zobal networks ?

I have no idea as to where you can find a good yet simple explanation of how or what a zobel does. In layman's terms, it is simply an impedance compensation device typically comprised of a resistor and capacitor wired together in series. This in turn is wired across the load ( or part of the load ) in parallel. Changing the parts values ( amount of resistance, capacitor values, etc..) changes the "tuning" of the circuitry.

These "circuits" can be used to help stabilize circuitry from oscillation, maintain relatively constant impedances, etc... Since it is connected at the output of a device, it too becomes part of the load and dissipates some of the signal. As such, resistors and capacitors used in these circuits need to be able to dissipate both sizable amounts of power and heat when used at speaker level. This is the type of "impedance stabilization" that Goertz supplies with their speaker cables ( if needed ).

In terms of zobels used for speakers, what one is trying to accomplish is an even impedance across the audio spectrum. Even though a driver may not be operating at anywhere near full output ( like a woofer at 8 Khz ) due to a signal dividing / crossover network, it is still part of the electrical load that the amp sees and the acoustical output that you hear. The use of a zobel helps to keep reactance down to a minimum and reduce the driver output level that is trying to operate "out of band".

As to Fleeceba's idea of mounting them directly at the driver, i see no problem with such. Most designs incorporate them into the crossover board for ease of wiring / configuration during mass production. Since you're dealing with something that is already a "finished product" and don't want to muck with the factory product, your approach seems the best and easiest to take. Sean
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Hi Fleeceba,

Stan Warren recommend doing exactly what you are doing, and knows the correct values, though you may have to get the inductance measurements for each of your drivers for best results. He says it reduces smearing, a phase related distortion that exists because the driver's inductance has not been compensated for, or words to that effect. It is supposed to make a very big difference, which is said to be even more noticeable if you are used to electrostatic or ribbon speakers.

Hope this helps,

Lou

Lou thank you and everyone for your input i've talked with Stan Warren and he'll be coming over to my house tonight.
we'll zobel one speaker and see how it sounds.

Due to mass confusion (!!!), Stan Warren's number was deleted. In case someone wants to contact him, he can typically be reached at (541) 344-3696 in the evenings. Sean
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A zobel for a particular speaker is a basic part of the design of the crossover - the single most difficult part of loud speaker design! Dunlevy has forgotton more about crossover design than most designers will ever know, let alone the rest of us.
Leave your speakers alone. Home rolling of speakers is grand folley, and you can certainly change the sound but will you ever know if is actually better.

Best regards, Jud Barber - Joule Electra