Measuring impedance with multimeter

So is there no instrument that can be acquired without breaking the bank for nonEE to broadly measure impedance, or in this hobby where snake oils are rampant does everyone blindly except vendor claims?

You need a sine wave generator and probably a 100 ohm potentiometer in addition to your meter.


The sine wave generator drives the speaker, which is wired in series with the potentiometer; the latter only uses the center lead and one other lead.

Set the meter to AC volts.


You adjust the pot so that your meter reads the same voltage across the speaker terminals as the across the pot. Then remove the pot from the circuit and measure the DC resistance- that is the impedance of the speaker at that frequency.


So you need to do this a bunch of times but with a bit of graph paper you can draw up the impedance curve.

You can measure speaker impedance using Room EQ Wizard and a home made harness.


https://www.roomeqwizard.com/help/help_en-GB/html/impedancemeasurement.html


I personally recommend DATS V2 as a complete, out of the box solution:

http://www.daytonaudio.com/index.php/dats-dayton-audio-test-system.html
Around $99 at Parts Express

As said above, the 'resistance' that you measure with your ohm meter is in DC, i.e. direct current. Impedance is an entirely different measurement that uses an alternating current (The music signal happens to be just that, AC). It might like understanding the horsepower of a car. The stated horsepower isn't exactly what you will be experiencing in driving, at least considering differing speeds, roads, driving habits, etc. It gives a baseline for you to consider. 

If its the m3 and its $300 in Eminence drivers that DC of 4.2 is about right. 4.2DC is about 8 ohm average. If you want a 16 ohm loudspeaker front horns and a few Fullranges are about the only choices I can think of off hand.