Vintage instruments/time line
Behavioral research equipment (1950)
In the mid-1950's, Grason-Stadler became one of the first companies in the United States to provide economical, modular, relay-based experiment control equipment for the growing need of behavioral researchers to automate and replicate increasingly complex experiments. Although this relay system continued to fill many research needs, developments in behavioral research and in the life sciences in general have required control and monitoring devices with more speed and flexibility than relays provide. Grason-Stadler's response to these requirements was to develop three separate programming systems; the first was based on relays, the second on solid-state logic, and the third on computer control. All of this took time; in fact it took approximately twenty years for the technology to advance to economical computer control.
Photo: Federation of American Societies for Experimental Biology,
Ruth Sullivan
The Grason-Stadler 162 speech audiometer (1954)
The 162 and E-800 were the two audiometers recognized as the best money could buy. They were in production until 1970 and were built to last. I have overhauled and re-conditioned many that were 15 to 20 years old and still being used. This vintage 162 speech audiometer is from the mid-60's and has a Garrard Lab 80 turntable installed in the plinth. Earlier serial numbers used a different turntable. I can recall a stainless steel tonearm and head, it may have been a Shure Brothers. Later serial numbers were supplied with Acoustic Reasearch (AR) turntables. The output attenuators were custom manufactured by the Ralph Gerbrands Company, Arlington, Mass. A Pickering V15 series cartridge (see Nostalgia) was used on the tonearm head for this vintage.
Note: The 162 speech audiometer was extremely versatile at mixing input signals and routing outputs. It had both input and output attenuators.
The first Grason-Stadler Bekesy sweep frequency audiometer (1956)
The E-800 Bekesy sweep frequency audiometer was introduced in 1956 under license from Georg von Bekesy and installed in clinics and hospitals all over the world. Calibration of this instrument was controlled by a cam that was cut on a milling machine to the frequency response of a matched pair of TDH-39 earphones. There were two curves on the cam, one for Hearing Level (HL) and one for Sound Pressure Level (SPL). Over time as calibration drifted towards the limits of standards, the earphones along with the cam were replaced with a new matched set. The black bakelite cam and the cam follower can be seen directly in back of the green paper table. A Koh-I-Noor Rapidograph refillable graphic pen was used for recording the audiogram. See Nostalgia for a better view.
photo: (1969) E800 Bekesy sweep frequency audiometer, Ben DeRuzzo, Greg Andrews
Note: The E-800 was the first commercially available Bekesy type audiometer.
Series 1200 Solid-State Programming System (1965)
R. L. Grason, S. J. Stadler
The Series 1200 System was Grason-Stadler's response to those researchers who needed sophisticated control of experiment parameters and versatile data acquisition techniques. It was smaller, quieter, and much faster than its relay counterpart. And because it was faster it could make sophisticated control decisions -- from detecting coincidence between discrete nerve cell firings to the generation of random numbers.
Photo: Rufus L. Grason, Steven J. Stadler
Grason-Stadler Co.
West Concord, Mass
Series 1200 provided control of and data collection for a variety of life-science experiments. Its applications ranged from standard schedules of reinforcement in the behavioral sciences through complex multi-alternative forced choice procedures in psychoacoustics, to evoked potential threshold tests in neurophysiology. On the horizon, just a few years away, due to the blockbuster DEC PDP-8 series mini-computer, was the development of the Grason-Stadler SCAT system.
Photo: 1200 series solid-state programming modules
Stephenson B. Porter
Computer Based Behavioral Research System (1968)
The *SCAT system was designed to permit on-line, real-time automation of multiple independent or highly complex single experiments. It was an integrated hardware/software control and data-collection system that utilized a DEC PDP-8 series mini-computer as its central processor. The SCAT hardware extended the basic capabilities of the computer by performing a variety of time-consuming converting, storing, and timing operations. The SCAT software permitted the implementation, through easily-remembered commands, of complex functions such as time-measurement, counting, random number generation, magnitude comparison, and data collection and outputting. The software also supplied a query mode that permitted both interrogation and modification of on-going experiment variables.
*State Change Algorithm Terminology
Photo: Grason-Stadler SCAT system
Steven J. Stadler at the teletype
photo: by peter danielson
The first Grason-Stadler pure tone and speech audiometer (1969)
GS 1701 - A CALCULATED CONQUEST
The 1701 audiometer was Grason-Stadler’s most successful instrument launch to date. And with good reason… nothing else commercially available could match it. It represented a significant step foreward from all others. It was simplicity but with ultimate sophistication in performance, extremely user friendly and reliable. The engineering was amazing and included the most innovative and fully optimized features ever seen. It was the next generation design that fit the formula professionals required at the right moment in time. It became the most popular audiometer of its generation, possibly of all time, and firmly established Grason-Stadler as the industry leader. The 1701 was designed to last through 10 years of heavy clinical use. The instrument shown here was 20 years old when I took this photo and in perfect working condition (GSI 28A in the background). It has been surmised by a few that Rufus Grason named it 1701 after the fictional starship USS Enterprise (NCC-1701) from the TV series Star Trek.
GS model 1720 Otoadmittance meter (1971)
The industries first multi-probe tone, mulit-function middle ear analyzer. Introduced in 1971, the 1720 measured middle ear function in two components. The two components were conductance (G) and susceptance (B) calibrated in millimhos and displayed on the 2 meters simultaneously. The two probe tones were 226 Hz and 678 Hz. Tests at the higher probe tone might reveal pathologies not evident at 226 Hz. At the time, the 1720 was the only electroacoustic instrument available with a higher probe tone than 226 Hz. An optional X-Y plotter permitted the recording of conductance and susceptance curves. The photo shows the model 1720B which replaced the model 1720 in 1974.
GSI 1723 Version 1 (1977)
The 1723 middle-ear analyzer was the replacement for the 1720B. As technology progressed electronic components became smaller which led to the miniaturization of the ear probe that contained the microphone, pressure and stimulus transducers. The 1723 version 1 had a single probe tone (226Hz) and measured compliance in millileters (ml). Several months later the 1723 version 2 was introduced. It included all the features of the V1 plus a 668Hz probe tone and conductance/susceptance measurements. Both instruments had an on-board X-Y plotter for graphical recording of tympanograms and acoustic reflexes. The model 1723 would become the star of the GSI product line.
