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[Bob L. Wilson]

tidbit....

In 1991, Dugan's patent expired. Competing manufacturers began to bring the Dugan algorithm directly to their product designs. In 1993, Travis M. Sims, Jr. of Lectrosonics (Rio Rancho, New Mexico) was granted a patent for a sound system with rate controlled, variable attenuation of microphone inputs, including the Dugan algorithm as well as loudspeaker zone attenuation when in close proximity to an active microphone.[28] The loudspeaker zone part of the patent cited a 1985 patent for proportional amplification by Eugene R. Griffith, Jr. of LVW Systems of Colorado Springs, a commercial audio contractor.[29] In 1995, Sims and Lectrosonics gained another patent for an "Adaptive proportional gain audio mixing system" which incorporated a number of ideas including the Dugan algorithm for maintaining a constant total gain of all the inputs.[30]

In 1996, Dugan came out with the Model D-1, a speech-only economy model that did not offer the music system of the Model D.[15]

In 1997, John H. Roberts (our hero) of Peavey Electronics was granted a patent for an automatic mixer priority circuit, enabling a hierarchy of logic weighting that allowed selected signals to push forward in the mix when they are in use, while still maintaining the useful constant unity, gain-sharing relationship first described by Dugan. The hierarchy enabled a host, moderator or chairperson to speak over other participants and retain control of the discussion.[31] Peavey's Architectural Acoustics division used three levels of hierarchy in their 1998 "Automix 2" product, placing the first- and second-most influentially weighted sources at inputs 1 and 2, respectively.[32]

I am left wondering why somebody hasn't/didn't combine Shure's comparator circuit that seems to be the best part of the SCM810 with Dugan style gain sharing it seems like that would be better way to ensure a single signal never opens more than one mic.

[John Roberts {JR}]

not sure what a tidbit means, looks like it was cut and pasted from somewhere (wiki?).

According to the USPTO database Dan's original patent #3,992,584 issued in Nov 1976 (filed May 1975). Back then patent duration was 17 years from issue, or 20 years from filing date, so late '93/mid '95 as I count. In '95 the law was changed to 20 years from filing date for all new patents.

I recall timing the introduction of Peavey's first automatic mixer such that it was not infringing with Dugan's '584 patent.

Regarding my improvement patent in '97, while I came up with the concept independently I have discovered since then that there may have been prior art. Also kind of academic since it was never challenged in court, and I assigned it to Peavey in '97, so I don't really have much say about it one way or the other.
----
Ironically perhaps my FLS patent that should be rock solid, was not strong enough to shut down an IMO blatant imitator in court. Life is not as clear cut as we think, and sometime "my lawyer's better than your lawyer" wins.     

JR

PS: I am not a role model.

[John Roberts {JR}]

I am left wondering why somebody hasn't/didn't combine Shure's comparator circuit that seems to be the best part of the SCM810 with Dugan style gain sharing it seems like that would be better way to ensure a single signal never opens more than one mic.

In the sundry digital implementations you certainly could, but IMO there is no real benefit from that. The standard Dugan gain proportioning algorithm expands small level differences between mics by multiplying the level difference by a similar gain difference, so a second mic that is picking up signal down 4 dB gets doubled down 8dB and so on.

I even designed a small dedicated unit with only 4 inputs for the specific (church) application when a wireless mic wearer walks up to a podium mic. The algorithm expanding the natural level differences pretty much insures you will never get the same level from both mics that would cause deep comb filtering.

I don't recall the details but I think MediaMatrix may have included the hold last mic on feature, the parsing for first mic on, is mainly a work around for systems that couldn't use the Dugan approach and I could imagine an issue if two different talkers start at almost the same time. While maybe it's OK to step on the second talker(?), Dugan doesn't).  I don't know if Shure tests for coherence between signals to discriminate between same source or different. The Dugan algorithm by the nature of how it works ducks coherent sources more than incoherent sources (I said it was elegant).

Of course in the digital domain you could do almost anything you want.

JR

[Nick Simon]

sure you are... as well as a lot of folks on here..  I look up to folks I can learn from... it's called respect... something severely lacking in today's world, sorry to say..

[John Roberts {JR}]

sure you are... as well as a lot of folks on here..  I look up to folks I can learn from... it's called respect... something severely lacking in today's world, sorry to say..

I appreciate the respect. 

I was making word play on something Charles Barkley said when he was criticisized for not setting a good example, for young fans back when he was a professional basketball player.   

JR

[Tim McCulloch]

I appreciate the respect. 

I was making word play on something Charles Barkley said when he was criticisized for not setting a good example, for young fans back when he was a professional basketball player.   

JR

My neighbor's kid was so disappointed by that statement that he had to rename his dog, until then known as Barkley.

[Nick Simon]

I appreciate the respect. 

I was making word play on something Charles Barkley said when he was criticisized for not setting a good example, for young fans back when he was a professional basketball player.   

JR

I got that... it's turruble...

[Alfredo Prada]

But don't have one.

What are your alternatives in the digital realm?  Obviously ducking, but what if you have more than two channels?

I end up riding each fader as best I can, eyes nervously twitching, desperately scanning the stage trying to anticipate who will talk next.  Clearly not the best choice.

How are y'all working without a Dugan on Yamaha/Digico/Avid etc. and what works best for you?

This new product should be the next alternative:

http://www.shure.com/americas/news-events/coming-soon/scm820-digital-intellimix-automatic-mixer

[John Roberts {JR}]

This new product should be the next alternative:

http://www.shure.com/americas/news-events/coming-soon/scm820-digital-intellimix-automatic-mixer

You mean the next Shure.

I have been following the technology for a long time and these days you can perform A/D and D/A at near price parity to using a decent performance VCA (not many choices there) and surrounding glue circuitry.

When you consider that the AM gain crunching calculations can be performed very inexpensively in the digital domain, this could cost less total to manufacture than using analog technology.

I consider this a natural evolution driven by technology and price. While i must repeat the obvious, software running on existing (already there) hardware is even cheaper than adding redundant hardware. Dedicated AM (IMO) will still make sense for permanent fixed install applications.

JR

PS: Who knows maybe Shure will finally offer Dugan algorithm as one of their modes. 

[Bob L. Wilson]

This new product should be the next alternative:

http://www.shure.com/americas/news-events/coming-soon/scm820-digital-intellimix-automatic-mixer

Very similar feature set to the Lectrosonics units. It will be interesting to see how it sounds in use. The SCM810 was getting beyond long in the tooth and losing market share left and right to digital solutions, I am surprised Shure waited so long to update it.

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