Audio disc Transfer
During the early years of audio recording, 78 rpm records were a popular medium for families to record and preserve valued memories. Voice letters were popularized as World War II progressed in the 1940s. Servicemen could record messages at a local United Service Organization (USO) club and send them home to loved ones. Some of the most famous classical and jazz musicians of the 1950s and 1960s were recorded on 10 and 12 inch vinyl records. Throughout history, we’ve innovated recording technology to preserve the most important moments. Creative Audio Works can transfer all types of discs, from 16 rpm through 78-rpm records, and monitors every disc in “real time” for optimum tracking and overall quality.
The Audograph Disc
Audograph discs are a unique and challenging “dead” media to work with. Introduced in the mid-1940s, the Audograph was designed as a portable dictation system using thin plastic recording discs. These discs were very flexible and prone to damage. The spiral groove is also very shallow making it hard for the needle to track correctly on playback. In addition, on playback using modern technology, the sound increases dramatically in speed as the disc is played. Because of this, finding the exact pitch and rendering an accurate restoration becomes a challenge.
Exactly how fast the playback should be at any given point in the recording is always questionable. In the past there has been no benchmark. Now with modern technology we can look at hidden frequencies in the recorded audio that are constant, and use them as a benchmark for speed control.
The Audograph is a Constant Linear Velocity (CLV) disc. Simply put, one second of audio requires a set groove travel distance at the beginning of the recording and the same amount of travel at the end of the recording. This design allowed more information to be stored on a small disc.
Rather than a conventional constant-speed spindle drive, mechanical rollers, mounted close to the cutting head, are responsible for driving the surface of the disc as the cutting head travels. For reference, a conventional turntable would record that same set amount of groove travel distance at the beginning, and maybe half that amount at the end of the recording. In the case of the Audograph, the turntable platter speed constantly changes from the beginning to the end of the recording as the circumference increases. As a result, the groove travel distance per second is constant. The unique mechanical aspects of this obscure audio format also adds artifacts like wow and flutter.
Since there seems to be no published specifications regarding the Gray Audograph recorder, we have to make decisions based on the transferred files themselves
The main problem with transferring different formats of that era is that the technology is 50+ years old. Mechanical recording devices of that era have many problems built into them that have to be addressed. The unique mechanical aspects of this obscure format add artifacts like wow and flutter. Inferior cutting head design and inferior speed control all add to the issues and challenges in accurately restoring an Audograph recording.
As standard procedure, all records are cleaned before transfer. Worn records can be digitally enhanced to reduce or remove surface noise such as crackles, clicks, and pops. In some cases, the condition of the disc surface is so badly worn that it would require manual editing. This type of work can be very time consuming.
Once cleaned, we transfer each disc onto a modern turntable using a moving coil cartridge with a custom stylus and a phono preamp. This allows us to view the audio spectrum for each recording and determine how to process each individual audio file.
With the help of tailored software, we correct the playback speed of the transferred digital file. Additional noise and distortion removal services are available to remove or reduce background noise that may be distracting to the listener. Your original Audograph recordings will be returned to you as a CD, digital files, or hard drive.