A really intersting article from 1955 about Japan’s audio show…read the heading “Good audio isn’t exclusive to the United States”
In 1929 Wente and Thuras designed the Western Electric 555 speaker driver capable of 100-5000 hz freq. range with an efficiency of 25% (compared to 1% of todays drivers). This was “compulsary” as only very low powers (<10watts) were available. They had to fill huge 2000 seat cinemas with sound with very little power….necessity is the mother of invention.
The 555 is a great driver…I mean really great, see the frequency sweep below strong from 70hz upwards to 6000hz with no loading. I have had Goto, the 570dx, and it gets nowhere near that. With Gotos you always fear someting is going to break. 555 have been runing for many decades….suffered abuse of the working enviroment…they are still around with original diaphragms!
Using 555’s is one hell of a comitement to sound. You need big and long horns (15a/b, 16a/b….), power supplies; not for the casual hifier at all.
The big Studio machines can be divided into three classes: 1/4 inch (6,35 mm), beginning with the 50ies of the last century 1 inch (25,4 mm) and from 1970 preferable 2 inch (50,8mm) wide tapes. There are also Semi-Professional and Small-Studio machines which came with three motors and three heads, too.
The Studer C37 (1961) demonstrates the progress which Studer has reached within one decade. Using the service-friendly module technology it was possible changing a C37 easily from a Stereo into a Mono version by just exchanging the modules and the head frame. The writer Rinaldo Bassi reported 1966 in the French “La Nouvelle Revue du Son” about a modified C37 reaching a contact noise pitch of 100dB! The 4 channel sister machine J37 was used as the work horse at Abbey Road Studios, also recording some of the Beatles sessions. The C37 produces a wonderful warm tube sound.
Replacing step by step the successful A80 family the elegant looking A820 (1984) has been developed in the “euphoris digitalis period”. The A820 multi-channel version became the tape deck bases for the Digital Studer Machines. By means of five motors the A820 provided a new operating flexibility every Studio Professional had dreamt of. The technical properties are numerous and need to be listed and described on 12 pages in the A820 brochure. It is not only fun working with this exceptional machine, one will also experience a new haptic feeling by recording with this outstanding Master Tape Recorder.