Impedance Cyclone

[joerg]

Matt just told me that the Cyclone has a nominal Impedance of 8 Ohms. As i tested the one i got yesterday it just says 6 Ohm´s on my DMM. After changing the batteries on the DMM same thing. I called my friend in austria today that has the other two i bought and he tested them as well.
Same result with 6 Ohms.

So does the clone have 6 or 8 Ohms now?

Greetz
Joerg

Found the info in the manuals! But what causes my clones to have 6 Ohms only?

[andy600rr]

The 8 ohm rating is a nominal impedance. In real world conditions, it's quite rare that a driver would measure up to its nominal rating. Grab a normal 4 ohm driver and meter that...... more than likely its .2 - .5 ohms lower than its 4 ohm NOMINAL rating.

No need for concern.

http://en.wikipedia.org/wiki/Nominal_impedance

[fuzzysnuggleduck]

From: http://www.epanorama.net/documents/audi ... dance.html

Measuring speaker nominal impedance
If you just want to find out the nominal impedence of the speaker e.g. ist it 4, 8 or 15 ohms then there is a rough & ready way. Just use your multimeter to measure the DC resistance of the voice coil i.e. across the speaker terminals (with nothing else connected) and multiply the answer by 1.3. So if the DC resistance is say 6 ohms then the speaker is nominally 8 ohm impedance.

More complete analysis with minimal equipments:

a) Measure the DC resistance across the voice coil with the driver disconnected. The ohm value you get, is the lower impedance bound of the driver. Add an ohm or two to this value, and you should be at the nominal (rated) impedance of the driver.
b) Connect a pot in series with the driver voice coil and then to the amp.
c) Connect frequency generator or CD player with suitable test CD in it to the amp input, and start walking up the frequency scale in steps. For each step, measure the voltage across the voice coil terminals and then across the pot. Adjust the pot until both voltages match. Now shut down the amp. and measure the resistance across the pot. This is the driver impedance for the current drive frequency.

This approach is not the most accurate, but it needs minimal set of measuring equipments: multimeter, signal generator and a potentiometer of 50 ohms 5-10 watt. The clear advantage of this approach is that the accuracy of the measurement is not affected by the multimeter frequency response (their AC range is designed to show right values at around 50 Hz range and at higher frequencies the accuracy can drop noticably depensing on the meter construction, but this does not affect in this measurement because the absolutely correct AC voltage values are not needed). Warning, KEEP DRIVE LEVELS TO SPEAKER VERY LOW. High levels of sustained sine wave can up the driver voice coil.