Slightly Different Impedence Question

[Waabs]

I remember reading here that the impedence of a cabinet changes over its frequency response.

Is the impedence lowest when the frequency response is the greatest? Say if you were looking at a graph of the frequency response and a graph of the impedence would the impedence graph be like the frequency response graph but inverted?

So when the frequency response rolls off at the high and low end the impedence the highest.

 

[Tim__x]

No, the impedance curve will generally be pretty flat with one (sealed) or two (ported) peaks at low frequencys and a slow steady rise above around 3-5K.
This is assuming no tweeter, which would flatten the high-end rise and add another peak at 1-3k. No compensation network which also flattens the high-end and no crossover which greatly complicates things, somtimes they make a nice flat but peaky response other times they're a little complicated.

 

[nonsqtr]

http://www.duncanamps.com/technical/dummyload.html

 

[Waabs]

Thanks for that guys. Very helpful.