The Early Days of Ohm

Marty Gerstein started Ohm to bring Lincoln Walsh’s technology to market. Marty was the Chief of Engineering at Rectilinear Research in the Bronx. He also hosted a show on public radio where he interviewed people in consumer electronics. During one show, Lincoln Walsh presented his new patented speaker concept and Marty was intrigued. Back at Rectilinear, Marty and his assistant, Jon Dahlquist, tested Walsh’s concept and felt it was worth pursuing. But the owner, Morris Weiner, felt Rectilinear was doing fine with their more conventional line of box speakers and didn’t want to license Walsh’s technology. After all, Julian Hirsch of Stereo Review had reviewed their top-of-the-line, Model III and said they had “never heard better sound reproduction in our home, from any speaker of any size or price.” Marty rounded up some investors including Peter Aczel (later founder of Audio Critic magazine and Fourier Speakers), started Ohm and licensed the Walsh technology.

The Ohm name was chosen because “everyone knows speakers have ohms and will think Ohm is an old company”. (Now we are a 40+ year old company, so it turned out to be true!) Marty quickly designed two box speakers (Ohm B and Ohm C) Link with Peter’s input on sonic balance. These would be the bread & butter speakers while the first full-range Walsh speaker, the Ohm A was developed. Lincoln Walsh did not get to hear the finalized Ohm A, as he died of cancer before the design was completed. The Walsh patent license with Ohm was intended as an assured income stream for his widow.

Tech Hifi, which I started and ran with my partner Sandy Ruby, was a big Rectilinear dealer and we got to know Marty as they developed new models. We agreed to become Ohm dealers when they agreed to help us with the much smaller and less expensive TDC speakers. The Ohm As were good sellers for us even though they needed lots of power. Bob Carver had introduced the Phase Linear 700 with 350 watts per channel into the Ohm A’s 8-ohm load. The combination could really sing but occasionally blew up. It was an easy demonstration to show the sonic advantages of the Walsh design. There were some bumps in the road.

The Ohm As were hard to build and all were practically hand made by Bob Ajay, Marty’s engineering assistant. The Ohm B and Ohm C had tweeters made by Philips that tended to burn out when a low powered amplifier was driven into clipping. But progress was made with the introduction of the Ohm B+, C+,D and E using the new phenolic cone tweeter for the low treble in the two new 3-way models and as the only tweeter in the two smaller models. The development of the smaller Walsh, the Ohm F, offered the Walsh sound without a refrigerator sized speaker – a big benefit. Ohm was making the TDC 4 for Tech Hifi. It was an 8” woofer in an acoustic suspension box with the Philips dome tweeter. Although a 2-way, the tweeters survived in the TDC 4 because of its higher crossover frequency. Tech Hifi prepaid for the TDCs to allow Ohm to use its own cash flow for Ohm brand activities. One day Marty called me and basically said ‘You know the $250,000 Tech Hifi has advanced Ohm? The money is gone paying bills. We are out of inventory and we can’t make the payroll. We are going to close. Sorry…’

I flew to NY and made a deal to buy out Marty and Peter, the two remaining stockholders, on the condition that Marty would stay on as President while I learned the ropes of manufacturing. Both received several times their cash investments rather than a bankruptcy. On analyzing the Ohm operation, it was clear the sales success of the Ohm Fs was causing losses to mount up because the Ohm Fs cost more to make and service than their selling price. With every sale, the loss increased. We instituted a major redesign of the Ohm F. We asked the expanded engineering staff to address only reliability concerns and production efficiency while keeping the same sound. There were many small changes and three major ones:

1. The frame of the driver was strengthened as the heavy magnet assembly on the tall thin legs could shift from an impact during shipping. A small shift would cause a rubbing of the voice coil.

2. The voice coil and bobbin assembly were redesigned with the anodized rectangular aluminum wire flat wound on the outside of an anodized bobbin. The bobbin had been spun to form a trough for the wire and had a flat connection to the titanium cone section. This gave a much stronger assembly with much greater power handling.

3. Ferro-Fluid was added to the voice coil gap and a heatsink was added to the back of the voice coil. Those two changes improved the short term (one-hour) power handing by fourfold and one-second power handling by tenfold. Music is very dynamic; so these were great improvements.

I can now estimate the construction period of an Ohm F driver by observing which of these modifications that Ohm F driver incorporates. This was a real trial by fire for me and I thanked my engineering and business school education. I was commuting between Boston helping Sandy Ruby link run Tech Hifi and Brooklyn learning how to run Ohm. I was on a learning trip and stranded in Brooklyn during the blizzard of 1978 when Marty resigned as president in order to pursue his career in medical electronics. So, I moved in with friends for the blizzard and ended up staying.

Brooklyn days to come in a future blog.

Enjoy & Good Listening!


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John Strohbeen Author

John Strohbeen was the President and Chief Engineer of Ohm Acoustics from 1978-2023.

John Strohbeen

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