Obituary: Chris N. Strahm (1956–2017)

Chris N. Strahm, co-founder of LinearX Corporation, was the sole inventor and designer of some of the most important design and measurement tools used by audio engineers right around the world, including LEAP, LMS, the LT360 measurement turntable, the pcRTA, the RTAjnr and the ATI Paragon mix console. A polymath whose skills encompassed electronics, mechanics, acoustics, high-level coding, robotics, technical writing and production engineering, he was universally acclaimed as ‘brilliant’ in every one of these fields.

Chris Norman Strahm was born Norman Christ Strahm on November 20th, 1956 in McMinnville, Oregon to John and Alice (Hillig) Strahm. His father died when Chris was only seven, and he took on the responsibilities of being ‘the man of the house’ which infused in him a sense of responsibility that would inform the decisions he made for the rest of his life.

Chris attended McMinnville High School and after graduating in 1975 went straight to Oregon State University where in 1978 he was awarded a BSc with a major in electrical engineering and a minor in computer science. A keen guitarist, Chris formed a band called ‘Archer’ in which he played to help make ends meet.

After graduation he first worked at Hewlett Packard before signing on at NorthWest Sound, a professional sound company located in Portland, Oregon which was contracted to provide stage equipment for bands including The Eagles, Fleetwood Mac, and Chicago. There he worked under the tutelage of famous product development engineer Cal Perkins (Marantz, JBL, BiAmp, Mackie and Loud). He and Perkins became life-long friends. ‘Chris was undoubtedly one of the most brilliant people I have had the privilege of knowing,’ says Perkins. ‘He definitely was the hardest-working person I have ever met. There was no off switch.’

It was while he was working at NW Sound that Chris started his own company, CNS Electronics, so he could work on his first product, the Loudspeaker Enclosure Analysis Program, now known as LEAP. At the time of its release LEAP was revolutionary because it added additional parameters to the accepted Thiele-Small parameters which were the standard for speaker enclosure design. Strahm’s enhancements gave users the ability to accurately model speaker array systems, such as those used and sold by NW Sound. It was also entirely Chris’ own work. Chris once told Alan Shaw, of Harbeth Loudspeakers, that there were a million lines of code in LEAP. ‘That is a huge intellectual achievement for one individual,’ says Shaw.

In November 1986 Chris was invited to present a paper at the 81st Audio Engineering Society Convention, which he did [A Complete Analysis of Single and Multiple Loudspeaker Enclosures, Paper #2419]. Although the paper was accurate, it pointed out many of the errors made in prior modelling and analysis papers, one of whose authors was in the audience and took violent vocal exception to both Strahm himself and the content of his paper. As Cal Perkins remembers it: ‘Unfortunately for the audio community, (Chris) was verbally attacked in the author’s lounge by a member educated ‘way beyond his intelligence and sadly, because of this, he withdrew from any further AES activities.’

Chris Strahm with his first wife, Vickie [Sheppard], and their twin daughters, Nicole and Michelle, picured at LinearX’s headquarters in Tualatin, Oregon, in December 1999.

Curiously enough, it was this paper that made Vance Dickason (founder of Speaker Research Associates, author of the Loudspeaker Design Cookbook and currently editor of the loudspeaker industry publication Voice Coil), aware of Chris’s activities. ‘[His paper] was so advanced over the current Thiele-Small standard model that I was, in the vernacular of the day, blown away,’ says Dickason. ‘When I found out Chris lived in the same city as me, I contacted him and we became immediate friends.’

Soon after, NW Sound was purchased by Maryland Sound Inc and Chris and Richard Irwin (one of the two founders of NW Sound) left the company and joined forces with Larry Droppa to found ATI-Audio Teknology, Inc. with the aim of building a unique live mixing console. Their first hire at the new company was Vickie Sheppard, who would not only become the office manager for ATI-Audio, but also Chris’s first wife and the mother of their two children. Sheppard remembers her first meeting with Chris very clearly. ‘The first words he said to me at the interview were: “You are an incredibly attractive woman,” so I’m thinking, score… this is going to be easy! It turned out it was, and I started the next week as the company’s “Accounting/Administrative Coordinator”. Chris had let me pick my own title.’

Chris was so busy at ATI-Audio developing what would become the Paragon Live Mixing console that he had no time to work on promoting and selling his LEAP software, so he offered to pay Sheppard a commission on every program she could sell. She recalls that it was very easy to make sales, because Car Stereo Review magazine had just published a rave review of the program and so LEAP was ‘flying off the shelves’. The Paragon mixing console also turned out to be highly successful, and was nominated for a Technology Award in Mix Magazine.

Whilst working at ATI-Audio Strahm was also working on a project that would earn him one of his many patents, a ‘transformerless transformer’ he called an ‘electroformer’. Perkins says it was the first truly floating and balanced output stage that behaved like an output transformer. He clearly recalls his first sighting of Chris’ new invention: ‘One evening Chris brought to me a little vero board covered with TO-92 transistors for me to evaluate and witness for a patent,’ he said. ‘Needless to say it worked far better than anything else that I had seen to date.’ Chris was granted a US patent (#4979218A) for this invention. His other patents included for one for a high-voltage low-distortion input protection current limiter (#6970337) and one for an audio signal energy level detector for use with audio signal processing (#5170437).

But it was Strahm’s development of the first low-cost, high-precision loudspeaker measurement system, his Loudspeaker Measurement System—now better-known simply as ‘LMS’—which was to make his name a byword in the loudspeaker design community. LMS was comprised of a custom computer soundcard, a calibrated instrumentation microphone and custom software, all designed and developed entirely by Strahm himself.

Chis not only designed and manufactured his own equipment, he also produced the User Manuals himself, acting as author, editor, typographer and layout artist.

The User Manual for LMS (Win32 Release 4.1) the front cover of which is pictured at right, was 368 pages long.

As with all his manuals, it was not only a ‘User Manual’ but also a text book on loud-speaker measurement. Strahm’s customers quickly found it was worth taking the time to read his manuals from cover to cover.

According to Dickason, who worked with him at ATI-Audio for two years, Chris was one of the best hardware and software engineers he’d had the privilege to know. ‘People who knew Chris invariably applied the words “brilliant” and “genius” to his analytic ability and his engineering acumen,’ he said. ‘LMS was probably one of the most-used analysers in the industry at that time, selling more than 4,000 to loudspeaker companies and engineers worldwide.’

For Mark Gander, of JBL, the Paragon mixing console was Chris’s masterwork. ‘With a unique circuit topology and an advanced layout for its time, it became an industry benchmark for performance and innovation,’ he said. A 100-channel version of the ATI Paragon was installed in the Grand Ole Opry.

In 1993, shortly after LMS was developed, ATI-Audio ran into money problems, partly caused by the cancellation of a single order for eight ATI Paragon mixing consoles by one of the US’s largest touring companies. Strahm left ATI-Audio, retaining the licensing rights to LEAP and LMS, and asked Vickie Sheppard to join him in establishing LinearX Systems, Inc. to build and market LEAP and LMS, as well as another analyser he’d been working on, the pcRTA. ‘We pooled our funds to establish the business, called our distributors to let them know we were still in business and several of them placed large stocking orders so we were off to the races again,’ recalls Vickie. ‘Chris went straight to work on the pcRTA, which was a high-resolution real-time analyser that simultaneously processed inputs from four separate microphones and calculated spatial averages. The pcRTA was developed for THX, as they were scrambling for a way to tune and test the theatres they certified. We worked directly with Tom Holman, the creator of THX. He invited us to visit him at George Lucas’ ‘SkyWalker Ranch’ in California. We got the grand tour at the same time that Robert Redford was delivering the tapes for the movie, “A River Runs Through It” so all in all, it was quite thrilling.’

he pcRTA was certified by both THX and Dolby for use in tuning movie theatres and was later adopted as the official analyser for use by the International Auto Sound Challenge Association (IASCA).

By now LEAP and LMS had become very well-known and respected tools used by all sections of the speaker industry, particularly the professional audio and hi-fi industries, but it was the car audio industry that was LinearX’s largest and most profitable market, so Chris created a much smaller and less complicated PC-based RTA, called the RTA Jr, aimed specifically for the car audio sector. The RTA Jr put LinearX on a very stable financial footing, so Chris proposed to Vickie and the two married in 1994. Chris boasted that after he and Vickie established the company, its sales reached the $US1,000,000 milestone in just four years and had continued at a growth rate of 100–300 per cent per year in the years following. ‘The company has been profitable through every quarter since its inception,’ he wrote on LinearX’s website. ‘All growth has been funded solely through the profits of the business.’

LinearX continued its exponential success, expanding into China, where LMS was mandated for use by the Chinese government, which allowed Strahm to produce what many claim is his greatest achievement, a software program for designing loudspeaker crossovers (and other filters, both analogue and digital), called FilterShop. ‘FilterShop has become an essential tool for audio designers worldwide,’ says Gander.

Pictured Above: While working on the LX500, Strahm realised that a custom low-pass filter would be required if the LX500 was to be able to test Class-D amplifiers correctly, so he developed the LF280 Precision Amplifier Filter/Attenuator, which went into production to become the lowest-cost, highest-performance filter of its type, yet he sold them for less than half theprice of competitive filters sold by Audio Precision and Prism Sound.

Eric Guarin, who was a senior engineer at Alpine of America when LEAP was released, remembers: ‘Back in the day, there were various speaker modelling programs, but they were all still vague models based strictly on Thiele and Small—and Dick Small would have been the first one to caution that those parameters were for small signals and to be used with caution. When LEAP came out, it was like a bolt of lightning. Hey! I can import real data for response and impedance? So I can really do a true crossover simulation? Incredible! The later expansion into large-signal parameters was another giant “LEAP” forward as well.’

Chris and Vickie’s twin daughters Nicole and Michelle, were born in 1998 and Vickie stopped working at LinearX so she could stay home with the children. Six years later, in 2004, the two divorced, ending their nearly 20-year relationship. Strahm continued running LinearX and started work on a new electro-acoustic analyser, the LX500, that in addition to loudspeaker measurements, could also be used to test electronic components, including amplifiers, DACs and would be released in direct competition with the two leaders in this industry, Audio Precision and Prism Sound.

Work on the new LX500, which used USB to connect to the host computer, was essential, because it had to replace LMS, which was built on an ISA card that didn’t fit into modern computers, which required owners and new buyers to use ‘legacy’ computers with ISA slots. He discussed issues involving transitioning from ISA to USB with James Reedy of Harman International. ‘We’d talked at some length on a couple of occasions about getting LMS moved off of the old ISA cards and into something USB based,’ says Reedy. ‘Early in my career I spent an awful lot of time using LEAP—and to a lesser extent LMS—in my work at Harman. At the time they were “the” tools to have.’

While working on the LX500, Strahm realised that a custom low-pass filter would be required if the LX500 was to be able to test Class-D amplifiers correctly, so he developed the LF280 Precision Amplifier Filter/Attenuator, which went into production to become the lowest-cost, highest-performance filter of its type, yet he priced and sold it for less than half the cost of competitive filters sold by Audio Precision and Prism Sound. Dr Richard Cabot, the founder of Audio Precision, was well aware of Strahm’s work. ‘Chris was a brilliant engineer who easily transcended the boundaries of electrical, mechanical, acoustical and software engineering,’ he says.

‘LEAP, FilterShop, the LT360 turntable and many others … are the work of Chris Strahm alone, all the way down to the packaging and manuals. Few individuals have the breadth of skill required to develop these, and fewer still could do so to the high standards he always maintained.’

In 2008, Chris married Susan (Susie) Munro and the two moved LinearX from what had been its long-term home in Tualatin, Oregon, where it had a 10,000 sq ft facility to a very small factory in Battle Ground, Washington. Strahm continued to be devoted to his twin daughters, with Vickie recalling: ‘He often told me that the twins were the best gift I had ever given him. He loved spending time with them, taking them on walks and watching their favourite shows, such as VeggieTales and Teletubbies, with them. We enjoyed countless family get-togethers with his mom and his younger brother and his wife.’ Chris’ daughter, Michelle, wrote on her father’s condolence page: ‘Most of the happiest memories in my life involve you. You would spend so much time with Nicole and me when we were younger. Nearly every night you would take time out of your work schedule to read to us a story out of our Calvin and Hobbes collection. On Fridays we would sit in front of our TV with popcorn and ice cream and watch movies with you.’

Following his divorce, Strahm continued to be devoted to his twin daughters, Nicole and Michelle with Vickie recalling: ‘He often told me that the twins were the best gift I had ever given him. He loved spending time with them, taking them on walks and watching their favourite shows, such as VeggieTales and Teletubbies, with them.’ 

The move to Battle Ground seemed prophetic, because Strahm was battling to get the LX500 into production, and due to his policy of not raising the prices of his products—even to match inflation— plus the fact that parts were no longer available to build LMS which, along with the LT360 turntable, was one of his biggest-selling products, meant that LinearX’s sales were dropping calamitously, so there was no money to buy parts to complete the LX500, or even pay wages… though by this time LinearX had only three employees... including Chris and Susie. Susie says: ‘Chris always thought of his customers. People would tell him to raise the prices for his products but he’d always refuse, saying “No, I want to give my customers products that are not only very high quality but also at a price they can afford.”


In 2017, Chris Strahm was posthumously awarded a 'Beryllium Driver Award, for Lifetime Achievement, by the American Loudspeaker Manufacturer's Association (ALMA International). It was presented to Susie Strahm by Vance Dickason (pictured above).

Sadly, just as Chris seemed to be nearing a break-though in the production of the LX500, a product that would have turned his company’s fortunes around, he very suddenly and unexpectedly died of acute liver failure.

 Chris’s first wife, Vickie, says she and Chris’s daughters and his brother Ernie only found out the night before his death that he’d been rushed to hospital. ‘Ironically, the girls and I were just finishing up Thanksgiving dinner at Chris’s brother Ernie’s house when we received the news that Chris was in a coma and that he wasn’t expected to come out of it.’
Chris is survived by his wife, Susan, of Battle Ground, Washington; twin daughters Nicole and Michelle Strahm of Tualatin, Oregon; stepsons Brad and Joe Munro; step grandson Logan Munro; brother Ernie (Lori) Strahm of Carlton, Oregon, and former wife Vickie Sheppard of Tualatin, Oregon.

Strahm was preceded in death by his father John in 1963, and by his mother Alice in March 2016. #  By Greg Borrowman, with Vickie Sheppard.