>> Zobel Network , Re or Rz in Calculation ? <<

[presscot]

>> Zobel Network , Re or Rc in Calculation ? <<

Hi guys,

I'm improving my diy speaker and there has a problem with woofer's sound, too much mid-frequency.
This is my woofer's spec, SEAS H602 P17REX/P.

An externally hosted image should be here but it was not working when we last tested it.

note: My woofer hasn't any filter, it's directly wired. Only the tweeter has a 2nd order high-pass filter.

So, I've tried to solve the problem till someone suggested me to make a zobel network and then calculate it from the free program on the internet.

But, the programs made me confused when the first site told me to use..
R = 7.6 ohms, C = 16 uF

and the second site told me to use..
R = 7.6 ohms, C = 10 uF

I've sought the truth and found that..
The first site use Re, DC Resistance of the driver which is 6.1 ohms from the speaker's spec sheet, in calculating.
While the other use Rc, the calculated Zobel resistor which is 7.6 ohms, in calculating.

And that's the Rc = Re *1.25

Which one is true ?

 

[picowallspeaker]

Hi,
I fear that the zobel would be effective only after the lowpass network, which hadn't been used. So it would be in parallel also with the tweeter XO network, which adds itself a change in impedance.

( still 'transferring data'...the image is too big ! )

 

[presscot]

Hi,
I fear that the zobel would be effective only after the lowpass network, which hadn't been used. So it would be in parallel also with the tweeter XO network, which adds itself a change in impedance.

( still 'transferring data'...the image is too big ! )

Oh sorry , I've edited my image. 🙂

 

[presscot]

I found this site has different in calculating method.
Passive Crossovers, Zobel Calculator

It's require to fill the "Frequency Impedance Doubles" instead. So, I tried to fill random-frequency and found that

at 1,600Hz the site told me to use R = 7.6 ohms ,C = 16 uF.
at 2,500Hz the site told me to use R = 7.6 ohms ,C = 10 uF.

What is the site going to tell me ? (about the frequency filled)

 

[system7]

I'd look at a 6.1R DC woofer with a 0.6mH Le inductance, and go for 7.5R and 10uF. I am kinda good at this stuff. 😀

http://www.seas.no/images/stories/vintage/pdfdataheet/h0602_p17rexp.pdf

And so does the only Zobel calculator I trust:

Impedance Equalization (L-Pad) Circuit Designer / Calculator

Parts List
Capacitor
C = 10.32 uF
Resistor
Rc = 7.63 Ohms

Not bad, system. 😱

It's a horrible woofer on frequency response, IMO. Polypropylene an all that, but really...what to do with it?

Definately needs a bass coil though. Maybe 2.2mH. Can't think about the shunt component right now.

Your image is causing me loading problems too. LOL

 

[system7]

Well, actually it's not a million miles away from the H1520-08 U16RCY/P.

This might help you:
SEAS CURV

I quite like that. 🙂