I first started working for Sontron Instruments at 17 Arrawatta St. in the Melbourne suburb of Carnegie through a summer Uni vacation job in late 1978. Graham Thirkell, one of Australia's foremost audio engineers, had started Sontron after the closure of his previous iconic company Optronics. I think the name "Sontron" came from a shortened conjunction of "Son of Optronics".
As far as I know, Graham didn't have formal tertiary qualifications but he didn't really need them. He had a very sharp mind and an absolute passion for professional audio. Through Optronics, he had designed and built world class professional audio equipment including mixing desks and his famous 24 track 2 inch audio tape recorders. Unfortunately, Graham was ahead of his time and the Australian market was not large enough to keep Optronics viable in the face of overseas competition.
By the time I got to Sontron, Graham had established a core family business in custom built audio gear and audio consultancy services, along with the Australian distributorship for US based Harrison Audio Consoles. He was a respected and leading audio professional in Australia and had many clients in the professional audio field, including Soundfirm, Allan Eaton Sound Studio, Armstrong Recording Studio and Melbourne radio station 3XY. Graham's wife Katherine ran the business, leaving Graham free reign to run the tech side. Their son Gerrard and daughters Christine and Linda also worked for the company. Other people I worked with were Murray Robinson who had worked for Graham at Optronics (and later married Christine), Graeme Williams, Jeff Palmer, Peter Milevski, Michael Xantzis (?) and Laurence (Laurie) Holk. GT, as we called him, had some core products that helped sustain Sontron, including his famous RIAA equalised stereo disc preamplifier and a SMPTE Time code reader. He and Murray were also still providing support for owners of his previous Optronics gear.
Sontron was starting to build custom S-100 bus based interfaces, including systems for use in audio and video applications. The first project I worked on was to build an S-100 based card to capture video images, designed by Peter Cherney, one of Graham's early tech designers. The card captured coarse monochrome images and was built for a research scientist at Monash University to record the growth of leaves and other flora. Another early project was to design (with Graham's guidance) and build an electronic metronome for Peter Best. Peter wrote soundtracks for many Australian films, including the Barry McKenzie films, End Play, The Picture Show Man, We of the Never Never, Goodbye Paradise, the Crocodile Dundee films and Muriel's Wedding.
A further area of work for me was installation of Harrison equipment that companies had bought through Sontron. One involved installing a 48/32 channel Harrison mixing desk as part of the build of the legendary Paradise recording studios at 70 Judge St Woolloomoolloo in Sydney, owned by then millionaire Billy Field. Billy's family were wealthy graziers and he left no expense spared, so it's no surprise he wanted a Harrison mixing desk. Paradise had a sauna and jacuzzi, a spacious control room and an even more spacious studio including a glass walled live booth. The studio had a clever airconditioning system that used a combination of heating and cooling to precisely maintain the temperature in the studio, and thereby keep the instruments in tune, regardless of traffic in and out of the studio during sessions. The cooling system was run flat out and the air was then heated to the desired temperature for the studio. It was much faster for the system to react to temperature changes by adjusting the heating as opposed to the cooling. The entire studio was built on a floating floor to virtually eliminate rumble from the nearby Bondi Junction railway line.
Billy recorded his hit "Bad Habits" album as the first full recording session at Paradise. I still have an original vinyl pressing, given to me as a promotion from Radio 3XY at the time of release that has never been played. Many famous Australian artists recorded at Paradise. Iva Davies and Icehouse started their career there as Flowers. Cold Chisel recorded their third album "East" with producer Mark Opitz at Paradise and also INXS, again with Opitz, for their breakthrough album "Shabooh Shoobah". Midnight Oil returned to Australia to record "Species Deceases" in 1985 at Paradise. All these albums, and many others were mixed on the Harrison that Graeme Williams and I installed during the studio build.
Sontron soon started to build S-100 based computer controlled equipment using motherboards/racks containing processor, memory, input/output and disk controller cards from US companies like Altair, IMSAI, North Star, Cromemco and Shugart. We settled on Zilog's Z-80 as the microprocessor of choice. Graham's son Gerrard was very much in the mould of his father and quickly took to writing all the software, most of it in Z-80 assembler to get the performance and functionality required. He deserves enormous credit for the subsequent success of Sontron and the Editron products.
Sontron quickly found a market for control of audio and video equipment. As I moved from Uni to an ongoing job at Sontron, I had the opportunity to start designing and building hardware for these projects. We built a number of hardware only control systems, allowing remote control of video and audio recorders, including joystick control. Things began to change during 1979. Graham had supplied equipment to Rodger Savage, who ran Melbourne company Soundfirm, from the Optronics days and had stayed in close contact. When Rodger secured the soundtrack job for the film "Mad Max", he joined heads with Graham and Gerrard to come up with the first iteration of what would later become the Editron products, by building a system to synchronise a U-matic video machine to a multitrack recorder using SMPTE timecode. Graham built the hardware interfaces and Gerrard did all the Z-80 assembler programming.
I didn't have a direct involvement in this first project but I do recall discussing speed control issues with Gerrard. In order to synchronise the video and audio, you need to synchronise the timecode read from the video and audio machines, as they each move from stopped to their full running speed. This is even more tricky with joystick control and fast forward/reverse. You want to be able to drive each machine to synch as fast as possible without overshoot, under changing load depending on the amount of tape on the reels. Gerrard was having problems synching the machines. I had studied control systems at Uni and I discussed with Gerrard how a PID (proportional-integral-differential) control algorithm could solve this problem. Gerrard then implemented this in Z-80 assembler as a core building block of the Editron software.
Some more video/audio sync systems followed, including synchronisation of 16mm and 35mm film projectors to multitrack audio recorders. Film projectors don't have timecode, so Graham came up with an innovative solution. His father, Hilton was an old school mechanical engineer and came out of retirement to hand fabricate encoding disks for the projectors. These consisted of an aluminium disc about 1.5mm thick and 10cm in diameter with a circular row of holes hand drilled just in from the edge. The holes were about 2.5mm in diameter and drilled so that the distance between the edges of adjacent holes was the same as the diameter, meaning around 150 accurately drilled holes. The disc was attached to the main spindle of the projector and two opto-couplers were fixed to brackets on the side, straddling the holes in the disc so that as the disc spins, a square (on/off) wave is produced from the output of each opto-coupler. This allows you to determine the speed of the projector. The two opto-couplers are mounted 90 degrees out of phase. That is, when one opto-coupler detects the edge of a hole, the other is either half way across a hole or half way across the disc material between the holes. This allows you to determine the direction of the film - forward or reverse. Hilton was able to hand drill these disks to amazing accuracy, producing square wave outputs from the optocouplers with negligible wow or flutter. Once the film was loaded and SMPTE time-coded tape was loaded on the tape recorder, the audio could follow the film in perfect synchronism, allowing joystick control from stopped to play speed and up to 3 times overspeed in both directions. Around this time, Editron was coined as the generic name for these systems. I am not sure where it came from but probably Graham or maybe Katherine.
One Friday afternoon in late 1979, Graham came to me and started explaining our next major job. We were to build an Editron system to synch a 35mm film projector to a multi track audio recorder for Allan Eaton Studios at 80 Inkerman Street St Kilda in Melbourne. Allan had won a job to record the soundtrack for a new movie, "The Earthling" that was being shot in Australia, starring Ricky Shroeder and William Holden. The soundtrack was written by Bruce Smeaton and was to be performed by the Melbourne Symphony Orchestra. The recording relied on a then new technique called "Rock and Roll". Part of the reason Allan had won the job was the rock and roll system and he was relying on Graham to provide it - so there was a lot at stake.
Rock and roll involved playing finished scenes from the film in the studio and recording the orchestra live as the film played. This way, Bruce and the orchestra and could use the film action as cues to sync the music. In order for this to work practically, you need to be able to quickly "rock and roll" the film backwards and forwards on each take using a joystick, each time moving the audio recorder in synch with the film. A perfect job for the Editron.
I asked Graham when we needed to have the system ready. He nonchalantly replied "Monday"! That started an amazing week of frenzied activity. We worked late into the early hours of Saturday morning. I pulled together the hardware design while others worked on the mechanicals, using the pre-built parts we had as far as possible. Gerrard got started on putting together the S-100 rack and customising the software. Over the rest of the weekend, we built most of the hardware and mechanicals, again working into the early hours. By Monday morning, we arrived at the studios with a bare skeleton system. We still had to finish the hardware, adapt the projector and get the joystick controller tuned, run cables and install into the studio control room - so we were nowhere near ready. Fortunately, there had been some hold up with the orchestra and they were not ready to record yet. A temporary reprieve.
By Wednesday morning, Bruce and the MSO were ready to start some rehearsals. We had the basic system running but the control feedback was still not tuned so we had to run things with an external signal generator and manually rock and roll the system. This was extremely cumbersome and also prevented Gerard from getting access to the projector for testing. Fortunately, a further holdup with the orchestra combined with general frustration with the manual running gave us the rest of Wednesday to finish things off. The system was working well by Thursday but we still had a lot of tidying up to do in the recording breaks and documentation to finish off. By Friday morning, we had worked over 100 hours without sleep but the job was done and the system worked beautifully.
We built a similar system for Peter Frost Sound Post Production in Melbourne, this time adding a printed circuit motor to drive the projector with an associated motor control amplifier. The original design used a push-pull output stage with multiple parallel J-FET power output transistors. These were relatively new and very expensive. A set of transistors for the power amp cost close to $100 and multiple sets were burnt during the development of the amplifier, without any real progress towards a stable design. When Graham became aware he was more than a little stunned and asked me to take a look at the amplifier. I assessed the J-FET design and came to the conclusion that it was not worth persevering with. I discussed this with Graham, saying that we should look at a completely new design. He suggested another new device called a gate turn-off thyristor. Though fewer devices would be required, they were even more expensive and I was unable to find a wholesale supplier. I decided to redesign the whole thing using cheap, rugged and easily obtainable silicon controlled rectifiers (SCRs) and had a reliable system running in a day or so. Graham was concerned that the rapid turn-on characteristics of the SCR might degrade the printed circuit motor over time. I argued that the self inductance of the motor would effectively suppress the spikes and therefore not affect the motor long term. I couldn't measure any spikes in the lab but I don't think I really convinced Graham. In the end, time constraints and the complete reliability of the design left him with little choice. The system worked without fault for many years thereafter.
Other work at Sontron included some consultancy that Graham was asked to do on the acoustics of the Melbourne Concert Hall. There had been some disquiet about the sound of the hall from the time it was first opened in the early 70s, mainly because the side walls had been built parallel. Graham was called in to acoustically assess the hall and make recommendations to improve the sound. I can only say that I assisted him in measuring the hall acoustics - all the rest was Graham. His recommendations led to a series of suspended inverted clear plastic domes above the performing stage which simulated an acoustic horn radiating from behind the orchestra. There was general agreement after the domes were installed that a worthwhile improvement had been achieved, albeit limited by the inherent design of the building. I have attended many concerts at the hall over the years and always looked up at those domes with appreciation. Some decades later the front end wall surfaces of the hall were rebuilt, rendering the suspended domes redundant.
In Feb 1983 in my last year at Sontron, on Tuesday the 8th to be exact (the week before the devastating Ash Wednesday bushfires), we were at Armstrong Studios in South Melbourne, installing a time code system. Word came through via the radio that a huge dust storm was approaching Melbourne from the north west. During the morning, a strong dry cold front began to cross Victoria, preceded by hot, gusty northerly winds. The loose topsoil in the Mallee and Wimmera areas in far north western Victoria was picked up by the wind and collected into a huge cloud of dust. Meanwhile in Melbourne it was intensely hot. The change was yet to arrive and by 2:35pm it had reached 43.2 °C (109.8 °F), at that stage a record for February. Around the same time, we went up to the roof of Armstrong's and watched as an enormous red-brown cloud a few hundred metres high rolled towards the city like a tidal wave. The dust storm hit us just before 3:00pm, accompanied by a rapid drop in temperature and a fierce wind change that we later learnt had uprooted trees and ripped the roof off houses. Within a few minutes, we could hardly see the ground and the chokingly thick dust forced us back inside. The trip back to Carnegie some time later felt like driving through a Martian atmosphere.
I left Sontron towards the end of 1983, only because they had severe cash flow issues and hadn't been able to pay me anything more than pocket money for months. Of course, I would loved to have stayed. It was the best job I could ever have asked for and the Editron product line was just about to take off but I had bought a house and desperately needed to service the loan. Many years later in the mid 90s, I was contacted by a sound engineer at Crawford Productions in Melbourne who had an old Editron and needed to get it going again to work on some old productions for DVD release. It was not hard to bring it back to life - definitely a labour of love. Once again, Graham was ahead of his time with the Editron and looking back now, I thank my lucky stars that I had the opportunity to work with him.