How to measure impedance amp is seeing from sub with DMM

[USAFradartech 10+ year member]

The title says it all. Is there a way to do this? I have a True RMS multimeter on hand

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[neo_styles 10+ year member]

This is stickied in the Help 101 tab at the top of the forum. You know Ohm's Law?

 

[Julian 10+ year member]

No not while it's playing... you can measure DCR of the subs. Unless you're burping there is no reason to find out because impedance curve will be different based on the frequency being played.

 

[dragnix 5,000+ posts]

Just put ur dmm to the sub n get an idea of "baseline" resistance

 

[USAFradartech 10+ year member]

This is stickied in the Help 101 tab at the top of the forum. You know Ohm's Law?

Ok i will check that out. Thanks!

 

[vector 10+ year member]

Just measuring the impedance of the speaker will usually give you a good idea.

Are you wanting to know worst case scenario? Sometimes for fun I will use Winisd (LinearTeam) to model the speaker and box that I have. I take the lowest point in the models impedance curve and play that frequency through my system while clamping (

) the amplifier. With this result you can calculate out the lowest actual impedance your amp should see at any frequency.

 

[keep_hope_alive Premium Member]

measuring impedance curves is what the DATS or WT-3 is for.

Dayton Audio DATS Dayton Audio Test System 390-806

using Ohms law to measure impedance requires you know two of the four parameters + know what frequency you are playing. Voltage is easy and a given. Current is the next option, and fine for low volume testing.