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.
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.
Attachments
The 3 ohm resistor. Why is it there?
To make the impedance seen by the amplifier more constant, but it's terribly wasteful and has to go.
With a ss amp it won't be of any use anyway. Without that, the system load impedance should be tolerable.
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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?
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?
Attachments
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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?
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?
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Well if I remove the shunt then the result is very similar to the second attachment.
Since the impedance is around 3.7 ohm if I keep the shunt. So I was thinking maybe I could power it up with an amp which has a minimum load of 4 ohm.
Nope, the tweeter is available in 4 ohms only.
Since the impedance is around 3.7 ohm if I keep the shunt. So I was thinking maybe I could power it up with an amp which has a minimum load of 4 ohm.
Nope, the tweeter is available in 4 ohms only.
It doesn't work like this. Your Voltage source amplifier has an output impedance near zero. There is no primary need for any resistor to make the impedance look flat because the amp does it all for you.with an amp which has a minimum load of 4 ohm.
Since the impedance is around 3.7 ohm if I keep the shunt. So I was thinking
maybe I could power it up with an amp which has a minimum load of 4 ohm.
A lot of amps could have trouble with an impedance curve above 5k like that.
Do you have a tube amp? Try a different crossover topology for the tweeter.
Hmm, in this case no. Do you have a link so we can read it too?flatter impedance curve translates to better efficiency.
Rayma and I are uncertain what your amp is and it makes a difference to our advice.
Hmm, in this case no.
Definitely agree, a little EE101 study is called for here.
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.
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.
Attachments
- Home
- Loudspeakers
- Multi-Way
- Power 2 Ohm Impedance Speakers