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
I also think that Jud needs to open his mind. I really like Dunlavy speakers but why should we assume that Dunlavy (or any other “respected” designer for that matter) is an absolute electrical genius? Other than not using Zobels, he also implements cheap (yet competent for the price) midrange and tweeter drivers, which can be easily improved with the substitution of better drivers (for instance: change that cheapo Vifa tweeter for a Morell MDT 33).

What John (and other competent designers) brings to market are extremely competent designs that compare to others at, or above their price points. For anyone to assume that a designer has not dropped the ball somewhere on a detail or two, is very shortsighted and a bit naïve.

Something to note about “Zobels”: a single Zobel network used within a crossover IS NOT THE SAME as multiple individualize Zobels networks that are wired in parallel across each of the speaker’s driver terminals. The latter is the one that Stan Warren is recommending, not the former.

Stan is an expert of how different amplifier gain stages react to different loads, and how they will sound accordingly. This is where Dunlavy (and many other speaker designers drop the ball). If a Zobel is implemented correctly, it will be a WIN/WIN scenario with no downfalls. Each driver's voice coil has an inherent reactive inductance that if tamed, will allow the amplifier to do a better job operating that driver. With properly measured and implemented Zobel networks in place, the driver’s inherent phase vectors
are drastically reduced, allowing the amplifiers' gain stage to better react to the changing
dynamic demands that would be worse if the individualized driver/zobel networks were not in place. Again this is not the same as implementing a crossover Zobel network, which is no where near as effective as individualized driver Zobel networks.
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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Sean, I appreciate your backing me up on Zobels. In terms of my description of John Dunlavy, I want to state that I DO think he is an electrical genius! I just don't think he (or anybody for that matter) is an ABSOLUTE electrical genius. Is there anybody on this planet that knows everything?

It has been my experience that many highly respected designers of ultra high end loudspeakers, amplification and digital can miss something in their overall design execution, which although may be just minor oversights, are oversights none the less.

When we are talking about very expensive products such as $25k+ speakers, $10k+ amplifiers , or $5k+ digital that can be easily improved with inexpensive modifications, I feel that my "dropping the ball" description is very appropriate. A product at these price points should not be easy to improve with minor, inexpensive modifications.
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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I tried the zobels and in my opinion they worked very well.
first of all clarity and detail are extremely noticeable. before the zobel there was a slight smearing in the treble and the midrange that is virtualy gone now. also i was suprised how much better the bass got very tight and musical. We did one speaker at a time so we could AB there was no doubt the zobeled one was better. One thing to keep in mind if you want to try this. The parts cost very little about $30.00 and if they don't work for you you can just remove them. Once again thank's for all your input!