoil. Anything within an ohm is usually alright.

 

[Chevyaudio 5,000+ posts]

3.3 sounds good for 4 ohms, the coils i have tested are rarely exactly right.

 

[iceteebone 5,000+ posts]

If the coils read fine, then they aren't fried.
Gently pressing the cone should give you an indication if they are mechanically damaged or not.

If they don't appear mechanically damaged, and the coils read fine....then generally the sub is in good shape.

ok the subs seems to be in good condition then //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[btnhfan 5,000+ posts]

Also, if you can zero the ohm reading on your dmm, if its a good one, do that first.