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View Full Version : What is the Final impedance?



fire919
08-14-2010, 01:34 PM
I have a pair of alpine spr-17s.....when connected to the crossover, what would be the final impedance that runs from the crossover to the amp...also what are the impedance of both the woofer and tweeter seperately.thanks.

keep_hope_alive
08-14-2010, 03:12 PM
woofer is 4 ohm, tweeter is 4 ohm. the crossover divides the signal to each so the amp only sees one speaker at a time, thus the amp sees 4 ohm nominal.

in reality, impedance varies with frequency, so the impedance plot of a component speaker system looks like this:
http://i38.photobucket.com/albums/e128/phat_funky_beats/audio%20testing/IDCX62_comp_R.jpg

This is a measurement of an Image Dynamics CX62 wthic is a 2 ohm woofer and a 2 ohm tweeter through the supplied crossover. Notice that it isn't 2 ohm very long or often. But the minimum impedance is referred to as the nominal impedance to offer safe amlifier operation.

Here is an Eclipse 8971 with external crossover, rated 4 ohms per driver:
http://i38.photobucket.com/albums/e128/phat_funky_beats/audio%20testing/Eclipse8971_WT3_crossover.jpg

keep_hope_alive
08-14-2010, 03:15 PM
by a pair i am assuming you mean one left and one right, powered by a two channel amp, one speaker per channel.

if you are going to run two speakers per channel (such as front and rear right to one channel) then the amp will see the parallel combination of 4 ohm and 4 ohm which is 2 ohm nominal.