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       About me ...
From the cover of The Audio Adventure magazine, February 1996.
Read the whole article here.


  • When Jan Didden visited in October 2010 he interviewed me about my involvement with audio before, during and after my 37 year career in R&D of Microwave and RF Test Equipment at Hewlett Packard Co. (now Agilent) in California. The interview was published in the Juli 2011 issue of AudioXpress magazine.

  • At AXPONA-Atlanta in 2011 I was interviewed by vimeo about ORION-4.

  • At the ALMA International Winter Symposium in 2014 I was honored with "The Titanium Driver Award", which recognizes a specific technical contribution, accomplishment, or expertise in the loudspeaker industry. The award was presented by Laurie Fincham (KEF, Harman Group, THX). I had written a letter to him in 1974 with questions about loudspeaker design at KEF and explained what we had observed at HP in our DIY loudspeaker design efforts. An extensive air mail correspondence, personal meetings and a lifelong friendship followed.

  • At the REPRODUCED SOUND 2015 Conference of the Institute of Acoustics in the UK I received the "Peter Barnett Memorial Award"; "For technical excellence, practical advancement and education in the fields of electro-acoustics and speech intelligibility" -. Photos & Sound

  • The UK audio magazine Hi-Fi News & Record Review reports on me and my work for rendering sound scenes in their March 2016 issue:
    hfn-cover.jpg (151954 bytes) hfn-page1.jpg (382556 bytes) hfn-page2.jpg (394450 bytes) hfn-page3.jpg (412955 bytes) hfn-page4.jpg (413150 bytes)

  • published an obituary on Siegfried Linkwitzī work and achievements (September 2019 issue).

  • Reminescenses on Siegfried Linkwitz 
    by Floyd Toole, John Vanderkooy and Laurie Fincham


Siegfried Linkwitz was a rare combination of music lover who could hear analytically, and an engineer who could design, measure and interpret the performance of loudspeakers. 
He contributed much more than his well known crossover topology. 
He created novel loudspeaker designs and candidly reported on their performance in objective and subjective terms. He respected the scientific method. His insights and observations will be missed. RIP

Floyd Toole


Some reminiscences of Siegfried Linkwitz from John Vanderkooy:

Over the many years that my wife and I have known Siegfried and his wife, I have witnessed a dedicated audiophile and researcher who was always bent on sharing his work. We were warmly invited to his home on several occasions, and I remember that we could always look forward to an evening of scientific stimulation, engaging conversation, some of his favorite music, and an excellent meal. Eike made sure that there was always a continental flavor. We did talk about our families, how they matured over the years, grandchildren and so on, but I must say we never left audio topics for long.

The loudspeakers and their design was important, but it was even more significant that we experience the results of some of his handiwork. Siegfried never wanted to commercialize his designs, but gave away the secrets to anyone who showed real interest. I was always impressed by how well he could measure and assess the loudspeaker designs with cunning and mostly homebuilt equipment. Since his recorded music was often made with two simple coincident microphones, requiring a median plane seat, each of us would take the optimum listening seat in turn.

It is without doubt that Siegfried was the main force behind the thinking that if we took care of certain aspects of the reproducing acoustic system, the human mind would contribute its share of cognitive tricks to give wonderful renditions. Recent trends to study the hearing process and the effect of music on the mind show that Siegfried was ahead of his time. I hope that others will take up the challenges to do meaningful things in these simpler aspects of music reproduction. The audio community will sorely miss him.


Laurie Fincham:

Siegfried Linkwitz, my friend and audio confidante for over 40 years, died on September 10th, 2018. after a long illness.

He was born in Bad Oeynhausen in Germany in 1935 and received his degree in Electrical Engineering from the Technical University in Darmstadt. He came to the US in the early 1960ís, was hired by HP and spent the whole of his professional career, 37 years, in their Microwave Lab. He became an expert on RF measurement methods and managed the design of the HP 8566 Spectrum Analyzer. This was so expensive, and HP sold so many of them that he was awarded a plaque that called him the "Billion Dollar Man".

It was in this lab that he shared a common interest in audio with some of his fellow engineers. They made hi-fi components in their spare time including loudspeakers. Siegfried is perhaps best known in the audio community for the Linkwitz-Riley crossover filter. This ironic for, as he remarked, within HP it was known as the Riley-Linkwitz filter for the simple reason it was invented by his friend Russ Riley.

Siegfried told me that Russ never minded about the naming because for him it was the invention not the credit that mattered. For Siegfried on the other hand it was important to publish and share it with others. He did, and while I was working for KEF Electronics in England we saw his paper in the AES Journal and decided to use this filter topology in our new speaker system, the KEF 105. We called it the Linkwitz-Riley filter and the name stuck.

Siegfried was the ultimate polymath. He did so many things and all so well. Wind- surfer, engineer, scientist, philosopher, music lover, hobbyist and especially communicator. Whether it was in person, on paper or in social media Siegfried was always thought provoking but presented his ideas with a flair that both charmed and informed expert and tyro alike.

In his lifetime Siegfried has become one of the most celebrated loudspeaker experts. All this from someone who didnít join the loudspeaker industry until after he had retired! For the rest of us it takes a lifetime- even if we start young. Talk about a gifted amateur!

Siegfried has been an inspiration to professional and loudspeaker amateurs for as long as I can remember. And he made thousands of friends around the world through his website and DIY speaker kits. He has influenced me, and countless others, with his provoking ideas, practical advice, and DIY projects. His philosophical musings and observations about how we perceive sound and of course why we should all use dipole loudspeakers to listen to stereo, persist to this day.

Siegfried was still learning, still teaching and still sharing his thoughts on sound and his love of music to the end. I shall miss his stimulating conversations and musical presentations..

His lifeís work is our enduring legacy. His website, www.linkwitzlab.com will continue under the leadership of one of his friends, Dr. Frank Brenner. He is survived by Eike, his wife of 57 years, and his children Monika and Andreas and three grand-children Julia, Anja and Danielle.



A little bit about work, fun and life ...

Work / Fun Hewlett-Packard Co., Palo Alto and Santa Rosa, California, '61-'98
(R&D Design Engineer, Project Mgr., Section Mgr., Senior Engineer)
Siemens, Zentrallabor, Muenchen, Germany, '61
Telefunken, Hannover, Germany, '57 
Major Projects / Designs 8566 Microwave Spectrum Analyzer, 100Hz - 22GHz, '78
8554 RF Spectrum Analyzer
8405 RF Vector Voltmeter
8546 EMC Analyzer
85650 Quasi-Peak Adapter
85685 RF Preselector
EMC Standards Development ANSI C63.1 
IEC/CISPR SC/A, Publication 16
Education Ongoing ...
Stanford University, EE, '62-'64
TH Darmstadt, Germany, Dipl. Ing. Elektrotechnik, '55-'61
Abitur, Kant Gymnasium, Bad Oeynhausen, '55
Radio Amateur License DJ1SX (diy 2-m rig), '51
Audio Fun / Work Linkwitz Lab, consulting/sharing, '99-present
Phoenix  3/2000 *** Thor  7/2001 *** Orion  9/2002 *** Pluto  4/2005 *** Pluto+ 7/2006 *** Orion++ 1/2007 *** Pluto2  5/2008 *** Orion3  7/2010 *** Orion4  4/2011 *** LX521  10/2012 *** LXmini  6/2014 ***  LXstudio  5/2015 ***  LX521.4  6/2015  ***  LXmini+2  4/2016  *** LX521.5-ASP  6/2016  ***  ASP.4  12/2016  ***
Audio Artistry, VP of Engineering, '94-'99
(Vivaldi, Dvorak, Beethoven, - Elite, - Grand Loudspeaker Systems)
G-Jobs with colleagues at Hewlett-Packard, '62-'94
(FM tuners, stereo decoders, pre- and power amplifiers, equalization of commercial speakers & headphones, passive crossover box speakers, active crossover box and open baffle speakers)
Fun Reading, digital photography, listening to recorded music, live music, audio design, recording, traveling, windsurfing, downhill skiing, hiking,    
Home front Born '35, Bad Oeynhausen, Germany
Father: Oeffentlich bestellter Vermessungsingenieur (surveyor); Mother: School teacher's daughter; Brother: 8 years older
WW2 and post-war Germany from a young person's perspective, '39-'48
Lutheran Confirmation (but serious doubts about religion), '49 
Married, '61 (my wife's assessment of a loudspeaker's sound and appearance is important to me)  
Working at HP in California for a 2 year cultural experience, '61
Involvement with New Age groups ('63+) and challenging R&D work at HP resulted in permanent stay in the US  
Daughter in '62; Son in '65; Granddaughters, '99, '04, '05
Spiritual search  Jesus as Teacher discussion groups - Sequoia Seminar - LSD - Creative Initiative - Beyond War - Eckhart Tolle - Adyashanti - Tony Parsons - ThetaHealing - My conversations with Fitz - Mooji -
Recent reading Noam Chomsky,  Who Rules the World ?, (2016, Afterword 2017)
Akerlof & Shiller,  Phishing For Phools - The economics of manipulation and deception (2015) 
Mooji,  Vaster Than Sky, Greater Than Space - What you are before you became (2016)


Siegfried Linkwitz' Life Story (by Eike Linkwitz, 2021)


Siegfried was born on Nov. 23,1935 in Bad Oeynhausen, a small spa town in Germany, the second son of a civil engineer and his wife. Part of his childhood was spent during WWII, running to air raid shelters with his mother. Siegfried's father and older brother were soldiers in the war. Young Siegfried knew all the airplanes overhead.

At one point, all inhabitants of his hometown were forced to evacuate within 24 hours because the British seized the town as a headquarter. 

When WWII ended, the extended Linkwitz family was divided between East and West Germany. In his spare time, Siegfried and other youngsters climbed amidst the rubble of destroyed WWII buildings to look for valuable materials. He became fascinated with anything having to do with radio-technology. He built himself a short-wave radio to send secret messages and had to wait for his 16th B-Day to pass a Ham operator exam. Since Germany was so isolated, he and high school friends started biking and later hitch-hiking during vacations to France, Italy, Switzerland. He talked to people about the war, sharing about the hardships, and found common ground with strangers -- a very revealing and bonding experience. 

After high school, he studied at the Technical University (TH) in Darmstadt, earning his degree in Electrical Engineering. He also met Eike, his later wife in Darmstadt, a senior in high school. His new love left for college in Munich, and he visited her on many weekends, only hitch-hiking: a round-trip of 600 miles. Luckily, he could stay overnights in Munich at his older brother, wife, and nephew. The courtship via hitch-hiking stretched over 2 years. One day Siegfried added up all the trip miles and discovered, he had circled the Earth once. 

Prior to completing his EE degree, Siegfried heard that Hewlett-Packard was open to hire young foreign engineers. After applying and being interviewed, he was offered a job.  Three days after the young couple's wedding in early August 1961, Siegfried flew to California. Eike had to wait for her visa, which was stalled by political tensions. Mid-August 1961, Berlin was barricaded, the Wall was built, and foreign travel was halted.  

At first Eike and Siegfried wanted to stay in Ca. for 2 or 3 years to glean the cultural experience, but soon it became clear, that the rich opportunities and experiences in California had a huge impact on them.  

A successful engineer at HP in Palo Alto, Siegfried was Project Manager, later in Santa Rosa Section Manager of big research and design projects in the Microwave Lab, with the 8566 Spectrum Analyzer the crown of his 37year career at HP. He represented HP in major ongoing education and for the US in international EMC standards development, like ANSI, CISPR, etc., which included travel throughout the world with Eike often at his side. 

In 1962, Siegfried and Eikeís first child, Monika, was born, followed 3 years later by Andreas. Family life was rich and fulfilling with friends, camping, sailing, skiing, windsurfing and trips to Germany to get their bilingual kids closer to all grandparents, aunts, uncles and cousins. 

In the early 60ís a series of evening discussions on the life and teachings of Jesus of Nazareth and their meaning for today, caught Siegfried's and Eike's attention. For more than 20 years, they became very involved with Creative Initiative. Their search for the spiritual life remained central and expanded until today. A still captivating reading is: "Vaster than Sky, Greater than Space...what you are, before you became", by Mooji. 

Throughout 57 years of marriage, Siegfried and Eike focused much free time on classical music, attending the San Francisco Symphony for 50 years. Siegfried' s beloved loudspeaker design hobby, never asleep, emerged more than ever, as retirement from HP approached. Siegfried concentrated on an audio internet business, www.linkwitzlab.com and published everything he had learned about speaker designs. Already a name in the audio world, with the Linkwitz-Riley filter, and having published papers in Wireless World in the 70ís and for the AES, his new venture was a success. Since its inception in 2001, Siegfried has filled hundreds of orders from 56 countries for his precise construction plans of different speaker designs. And now www.linkwitzlab.com will continue under new leadership of Frank Brenner.



B E I N G  A L I V E 





SL:  It occurred to me that the Association Model of Perception is as important to understanding life and living, as is Einstein's (e = mc2) to understanding physics.

The AMP describes how we take in the outside Reality and deduce from our perspective a Subjective Reality, which has Meaning to us in context of previous observations of Reality. We associate current input data with stored memory data, many of which are hard to access directly, and we respond accordingly: physically, mentally, emotionally and intuitively.


=======  to respond without resistance  =======






Biography for invited talk "My Search for the Ideal Stereo Loudspeaker", 
AES 51st Conference on Loudspeakers and Headphones, Helsinki, 2013

Siegfried Linkwitz

April 2013


Since 1999 I have been adding information to the LINKWITZ LAB website to educate about loudspeaker design, sound reproduction and recording. I provide detailed plans for DIY construction of state-of-the-art dipole and monopole loudspeakers using active electronics. The speakers are optimized for operation in reverberant domestic spaces.

After retirement from Hewlett-Packard Co. (now Agilent) in 1998 I continued to pursue my life-long interests in audio, having designed between 1994 and 1999 a line of dipole loudspeakers with moving coil drive units for Audio Artistry. While at HP I developed the "Linkwitz Transform" circuit and earlier, in 1975, the "Linkwitz-Riley Crossover" filters out of a shared audio hobby with Russ Riley.

I worked for 37 years in Research & Development at HP, on state-of-the-art electronic test equipment, such as microwave spectrum analyzers, network analyzers and EMI receivers. I traveled, teaching HP Seminars on test and measurement in the frequency range from 10 kHz to 20 GHz. During my last 18 years at HP I also participated in national and international standards development for Electromagnetic Compatibility Test Instrumentation through ANSI and IEC/CISPR 16.

I came to the US in 1961 with my wife Eike, after having received the Diplom Ingenieur degree in Electrical Engineering from Darmstadt Technical University in Germany. I continued my education with postgraduate studies at Stanford University while working at HP in Palo Alto. We have a daughter, a son and three grandchildren.








We are all inventors,
each sailing out on a voyage of discovery,
guided each by a private chart, of which there is no duplicate.
The world is all gates, all opportunities.

Ralph Waldo Emerson



Siegfried Linkwitz - Eike L. (Traut)
Monika Balsamo (Linkwitz) - Ron B. - Julia B. (18)
Andreas Linkwitz - Susan L. (Snyder) - Anja L. (13) - Danielle L. (11)
June 2017


I feel blessed, having been given a life
to contribute to understanding, consciousness and joy.


Burning Amp - 2017

"Baffle diffraction versus neutral sound dispersion"


* SL*
- Aggressive Prostate Cancer (2002) - 
- Stage 4 PrC (2016) -
- Hospice Care (2018) -










What you hear is not the air pressure variation in itself 
but what has drawn your attention
in the streams of superimposed air pressure variations 
at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space
Have they been recorded and rendered sensibly?

Last revised: 02/15/2023   -  © 1999-2019 LINKWITZ LAB, All Rights Reserved