JBL 130A grey frame 8 Ohms paper cone 21057

[iamhifi]

Hello,
To hose wit knowledge
I will like to know if JBL ever made 130A grey frame that reads on decal 8 ohms with the typical paper roll edge cone of the 60's and the cone reads 21057. Also one measures 5.3 ohms and the other 6.1, is this in range, because my D130 pair measure 6.0 ohms on the dot.
Thanks,
Angel

[script56]

Here's a similar cone. Same number, but 16 ohm.

[iamhifi]

Thanks, but this one reads 8 ohms on the magnet decal and the cone is all paper, what concerns me is the 5.3 ohms, is there a lot of difference with the 6.1 ohms or is it within spec.

[iamhifi]

Correction 5.3 ohms and 6.3 ohms

[script56]

They're within spec. I've seen 8 ohm speakers read 4 dcr before

[iamhifi]

so there is such JBL 130A grey frame all paper cone 8 Ohms on the magnet decal?

[Horn Fanatic]

Hello,
To hose wit knowledge
I will like to know if JBL ever made 130A grey frame that reads on decal 8 ohms with the typical paper roll edge cone of the 60's and the cone reads 21057. Also one measures 5.3 ohms and the other 6.1, is this in range, because my D130 pair measure 6.0 ohms on the dot.
Thanks,
Angel

Greetings -

The "impedance" printed on the label is a nominal impedance. For example, a typical 16 ohm speaker DCRe would read anywhere from 11 to 15 ohms. The DCR is not an impedance, it is the resistance of the voice coil. Impedance is frequency dependent, which includes three elements: The DCRe, the reactance of the inductance, and the reactance of the capacitance. For example, the electrical, acoustical, and mechanical reactance of a loud speaker is thus: 2 times Pi times frequency times inductance, 2 times Pi times frequency times acoustical mass, and 2 times Pi times frequency times mechanical mass. The reactance of the capacitance will be; 1 divided by ( 2 x Pi x f x Ce, or Ca, or Cm ). The fancy approach would be: |Ze| = square root of ( Re squared + ( Xe - Xc ) squared ), although excluding Xc would be fine. Try that method using the free air resonance frequency, and see what you get.

On a vector graph this equation is also used to determine phase angle, the resistance is the real number, and the reactance is the imaginary number, also written: |Z| = square root of ( R squared + jX squared). The vector graph will illustrate at which frequencies the speaker is either in a resistive or reactive mode. A high reactance is not a particularly good mode to operate in, as it results in negative energy. The higher the frequency, the higher the reactance. The impedance of a typical loud speaker can reach approximately 400 ohms before the frequency response dramatically drops off due to the limitations of the voice coil. I find it odd that some folks are so concerned about an impedance load, when the impedance load is all over the map when reproducing music.

To determine the resonance frequency of a loud speaker: 1 divided by ( 2 x Pi x ( the square root of (Ce, or Ca, or Cm x Le, or Ma, or Mm)).

2 x Pi x frequency is called the angular frequency. Thus; Xe, Xa, Xm, =2 x Pi x f x the reactive elements of a loud speaker. Where the impedance comes in will be what is called the magnitude: |Ze| = Square root of ( DCRe squared + jXe squared ). By manipulating the frequency of the reactance it would be a simple task to determine at what frequency will result in an 8 ohm impedance.

Keep in mind, the analogies need to be kept in the same family. To determine the acoustical impedance, one must know the acoustical resistance of the piston area, and the acoustical mass of the piston area. |Za| = Square root of ( Ra squared + jXa squared ) .

BTW - the equation to determine magnitude is also used in trigonometry. Say you want to know the length of the hypotenuse of a square or rectangle. L = square root of the ( adjacent side squared + opposite side squared ), or in the case of a square, the two sides are equal in length.

H.F.

Also, even though the 130A and D130 use the same cone, an aluminum dome on a 130 does not make a D130, They are two completely different components. My guess is that they do not share the same voice coil assembly. The T-S parameters will bear this out. The speaker that is a T-S parameter dead match to the 130A is the 2220A. The only difference being the surround upgrade on the 2220.

[Horn Fanatic]

so there is such JBL 130A grey frame all paper cone 8 Ohms on the magnet decal?

I believe the 130A is a 16 ohm, and the 130B is a 32 ohm. I do not recall ever seeing an 8 ohm 130, but I've never seen a dancing bear smoking a Cuban cigar while wearing Birkenstock sandals either.

[iamhifi]

Thank you, after looking at the catalog library, I see that 1967 the 130A was gray and offer in 8, 16, 32 ohms, so such speaker exist.

[iamhifi]

In 1964, 66 was 130A 16 ohms and 130B 32 Ohms, in 1967 an all grey speaker 130A is a 8 Ohms and 130B 16 Ohms and correcting myself there was no 32 Ohms.

[Horn Fanatic]

In 1964, 66 was 130A 16 ohms and 130B 32 Ohms, in 1967 an all grey speaker 130A is a 8 Ohms and 130B 16 Ohms and correcting myself there was no 32 Ohms.

http://s279.photobucket.com/user/cal..._0014.jpg.html

[BMWCCA]

Also, even though the 130A and D130 use the same cone, an aluminum dome on a 130 does not make a D130, They are two completely different components. My guess is that they do not share the same voice coil assembly. The T-S parameters will bear this out.

The D130 used a four-inch aluminum edge-wound voice coil. The 130A used copper.

[Maron Horonzakz]

I have a pair of 130 woofers with 32 ohms,, both have the same identical serial number,,,How can this be???

[Horn Fanatic]

I have a pair of 130 woofers with 32 ohms,, both have the same identical serial number,,,How can this be???

I have seen many 130A's with the same serial number. I assume your speakers have the paper label? I have seen several 175 drivers with the same serial number also. Those would be the grey drivers with the Alvin Lustig Lansing Signature decal.

H.F.

[Horn Fanatic]

The D130 used a four-inch aluminum edge-wound voice coil. The 130A used copper.

Thank you.