zobal networks ?


I would like to hear from anyone who has had experiences with zobal networks. Do they work? what is it they do?. And would anyone recommend trying them on a pair of Dunlavy Alethas. I believe this is a debatable question but i would welcome some input.
fleeceba
Zobel networks can be used in several different ways. I assume that you are talking about installing them in the speakers themselves in each section ( woofer, mid, tweeter, etc...) of the crossover network ?

I have heard through the grapevine that Dunlavy's sound noticeably better with the use of such devices. I have no first hand experience in this specific area, but know others that are interested in Dunlavy's and checked into it. Supposedly, Stan Warren is a proponent of installing Zobel's in Dunlavy's. Quite honestly, i would have thought that Dunlavy would have been using Zobel's in his design to begin with.

From personal use, i know that Zobel's increase power consumption of the speaker for a given SPL. They can also give you a notably more linear frequency response. More than a few folks have complained about a "flatter" presentation i.e. "loss of dynamics" after Zobel's have been installed though, so this is something that may not be for everyone. Most speakers that make use of Zobel's are known for being "power suckers", so the loss of dynamics may be due to requiring more "horsepower" to attain the same peak output. Sean
>
Where is there more information on zobel? Is there a website by chance? I had not heard of these before.
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
>