Dunlavy Audio Labs Archive - From the mind of a "Legend"!

[Speedygg1]

Pete, the schematics for the SC-IV's were reverse engineered already on this DIYAudio thread.

Here's a link to the diagram!

 

[Speedygg1]

Thanks for posting. Cant tell from the schematic, but what are the crossover points?

 

[Speedygg1]

John didn't believe in exotic, expensive electronics and used designs he felt performed well and weren't marketed based on bs. He liked Adcom and John Ulrich's Spectron amps and used both in his demo room and at CES. The boys from Edge bought a pair of speakers from him at accommodation pricing but I don't remember him ever using their electronics. Joan heard that they were trying to sell the speaker for a profit and was pretty upset and thought that she been duped. She wondered if I knew them but I didn't. Also John used a couple of amps from engineers he knew. One was designed and built by an Air Force Colonel that taught at the Air Force Academy and another from an instructor at Colorado College. At one CES I attended, Krell was demoing with Dunlavy speakers. I had several Krell amps, the last which I still have, an FPB-600, which makes a very synergistic match. I never saw tubed electronics in John's system.

Jeff Rowland's facility was only about a 10 minute drive from DAL and at one time Jeff had a pair of John's speakers in his demo room. For some reason they didn't really associate with one another very much. One time the three of us went up to Steven Stone's home outside of Boulder when he was reviewing the SC-VI's and had a pair of Jeff's amps and a SigTech unit for review, and another when we all took a hike up to Devil's Head Lookout Fire Tower. I think they respected each other professionally but didn't have a social relationship.

Thanks for all your interesting information above John Dunlavy.
I’ve found a white paper describing his experimental “Magnus” speaker describing its specs, dimensions,etc.
Was it ever completed, did you see it, and if so, what did it look like?
Thanks in advance.

 

[SimplySound]

Just found some info on the avsforum board... thanks to those folks, I will post here for posterity the Sigma (SC-IVa follow-on) info... Thanks to "Shocked One" for their post....

"Another not so common model was the very elegant Sigma. They were basically souped up SC-IV/A's, with even more refined crossover networks, and thicker walls resulting in less flex / better bass. They had rounded corners everywhere and their grills didn't come all the way out to the edges like the regular Signature Collection speakers. They used the same drivers as the SC-IV/A's, but weighed 250 lbs @ $10k, as compared to the SC-IV/A's 190 lbs @ $8k or the SC-IV's 180 lbs @ $6k."

 

[SimplySound]

Thanks for all your interesting information above John Dunlavy.
I’ve found a white paper describing his experimental “Magnus” speaker describing its specs, dimensions,etc.
Was it ever completed, did you see it, and if so, what did it look like?
Thanks in advance.

Yeah, I posted the Magnus specs on Page 1, but never found a picture.... could you upload that white paper Speedy?

 

[onwardjames]

There is no better education in HiFi than getting off one's arse and going to hear as many systems as possible.

QFT. AKFest2008, while a major drive for me, was completely worth it.

I heard systems that blew the lid off of "possible".

 

[SimplySound]

I found this from a poster in avsforum.... as Doyle mentioned above, seems John liked Adcom amps...

"The first time I went to Dunlavy Audio Labs, John Dunlavy was using an Adcom GFA-5800 on the speakers he was playing. His comment was that the Adcom was a great amp, and that he used it a lot."

 

[Speedygg1]

Yeah, I posted the Magus specs on Page 1, but never found a picture.... could you upload that white paper Speedy?

What i have is a downloaded copy of the two sheets of specs that you posted for the Magnus.
I communicated with a guy on Face Book,that runs a page for active loudspeakers.
He told me a short while back, that he caught up with someone who worked for Dunlavy and that the Magnus was never built.
My loudspeakers are homebuilt and somewhat modeled after the SCVI, minus the 15” subwoofers.
Tweeter, two 5” mids, two 8” woofers. Tri amped.
Although the specs described of the Magnus are tempting to try to build, it seems it was a myth.

 

[SimplySound]

The Magnus may have indeed been "vapor-ware".... seems strange they would have a Spec Sheet for it without any being built. I bet there's a prototype or two somewhere in Colorado Springs!

Now the Millennium has always intrigued me and there are at least three people in the world who own a pair according to Audio Review! But the other one that kinda gets me, is I've never seen anyone mention that they actually have a pair of Sigmas!

 

[SimplySound]

Switching gears a bit, let's talk about the final designs of John Dunlavy! I'm specifically referring to the "downward-firing" woofer designs in the Aletha, Cantata and finally the SC-3a. Some say the bass reproduction & control of these rivaled the SC-IV! Anyone with a pair and some experience compared to other Dunlavy's?

Here's a link to a review of the Cantata done in Finland back in 2000.

 

[SimplySound]

Question I have is did John "voice" the SC-3a's? They were so late in the production cycle and John may have already been in the process of turning over the operations to Wybron. They were introduced in 2002 and from what I understand, John had already sold DAL to them in 2001. That doesn't mean that what ever stock had been built up wasn't established when John was on board, but it makes me wonder!

Specs:

The SC-III.A was introduced in 2002 as a cabinet revision of what had been the Cantata (and before that the Aletha). The III.A is a three-way with forward-facing M-T-M plus a downward-firing 10” (sub) woofer. The speaker is a sealed box with stepped baffle and first-order crossovers.

Woofer (1) 10" (down-firing)
Midrange (2) 6.5"
Tweeter (1) 1" soft dome
Frequency Response 27Hz - 20kHz, +/- 1.5 dB
Dimensions 52"H x 11"W x 14"D
Weight approximately 90 lbs each
Sensitivity 90dB
Impedance (Nominal/Min/Max) 4/3/6.5

 

[SimplySound]

Here's a review of the Cantata done in 2001 by Sensible Sound...

 

[DCDoyle]

John built one prototype of the Magnus. Moses Wadia developed the digital components consisting of time alignment, crossover points and fir filters for frequency response correction of the drivers. All of the parameters and filter values had to be calculated and entered manually which took hours. I heard it once in John's listening room. We sat together and John played his normal demo material. There was an unusual very faint background noise which modulated with the dynamics of the of the output. I mentioned it to John and agreed that he heard it too and felt that it was quantization noise generated in the ADC. IIRC, the drivers were mounted in more of a large box than his standard designs. John scrapped the development shortly after. After that, I tried to hook John up with Ron Genereaux, developer of the SigTech technology. We had one meeting in Las Vegas where John brought a couple of his engineering friends to pick Ron's brain. John felt that they gleaned enough information from Ron to develop their own digital components and software. Ron had run into people before that thought they could learn the ins and outs of DSP application without his engineering background and experience. His CV speaks for itself. (To see Ron's background; https://www.linkedin.com/in/ron-genereux-bab28216/) After returning to Colorado John's team found that they didn't have the ability to do what John wanted hence the Magnus project was scrapped. I have no idea what happened to the Magnus prototype.

references: https://www.stereophile.com/asweseeit/1092awsi/index.html

 

[SimplySound]

Thanks so much again Doyle for providing input into this thread, you are a wealth of knowledge on the development of the legend that is Dunlavy! I for one appreciate your insights. Thanks again and perhaps one day our paths will cross. Do you reside in C-Springs?

 

[DCDoyle]

I lived in SW Denver for 31 years from 1978 until 2009 when I moved to the NW Suburbs of Chicago where I currently reside.

 

[Brent71]

I'd never gotten to hear a pair of Dunlavy's until earlier this summer. I bought a pair of SC-IIIs about 100 miles away from me for a really good price and instantly fell in love with them. Then about a month ago a really nice pair of SC-IVs were posted on Audiogon about 300 miles away in Fenton, MO and I decided I had to have them. They are very different than the 802s that I've owned since 2001, and I wish I could have had the SC-IVs years ago! The SC-IIIs are extremely similar to the IVs, just less bass, but both really benefit from stereo subs.

Thanks to those who posted all of the good info, I appreciate it as a new Dunlavy owner.

And as of the last week of October I'm now the owner of a pair of SC-Vs! I haven't gotten them into the house and setup yet, but hoping for that to happen this weekend.

 

[theophile]

Nice Brent.

 

[turboyam]

Lucky you!!!. I had a listening session in a nicely settup, audio store's rooms, demoing a pair of SC-IV's and ohhh!!!

 

[Brent71]

Lucky you!!!. I had a listening session in a nicely settup, audio store's rooms, demoing a pair of SC-IV's and ohhh!!!

I've been extremely happy with my IVs, and honestly could have lived with them for many years to come, but these were such a good deal that I knew I'd regret it if I passed them up. I've read several comments over the past year that John considered the Vs the best speakers he ever built, so they should be amazing.

 

[turboyam]

How did you find the bass in your settup/ room???