zobal networks ?

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
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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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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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Ehider, your comments about Stan understanding how various gain stages of an amp are affected and Dunlavy ( along with other speaker designers ) "dropping the ball" cracked me up to say the least. Anyone that knows about Dunlavy's background and past products knows that he IS an electrical "genius".

As a case in point, John was building / designing super high speed / ultra wide bandwidth circuitry LONG before most of the other audio "EE's" ever thought about doing such. I would consider David Spiegel to be at the forefront of that movement in the early 70's and Dunlavy just a bit behind him. He is well versed in both AF ( audio frequency ) and RF based circuitry, understands transmission line theory, has built, designed and patented one of the most widely used antenna designs known to man, etc...

This is NOT to say that Stan does not have his moments of brilliance and is able to "work magic" by simply taking a good thing and making it better. I have owned some of his past products and am familiar with his work. This is also NOT to say that John does not cut corners on some of his production models or gets everything "right" or "as good as possible" to begin with. This also is NOT to say that i agree with all of Dunlavy's points of view, even if i do acknowledge his vast level of experience and education. There are reasons why both men are well respected in their fields.

There is one thing that i do agree with in your post though. Individual Zobel networks for each driver is a FAR superior design than trying to use a Zobel for the whole system. I have never seen anybody try to do an "all in one" network though, although i'm sure that someone has attempted it. Sean
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I completely agree with the above post now that we understand where each other is coming from. For what some of these products cost, there should be NO cost cutting or "oversights" at all. Then again, MOST of the profit on these items is NOT made by the manufacturer but by the dealer. If things were slightly reversed, we would see better products and dealers that were more motivated to work with you. Sean
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Out of curiosity, what wattage rating were used on the resistors for the various units ? Did you "zobel" all of the drivers, just the mids or woofers, etc ??? Sean
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