Asathor - a JBL 4367 Clone

[thimios]

Many DIY amplifiers that I have in my collection.😉

 

[thimios]

What is the right method measuring impedance when woofer mounted to the cabinet?
Do I need to measure with or without crossover connected?

 

[thimios]

A very first configuration to the crossover.

 

[Rese66]

What is the right method measuring impedance when woofer mounted to the cabinet?
Do I need to measure with or without crossover connected?

It depends on what you want to measure.
You can measure both with and without X-Over. You won't know if everything is working properly until you measure the finished speaker with X-Over.
You only measured the woofer in the cabinet, right? That looks fine.

I did find a mistake with the crossover, though. You soldered the 560µF cap in the wrong place. It goes in between the first 2.2mH coil and the two 15µF caps. You have inserted it after the two 15µF caps.

 

[Rese66]

 

[thimios]

Thanks Resse66.
What I have measured was the woffer in free air,not into the cabinet!
I will measure woofer in the cabinet without crossover latter.
Thanks for the mistake finden!

 

[thimios]

Here it is.
Measuring woofer impedance in the cabinet,no crossover.

 

[thimios]

Yellow trace is without crossover,green is with crossover.
Both in the cabinet
No damping material yet.
Mistake corrected 🙂

 

[Rese66]

Now I was already shocked, but then I read that you still have no damping material in the box.
Please make sure you put it in, otherwise the measurements will be worthless.

Is everything else already sealed?

 

[thimios]

Yes, everything else already sealed.

 

[thimios]

To learn something here.
Are these red areas an indication of a damping material absent?

 

[Rese66]

To me it looks more like a leaking enclosure, but I have never measured the woofer without damping in the enclosure. Therefore, I can not say for sure. But it is a bit strange.

 

[thimios]

Damping done.

 

[thimios]

Here the impedance plots after damping with crossover connected.
According to what I read these plots is what expected to a bass reflex cabinet🤔

 

[thimios]

Here is the impedance plots in the cabinet with damping material BUT no crossover connected.
Now I think that is clean ,the second impedance peak at 1.174khz is a crossover result.

 

[Rese66]

Now it looks much better.
Yes, the peak at just over 1kHz comes from the X-Over, that is correct.
With bass reflex, there are two peaks in the bass range and the lowest point between the two peaks is the tuning frequency.

 

[hell67]

nice work 👍 I follow with great interest. Well done

 

[thimios]

Ok,thanks.
I have another test that confirm this.
In this plots only the crossover is connected.Woffer is disconnected.

 

[thimios]

Here is the plots with the crossover connected and a resistor 8R2 connected in woofer's position.

 

[thimios]

Hi Resse66,please what is the Fc of this closed box?
I ask to know if more damping is necessary.
Thank you