2. misc-audio
  3. 195115-94506

Changing out 8?ohm for a 4ohm...

I've got an old pair of 3 way speakers (Avance Epsilon 980) rated at 4ohms and 89db sensitivity. (4) 7" ScanSpeak drivers #8544-09. Now, I thought the number designation on ScanSpeaks means that '8' stands for 8ohms. If so, how can they be 4ohm speakers? But my real question is: I have a chance to pick up 2 new ScanSpeak Revelators that I know are 4ohms, for a really good price. So, can I trade out just the mid woofers in these for the Revelators without screwing anything up, specifically the Revelators? Also Revelators are 92db. Bad idea? Feasible?

Amp can handle 4ohm loads no problem.

thecarpathian
viridian's avatar
viridian
5,304 posts
 

Yes, you can, but it is rather approximate. Use your meter on the resistance scale (ohms), but understand that impedance is not resistance and the impedance will generally be noticeably higher than the resistance measurement.

Sorry that math is complicated, but if using two drivers with with the same impedances, just divide by two. So two 8 ohm drivers in parallel will have a net impedance of 4 ohms, and two 4 ohm drivers in parallel will have a net impedance of 2 ohms. Hope that helps.

ckr1969
140 posts
 

@thecarpathian the drivers are wired in parallel

thecarpathian's avatar
thecarpathian OP
5,120 posts
 

Ah, thanks you guys. I think I'll just leave them as is.

incorrigable
104 posts
 

Engineers harness the variability of impedences among drivers as tool for phase and voicing. My Yamaha NS-5000's have 6 ohm woofers with 4 ohm midranges and tweeters. 

More to discover