Obituary of Mahlon Daniel Burkhard (Chairman of the Board of Directors, HEAD acoustics Inc.)

05. October 2021

Mahlon Daniel Burkhard passed into the great unknown Thursday, Aug. 26, 2021. He passed at Buckingham’s Choice, Adamstown, Maryland, at the age of 98.

Mahlon and his wife Charlotte raised four sons: Ronald, Douglas, John and David. They lived in a wide variety of places during their 73-year marriage, including Nebraska, Pennsylvania, Maryland, Illinois, Connecticut and West Virginia, before finally settling in Adamstown.

Mahlon was born in Seward, Nebraska, Jan. 14, 1923, to Noah and Iva Burkhard. The oldest of three siblings, he lived in Seward until joining the U.S. Navy in 1943. He served in the Pacific Fleet during World War II, piloting landing crafts that delivered U.S. Marines to the beaches of Iwo Jima and Okinawa. In 2020 he recounted to Wade Bray that he was in a landing craft at a distance of less than 1000 feet from the battleship U.S.S. Missouri when it fired its 16-inch guns directly over his vessel. He said he could feel the heat. He had partial hearing loss, and distortion in one ear the rest of his life, which he attributed to that event. It did not dissuade him from a lifetime in acoustics.

During this time he met his future wife, Charlotte, a San Diego, California, transplant, and they were married in 1945 just before the end of the war.

Following his active military duty, Mahlon finished his undergraduate degree at Nebraska Wesleyan University, and then secured an advanced degree from Pennsylvania State University in the field of acoustics. He began his long professional career at the National Bureau of Standards, where he helped establish the first standards for hearing aids. Then he became supervisor of the acoustics design section in the physics research department at Armour Research Foundation of Illinois Institute of Technology, Chicago. He next moved into private industry as Director of Research at Industrial Research Products, where he headed teams developing and commercializing the KEMAR manikin (Knowles Electronic Manikin for Acoustic Research, the first head and torso simulator designed for acoustic research), a line of digital audio signal delay products for use in sound amplification at outdoor venues, and multiple studies of electret materials and processes for use in electret condenser microphones.

KEMAR was introduced to the research community and hearing-aid manufacturers in 1972 and was officially introduced in the spring of 1976 at conferences in Zurich and Washington D.C.

David Preves relates: My first meeting with Mahlon was during the important manikin measurements conference that he organized following the introduction of KEMAR.

 I still treasure and refer to the green book Proceedings of that meeting. At the time, use of KEMAR was the cutting edge for hearing aid measurements. 

Also, I have a lot of good memories of Mahlon’s significant contributions to both ANSI and IEC standards committees that he and I were members of. 

I had a great respect for not only the important things that he did and contributed to our field, but also of him as a person.

Under Mahlon’s direction the spaceborne communication microphones for the NASA Apollo lunar program were built and delivered. The moon mission was unique because, as I understood it (Killion), the Knowles microphones were the first product that went into that mission that was accepted without further reliability testing.  The microphones were so small, four together were smaller than most other microphones, so by wiring four microphones in series/parallel, a short or open circuit in any microphone would cause only an unimportant drop in sensitivity.   

The first development and one of the first applications of Mahlon’s digital signal delay was at the outdoor music pavilion Ravinia, which had a long tunnel beneath the facility. Tests were performed in the tunnel using a speaker and appropriately placed microphones. The first digital delays were timed according to these tests and refined by listening, to assure first arrival of the direct sound for perceived localization.

At this point and place Mahlon’s long collaboration and friendship with acoustician Christopher Jaffe began, as Jaffe was the acoustician of Ravinia, working with its Executive Director Edward Gordon. It was Chris who deployed Mahlon’s first digital delays for multiple loudspeaker rows out into the lawn beginning with the alternating stereo A-B-A-B speakers around the perimeter of the shed roof. Mahlon and Chris resonated with electroacoustic ideas, and soon Jaffe challenged Mahlon to develop a multi-tap non-recursive digital delay as a reverberator extending the natural reflection character in music performance spaces rather than imposing the disjunctive high-density character of recording-studio reverberators. Its first installation (two 48-tap delays, each having a runout time of about 1.7 seconds) was for the 1980 NBC television series “Live from Studio 8H” featuring the New York Philharmonic under Zubin Mehta. From this, Mahlon’s 48- and later 72-tap non-recursive reverberators got the nickname “NBC Delay” at Jaffe Acoustics. Jaffe for very many years used Knowles electret condenser microphones flush-mounted into surfaces such as stage ceiling reflectors in concert spaces, to feed “electronic reflected energy” (ERES) systems and to produce “electronic forestage canopies” where physical ones could not exist -- an early instance being the acoustic renovation of the Oakland Paramount Theater in California.

Through his career, which included serving as Chair (1977 - 1979) of the Engineering Acoustics Technical Committee of the Acoustical Society of America, Mahlon was awarded seven patents, and he made significant impacts in the field of acoustics. Retirement rarely suited him; he attempted it unsuccessfully in the late 1980s almost immediately moving to Connecticut to work with Jaffe on electronic reflected energy systems for the performing arts and become President of Sonic Perceptions, Inc., the new Jaffe Acoustics owned firm which introduced HEAD acoustics binaural technology to North America (Mahlon’s KEMAR work making him a perfect match). It was evident to all of us working with him that his scientific acumen was absolutely accompanied by a wise and effective business management talent. Mahlon retired again in the mid-1990s to become Chairman of the Board of HEAD acoustics, Inc., and finally retired the third time in the mid-2010s to become its Chair Emeritus. Even at age 93 he was regularly flying to Europe for business.

His professional associates knew him best as thoughtful and even tempered — and a leader in his field. His family knew him as an utterly devoted husband, an engaged father, role model and mentor. He was indefatigable in life, always bringing a cheery disposition and just the right wry comment to bring smiles to those around him. He kept alive, daily, the fine art of wearing bow ties.

Mahlon was preceded in death by his wife; parents; brothers Eldred and James; and his son, Douglas. He is survived by his sons; three nephews; two nieces; one granddaughter; four grandsons; two great-granddaughters; and one great-grandson.

All of the undersigned feel very fortunate to have had Mahlon Burkhard in our lives. We will never forget him.

John Burkhard

David Burkhard

Ron Burkhard

Wade Bray

Mead Killion

Gene Ring

David Preves

Klaus Genuit

Michael Stephan

(And with thanks to James West, William Cole and Brigitte Schulte-Fortkamp)