How do you make a phonograph?

The production of a modern disc phonograph record is quite different from a cylindrical phonograph. I'll try to give a basic outline of the electro-mechanical process as it was before digital recording was introduced.

First, the musicians perform into microphones. Signals from the microphones are boosted using either high quality microphone amplifiers or step-up transformers, and then fed to a professional multi-track analogue tape recorder. I believe that most studios used 32 track Ampex decks. To preserve fidelity the tape speed on these tape recorder were very high. I believe that typically it was 32 inches per second. This high speed reduces noise and distortion, and increases frequency response and dynamic range of the recording.

Once recorded, the multiple channels are mixed down to two channels for stereo, and these two tracks are laid down on a master stereo tape.

The next step is to produce a master disc using a special cutting lathe. The cutting lathe operates something like a record player only in reverse. It has a rotating platter like a turntable where a blank master disk is placed and turned. Held above the rotating disk is a record cutting head with a special stylus that's used to cut a groove into the blank master disk.

The master stereo tape is played, and the stereo signal from the tape player is fed to very powerful and accurate amplifiers. The high power signals from the amplifiers drive the stylus on the lathe's cutting head, causing it to vibrate in sympathy to the input stereo signal. The cutting head is lowered onto the outside of the rotating master disk, much like a phono cartridge on a regular record player. When the vibrating stylus contacts the surface of the master disk, it cuts a groove into the surface. While this happens, the entire cutting head moves tangentially across the rotating blank master from the outside of the disk to the inside much like a tonearm on a record player.

Once the side is cut that side of the master disk is created. The process is repeated for the second side of the record using a new blank master.

This master is used to create molds which are used to press the disks which are sold to people. The molds, or stampers, are like negatives of the master disks and the final vinyl product sold to people. Instead of grooves the stampers have raised ridges. The stampers press vinyl blanks. The raised ridges being pressed on the blanks create the grooves. Now you have the final product ready for playback on a record player.

This is a description which I believe is basically correct, and if I've made any errors please let others know.

Answer

From the following web site: http://www.creative-science.org.uk/RS2phono.html

The phonograph is made up of several parts. Firstly the horn is used to collect the sound. This can be made of cardboard, in the Rough Science version we used a large metal funnel. At the bottom of the horn we need to fix a diaphragm. The diaphragm needs to be made of a thin but stiff material that will be strong enough to hold the stylus but be able to vibrate to the sound. We found that we got very little vibration by fixing the diaphragm directly onto the horn. However, when we used a small tin can fixed to the horn it worked very well (the tin can acts as a 'sound box' and increases the efficiency of transfer of sound to vibration). The thin metal bottom of the can formed the diaphragm. In the middle of the diaphragm we pushed a drawing pin through to form the stylus. As a simple test when you talk into the horn you can easily feel the drawing pin vibrate.

The recording cylinder we used was formed of two wooden circles mounted on a piece of studding (long thread). These were held apart and fixed in place by wooden blocks between them and the whole thing was then covered in many layers of wax till we had built up a wax cylinder. Two nuts were placed on the thread and these were held in place on two supports fixed to the wooden base of the phonograph. A handle was then placed at one end of the thread. When the handle was turned the cylinder rotated but because of the screw thread it also moved along. The wax cylinder now needs to be made as precise a shape as possible. This is done by holding a razor blade firmly onto one the side of the wax disc while turning it fast. When the handle is turned very fast the razor shaves off excess wax. You don't need to move the razor as the cylinder will move along on its own accord. If this is done a few times a wonderfully smooth and precision cylinder of wax can be produced.

The horn-diaphragm-stylus unit then needs to be fixed onto the base but able to move so that the position of the drawing pin on the wax can be adjusted. This is best done using a hinge of some construction and another screw thread to make the final adjustment onto the wax.

First answer by ID2429797231. Last edit by Little mugwump. Contributor trust: 72 [recommend contributor]. Question popularity: 137 [recommend question]