Power 2 Ohm Impedance Speakers

Hi guys, I have designed a 2-way passive crossover using the VituixCAD program. I have simulated using a 4-ohm tweeter (20 W) and an 8-ohm (80W) drivers. I am happy with the results so far. But have some doubts too though.

I managed to achieve a 2-ohm flat impedance curve for the crossover. Now the question is, is it too low?

If I build these speakers, what do you think I should keep in mind so that I can power them? Ideally, they will be used as bookshelf speakers.

I will be attaching images, do have a look at them and point out if I made a mistake somewhere.
 

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I was trying to get sort of a flatter impedance curve.

And what about the impedance curve one below (1st attachment)? I used a different order to achieve that.

Edit: Here's the impedance curve without the 3-ohm resistor (2nd attachment). Quite different!

I wonder why?
 

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Last edited:

rayma

Member
2011-04-29 8:37 pm
Simple, the parallel resistor sets a maximum possible total impedance,
no matter how high the rest of the crossover/drivers go.

The impedance over 5k is still rather low, can you redesign with only
series resistors for the tweeter, and remove the shunt resistor across it?
Is the tweeter available in 8 ohms?
 
Last edited:

4real

Member
2004-05-27 8:51 pm
Steyl
The proper way to flatten impedance would be to use a zobel network. You can calculate one right here: Speaker Zobel / Impedance Equalization Network Circuit Calculator

However as noted before, as long as you don't have a tube amp, it is generally not needed.

Also: what's up with the 2 ohm resistor in series with the woofer? That will lower efficiency and will also influence the low end.
 
I was trying to get sort of a flatter impedance curve.

And what about the impedance curve one below (1st attachment)? I used a different order to achieve that.

Edit: Here's the impedance curve without the 3-ohm resistor (2nd attachment). Quite different!

I wonder why?

You don't do that with an single resistor, you need an RC network, where the R is higher than the impendance of the speakers. Otherwise your impendance curve gets to low and may damage the amp. I use those RC networks also often, and it can help to flatten the impendance, but those need higher values on the resistor and a fairly high value on the C'(capicitor).

This is how i do it for a speaker i've build for myself, the actual values are still different now, but the principe is the same.
 

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