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.
Measuring impedance with multimeter
I am measuring a new full range speaker impedance that is advertised as 12 ohms and I am getting a consistent reading of 4.2.
I checked the multimeter on another bookshelf speaker advertised as 6 ohms nominal and I get exactly that.
I am using a multimeter at the speaker leads not connected to amp.
Why is this reading so low?
I checked the multimeter on another bookshelf speaker advertised as 6 ohms nominal and I get exactly that.
I am using a multimeter at the speaker leads not connected to amp.
Why is this reading so low?
- ...
- 24 posts total
This is an area of interest for me too. A close friend's church had lots of PA gear stolen. I'll be doing the installation and don't want to be attaching a new power amp before testing the long speaker cables. Strangely another friend's church needs work on their 70v system with 8 speakers in the ceiling. I've been running sound for churches for decades, not doing installations. So I need to purchase something reliable. There are relatively inexpensive devices available that will test AC impedance for audio applications--not DC resistance. https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=speaker+impedance+meter&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=impedance+meter The more expensive ones will test impedance at various frequencies. Some will also calculate "watts" for those testing a larger number of ceiling speakers running on a commercial 70v system, etc. http://www.gold-line.com/zm1.htm There is a software based app that has lots of bells and whistles. The package is very pricey due to the required $500 audio interface plus the app https://www.studiosixdigital.com/audiotools-modules-2/speaker-test-modules/impedance-meter--sweep.ht... The inexpensive Chinese impedance meters only test at 1khz. https://www.ebay.com/itm/Digital-Audio-Impedance-Tester-LCD-Display-Speakers-System-Resistance-Ohmme... The choice of 1khz seems strange to me. My understanding is that the standard frequency for testing woofer impedance is 400hz. You can see why 400hz is more suitable for testing speakers since impedance varies greatly according to frequency! https://www.studiosixdigital.com/_Media/impsw5.png |
Post removed |
- 24 posts total