Editorials

Knobs, Buttons and Dials

The phonograph, also called gramophone or record player, is a device introduced in 1877 for the recording and reproduction of sound recordings. The recordings played on such a device consist of waveforms that are engraved onto a rotating cylinder or disc. As the recorded surface rotates, a playback stylus traces the waveforms and vibrates to reproduce the recorded sound waves.

Enter Edison

The phonograph was invented in 1877 by Thomas Edison. While other inventors had produced devices that could record sounds, Edison’s phonograph was the first to be able to reproduce the recorded sound. His phonograph originally recorded sound onto a tinfoil sheet phonograph cylinder, and could both record and reproduce sounds. Alexander Graham Bell’s Volta Laboratory made several improvements in the 1880s, including the use of wax-coated cardboard cylinders, and a cutting stylus that moved from side to side in a “zig zag” pattern across the record.

In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center. Other improvements were made throughout the years, including modifications to the turntable and its drive system, the stylus or needle, and the sound and equalization systems.

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A Brief Guide on Coffee Roasting

Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell, and density. Unroasted beans contain similar acids, protein, and caffeine as those that have been roasted, but lack the taste. Heat must be applied for the Maillard and other chemical reactions to occur.

As green coffee is more stable than roasted, the roasting process tends to take place close to where it will be consumed. This reduces the time that roasted coffee spends in distribution, giving the consumer a longer shelf life. The vast majority of coffee is roasted commercially on a large scale, but some coffee drinkers roast coffee at home in order to have more control over the freshness and flavor profile of the beans.

The Process

The coffee roasting process follows coffee processing and precedes coffee brewing. It consists essentially of sorting, roasting, cooling, and packaging but can also include grinding in larger scale roasting houses. In larger operations, bags of green coffee beans are hand or machine-opened, dumped into a hopper, and screened to remove debris.

Some coffee drinkers roast coffee at home in order to have more control over the freshness and flavor profile of the beans.

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An Ode to Stereophonic Sound

Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of directionality and audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term “stereophonic” applies to so-called “quadraphonic” and “surround-sound” systems as well as the more common two-channel, two-speaker systems. It is often contrasted with monophonic, or “mono” sound, where audio is in the form of one channel, often centered in the sound field. Stereo sound is now common in entertainment systems such as broadcast radio and TV, recorded music and the cinema.

How It Works

Stereo sound systems can be divided into two forms: The first is “true” or “natural” stereo in which a live sound is captured, with any natural reverberation or ambience present, by an array of microphones. The signal is then reproduced over multiple loudspeakers to recreate, as closely as possible, the live sound.

Secondly “artificial” or “pan-pot” stereo, in which a single-channel (mono) sound is reproduced over multiple loudspeakers. By varying the relative amplitude of the signal sent to each speaker an artificial direction can be suggested. The control which is used to vary this relative amplitude of the signal is known as a “pan-pot”. By combining multiple “pan-potted” mono signals together, a complete, yet entirely artificial, sound field can be created.

Stereophonic sound attempts to create an illusion of location for various sound sources within the original recording.

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