McIntosh History according to Roger Russell

In 1962 McIntosh Laboratory Inc. started what was to become one of the most successful and longest running marketing campaigns in the Consumer Electronics industry, The McIntosh Amplifier Clinic.

McIntosh amplifiers were and are "Still the Best" but they had to find a way to prove it to the Consumer. They did this by testing amplifiers in stores; with Customers as witness they were able to show that McIntosh was the best.

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nsgarch said:

George, you're not serious?? You just discovered RR's website??

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nsgarch said:

a clean bill of health, just like they give to working girls!!

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Art Janszen had been a consultant for McIntosh for several years. He visited our acoustics lab about this time to test his new idea for spiral wrapping the electrodes for his electrostatic tweeter. Earlier versions were constructed using short parallel wires connected together.

Gordon Gow was interested in the Janszen tweeter as a possible high frequency speaker in a McIntosh system. He was also concerned about peak power levels needed to reproduce musical instruments at high frequencies. We set up a microphone at 1 meter and used tone bursts to see how the tweeter will handle short bursts of high frequency power. As the power level re: 8 ohms increased, the acoustic output increased by an equal amount, but at higher power the output began to decrease. We found that by blowing across the tweeter, the output would be temporarily restored. The reduced output was caused by ionized air. The electric stress in the air had exceeded 100V per mil. Ions were produced that in turn discharged the polarizing voltage and caused the output to decrease. By blowing away the ionized air, the polarizing voltage was restored until new ions were formed.

We then compared our dome mid-range at the same sound pressure level and were able to increase the driving power level by many dB above the Janszen while still remaining completely linear.

Gordon learned that the Dayton-Wright electrostatic speaker was enclosed in sulfur hexaflouride gas to eliminate this problem. The thin membrane that enclosed the gas was porous, however, and exhibited the osmotic process where the higher density gas molecules migrated through the membrane to the lower density air. The speakers needed to be periodically recharged with gas.

As a result of this research and other factors, Gordon decided not to pursue the electrostatic speaker as a viable product.

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