As is my custom, I like to give you a "sneak peek" into my upcoming Positive Feedback feature articles, which in this case is "The Duelund-Corona 832A Project - Serendipity to Ecstasy!" article describing the Duelund CAST crossover build that Frederik Carøe and I collaborated on for the vintage Altec Corona 832A loudspeakers from the 1950s.
The performance of my vintage Corona 832A loudspeakers with their new Duelund CAST crossovers has exceeded my wildest dreams for the project, and I am thrilled with the results!
Sometime in the next few weeks, the full review will be published at Positive Feedback, at which time I'll update this "sneak peek" with a link to the feature review.
Enjoy!
Greetings friends, I hope you are doing well.
Today's feature article is about "The Duelund-Corona 832A Project" that Frederik Carøe (Duelund Coherent Audio) and I have collaborated on, but before I delve into the details of our project, let me give you a little background about Duelund Coherent Audio.
Duelund Coherent Audio is located in Fredensborg, Denmark, and is owned and founded by Frederik Carøe and Magnus Franch Pedersen, upon the insightful and uncompromising approach to the loudspeaker technology and design principles of audio engineer Steen Duelund (1943 - 2005).
Steen developed do-it-yourself horn designs for full-range single-driver loudspeakers, researched and introduced silk-thread suspension for greater clarity and accuracy for loudspeaker drivers, developed a new crossover theory for seamless driver integration for multi-driver loudspeaker designs (the Duelund Synchronous Crossover), worked with Jensen Capacitors on capacitor, inductor, and resistor development, developed the virtual stack foil principle for capacitors which minimized inductance to deliver higher-fidelity sound quality, collaborated with Gryphon Audio Designs to develop the Gryphon Cantata loudspeakers and the reference standard Gryphon Poseidon loudspeakers, and shared his insights on loudspeaker design in the article The Art Of Building A Loudspeaker To The End.
Frederik and Magnus incorporate Steen’s design insights and the use of natural materials as the bedrock foundation the Duelund Coherent Audio product lines of capacitors, cables, inductors, RCA plugs, and resistors to achieve exceptional clarity, resolution, natural tonal balance, and emotional engagement for unparalleled audio performance when listening to the music you love.
In 2019, Frederik and Magnus acquired the Jensen capacitor and inductor production line, and now Duelund Coherent Audio and Jensen Capacitor are the only Western European manufacturers of paper-in-oil capacitors.
Duelund Coherent Audio is also the original equipment manufacturer for Siemens paper-in-oil capacitor production, and for Balanced Audio Technology's polypropylene and silver capacitor production.
While Frederik's and Magnus' companies, collaborations, and original equipment manufacturer roles continue to grow, the mission focus for Duelund Coherent Audio continues to be you and your audio adventures, and providing you with the highest-performing audio components on Planet Earth so you too can achieve your audio dreams.
Frederik has certainly played an enormous role in achieving my audio dreams, and our "Duelund-Corona 832A Project" has wildly exceeded all of my performance expectations. I am positively giddy with the results.
My goal in this article is to share with you the details of the process we followed for building new crossovers, as well as a series of serendipitous events that resulted in such stellar performance, so that you too might be able to use this article for inspiration and as a template for pursuing your own crossovers project adventures.
Vintage Altec Corona 832A loudspeaker with an adjustable Duelund CAST crossover.
Here's our project in a nutshell: I have a beautiful vintage pair of Altec Corona 832A loudspeakers going on seventy years old that I positively adore. The Coronas are early "art" loudspeakers with cabinets built by Glenn of California in the California Modernist style that was popular in the architecture and furniture design movements of the 1940s and 1950s. Our goal was to upgrade the stock Altec N800E crossovers with the highest-fidelity crossovers possible to release the full performance potential of the Corona 832A loudspeakers.
It turned out that the project was also propelled along by a series of serendipitous suggestions in choosing a crossover circuit (courtesy of Yazaki-san), modifying the crossover circuit (courtesy of Pete Riggle), choosing components for the crossover circuit (courtesy of Frederik Carøe), and adding in some vintage Japanese audio culture ideas (courtesy of Yazaki-san), which led to extraordinary results that let the full magic that Duelund CAST components are capable of be fully realized.
The resultant Duelund CAST crossovers exhibited state-of-the-art performance in terms of clarity, resolution, natural tonal balance, emotional engagement, and on-the-fly crossover adjustability that elevated the performance of my vintage Altec Corona loudspeakers by an astonishing amount.
Duelund-Corona 832A Project crossover for Altec Corona 832A loudspeakers.
If you've been following along with the Duelund Coherent Audio series of articles I've written here at Positive Feedback (you can see the full list in the archives - scroll down to the Duelund section), you know Frederik and I have been collaborating on crossover adventures since 2013, so for well over a decade now, and the Duelund-Corona 832A Project is our third crossover collaboration.
I would like to say a huge “Thank you!” to Frederik for collaborating with me on these crossover projects, as they have been some of the most enjoyable, illuminating, and performance enhancing experiences of my audio and music life.
Our first two crossover projects were for the Tannoy Westminster Royal SE loudspeakers in 2013 (Part 1, Part 2, and Part 3), and then for Conductor Leopold Stokowski’s custom vintage Altec loudspeakers in 2019 (HERE).
What has become apparent to me during our crossover adventures is that crossovers really ought to be considered as important stand-alone "components" in their own right, rather than just viewed as having a subordinate and unconsidered role within a loudspeaker system.
The importance of upgrading crossovers as “components” like I would do for source or amplification components has turned out to be an incredibly important part of my approach to elevating audio system performance to the next level.
Duelund CAST pure copper capacitors.
There is easily as great a magnitude of improvement in audio performance by upgrading stock loudspeaker crossover circuits with Duelund CAST components as there is going from an inexpensive off-the-rack integrated amplifier to an artisanal-level vacuum tube amplifier.
Duelund CAST components in the crossover circuits turns out to be a very big deal when it comes to achieving the ultimate performance potential of loudspeakers.
A note about cost: The cost of building a pair of Duelund crossovers can vary from relatively affordable to uber-expensive depending on the complexity of the crossover circuit, the choice of components from the CAST, VSF Black, or JDM product lines Duelund offers, and whether one chooses pure copper, tinned-copper, or pure silver conductors.
For example, if you take a look at the retail prices on the Anderson Audio website, the Duelund CAST product line components for this project would be $2778 USD for the four copper 10.5 uF CAST capacitors, plus $2668 USD for the four copper 3.5 mH CAST inductors, for a total of $5446 USD (excluding VAT).
If one chose the Duelund JDM copper product line components, the cost would be $1326 USD for four 10.5 uF JDM capacitors, plus $2189 USD for four 3.5 mH JDM inductors, for a total of $3515 USD.
One could further conserve costs by going with the Duelund JDM metalized polypropylene components, where a 10uF JDM metalized polypropylene 250v potted capacitor costs approximately $44 USD, for example.
Duelund CAST Sn-Cu capacitor with coffee cup for scale.
I have found that the magnitude of improvement per dollar spent on crossovers is typically much greater than one would realize through upgrading source or amplification components by the same amount.
In that sense the Duelund Coherent Audio components can be considered to be a very good value, if not a bargain, for the amount of performance gained for the amount of dollars spent.
For example, whether Duelund components for a crossover project total $3515 (JDM), or $5446 (CAST), or whatever, depending on the Duelund components you choose, those dollars spent on crossovers typically yield a much greater magnitude of improvement to performance than would be realized by spending that same amount on upgrading sources or amplifiers. That’s my observation.
Duelund CAST pure silver capacitors.
Perhaps the most gratifying aspect of building a pair of Duelund CAST crossovers is that they allow you to hear how high the true performance level of your loudspeakers is, which is likely much higher than you have ever realized.
Also, an additional benefit I've experienced with the Duelund CAST crossovers was the shock and awe effects of experiencing that the audio components upstream of the loudspeakers were actually much higher performing than I realized.
I would posit that a fair amount of what we have thought were sound quality limitations with our components were more likely just the stock crossovers suppressing the full performance level of our components.
The double bonus to upgrading crossovers is that the loudspeakers will sound way better, and it's likely that the upstream components will too. That's what happened with this project. More about this in a moment.
Stock crossovers are built to a cost point that allows loudspeakers to be sold at reasonable prices, and typically stock crossovers tend to be to the lower-to-middling-fidelity side of the high-fidelity spectrum.
As a result, one never gets an idea of what the loudspeakers are truly capable of performance-wise, compared to what can be achieved with ultra-fi crossovers like the Duelund CAST crossovers.
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