Sound From Substance; Acoustic Design Reconsidered
By R.J. Wakeman
There it stands–in a corner of the dining room–the old family Victrola. It was inherited from Aunt Maude who kept the Victrola polished and pristine for decades. But now its design and mahogany wood clash with the Danish modern furniture in the living room. The Victrola is almost forgotten; it is never played. The need to change needles when playing records is forgotten, unknown.
Today it is common to consider an old phonograph as an antique which is rarely played and usually serves as a display piece and a family artifact from the past. However, those of us who are daily listeners to the early disc and cylinder phonographs and records still consider phonographs as functioning and working machines which need to be kept clean and given occasional lubrication. Early phonographs and records have a special “sound” of their own and we seem capable of ignoring or “tuning out” record surface noises. The happy sounds of a snappy fox trot can still help to brighten the day and there is real aesthetic value when playing a beautiful concert or opera record on a magnificent cabinet Victrola. Similar to a photograph, a phonograph record represents a captured
moment in time. During the 1910’s and early 1920’s it was a way of life for the young folks in the family to roll back the parlor rug on Saturday evening and keep the Victrola spinning records as they danced to the latest popular tunes. Then Sunday, after an early dinner, the family would gather in the parlor to spend a quiet afternoon listening to ballads, quartets, and semi-classical records; there would always be several of John McCormack’s Red Seal ballads.
In the United States the term “phonograph” has come to mean almost any machine designed to play records—disc or cylinder. However, for most of the world the term “gramophone” is used for machines that play disc records while “phonograph” indicates a machine that plays the Edison disc or cylinder records. New collectors can be confused between “reproducer” and “sound box.” Since Edison used the term “reproducer” and Victor “sound box,” there is a tendency to use “reproducer” when referring to cylinder phonographs and “sound box” when referring to disc phonographs. However, many disc companies in the early years used the term “reproducer,” including the Columbia Graphophone Company and the Brunswick-Balke-Collender Company. Most collectors seem to be comfortable using both terms.
The Victor Concert Sound Box
The “heart” of any mechanical phonograph is the reproducer and at the center of the reproducer is the diaphragm, which converts the mechanical vibrations from the stylus bar into actual sound. The diaphragm is meant to “float” and vibrate between two rings of soft gaskets. The diaphragm should be as compliant as possible in order to vibrate and quickly return to original position. The diaphragm vibrates with every sound in the room; reproducers should be restored to permit the diaphragm to vibrate as freely as possible. When not in use, position the reproducer so that the weight does not rest on the needle, stylus, or stylus bar; this permits the diaphragm to freely vibrate with sounds in the room. Compliance is the key to the best sound reproduction—and to the least record wear.
As a needle or stylus travels through the record grooves, it becomes deflected at each undulation. These movements are magnified in amplitude by the stylus bar, which is a simple lever, and the vibrations are impressed upon the center of the diaphragm. The diaphragm, being a compliant material, ensures the return movement of the needle or stylus. The vibrations of the diaphragm are passed onto the air column within the tone arm, where they pass into the horn. Sound reproduction depends on the area and stiffness of the diaphragm; low sound waves depend on the air loading capacity of the diaphragm while high notes depend on the inertia (resistance to change in motion or rest) of the diaphragm. Insufficient compliance occurs when the diaphragm is too thick or the support gaskets are too tight. The essentials are a diaphragm of elastic material supported at its periphery by rings of soft rubber to insulate it from the rigid reproducer shell. The edges of the diaphragm should not contact the shell. The gaskets should be of the exact size and fit to provide a complete air-tight seal for the edges of the diaphragm. Every adjustment on the reproducer can make an enormous difference. Reproducers are “tuned” by stylus bar tension and by pressure on the gaskets. Stylus bars should be adjusted to be semi-rigidly held in place. Often the desired degree of tightness is found by trial and error.
The Victor Exhibition Sound Box
Any diaphragm, whether made of glass, mica, metal, or some other material, has a resonant point or points which result from its size, thickness, compliance, and strength of clamping. These irritating resonant peaks seem to be common to mica diaphragms. When a sound wave that is approximately of the same resonance point as a diaphragm is thrown mechanically on that diaphragm, there is an irritating blast of sound(s) coming from the reproducer. The ideal diaphragm should have resonant points above that of vocal or instrumental vibrations and possess the necessary resilience to transform sounds without distortion and at the same time carry the loudest sounds without over-vibration.
Diaphragm gaskets usually consist of lengths of soft rubber tubing on each side of the diaphragm and held in slight compression. Edison reproducers used thin flat rubber washers and the later Victor No. 2 and No. 4 sound boxes have solid rubber gaskets. With time, the old original gaskets can become hard and lose compliance. It is not unusual to find gaskets that are dried, cracked, and even breaking to pieces. Solid rubber gaskets appear to be less prone to hardening with age than the tubular variety. Reproducers can be damaged by careless handling, as when securing a needle into the chuck so tight that the diaphragm can be cracked or pulled out of shape when trying to release the needle. Inadvertent knocks or blows to the stylus or diaphragm can cause damage.
“Counterweight For The EMG” by William McKnight Toner, Hillandale News, No.194, October 1993, Page 224
Some collectors have devised a counter-balance to reduce the weight of the reproducer and tone arm on the record, thus helping the diaphragm to have more compliance and cause less record wear. These devices vary in design and size; they can make changing needles less convenient.
The material from which a horn is made makes relatively little difference to the sound as it is the column of air in the horn which is vibrating. In the case of paneled horns, the joints should be tight; the panels should not vibrate. The throat of the horn should have an airtight connection with the reproducer.
Throughout the 1910’s and until late 1925 most U.S. disc phonograph companies produced reproducers with mica diaphragms. Unless otherwise stated, it could be assumed that mica diaphragms were used. Modern macromolecule plastics had not yet been developed, thus there was need for a firm semi-flexible diaphragm material. Soft rubber tubing was the standard gasket material for most mica diaphragms. An article on page 118 of the January 15, 1920, issue of the Talking Machine World stated that imported mica carried a 25% duty. American producers complained to the U.S. government and requested that the tariff be reduced as imported mica was essential to the industry. During World War I good quality mica became difficult to obtain due to war industry demands.
Mica is a mineral which is noted for its easy cleavage and for marked elasticity, flexibility, and toughness of even thin sheets.
Chemically, mica is a complex silicate of aluminum. Some varieties of mica contain iron, magnesium, lithium, or rarely other minerals. There are seven important forms of mica minerals, of which Muscovite [potassium mica – H2KAl3(SiO4)3] is the most common and most useful. Mica minerals are found in pegmatites with intruding mica sheets. They may occur as small flakes, parallel veins, in small pipes, or as massive layers. Mica ranges in color from colorless transparent to jet black. India is the main source of mica, where “books” as much as fifteen feet across are not uncommon; more than half of the world’s supply of mica comes from India. In 1919 India alone exported 2,800 tons of mica valued at $2,915,034. In India the mica is widely distributed, with the main center at Koderma, in the Hazaribagh district. Prospecting for mica is by trial and error; no scientific method for determining the presence of good quality mica has been developed. Commercial quality mica is also found in Brazil, lower Canada, Alabama, Colorado, and South Dakota. An article on page 47 of the December 15, 1922 issue of the Talking Machine World stated that Guatemala was becoming a good source of mica and was producing 600 to 1000 pounds per month, all of which was shipped to the United States.
Mica books are split along the cleavage into sheets of the desired thickness and trimmed into rectangles by shears with the stained or damaged parts being rejected or saved for other purposes. The sheets are sorted according to size, transparency, color, and freedom from spots or stains. Flaked or powdered mica was used in the early years to give the glistening effect of snow scenes in Christmas window displays.
It is difficult to buy a sheet of mica and cut your own diaphragms because the scissors or even a razor can cause the mica to crack in all directions while the edges crumble into flakes. Cutting is best done under water with special machines, such as a band or scroll saw with fine tooth blades. Still, some collectors have had success using an Exacto knife or with a pair of fine scissors, although cutting can quickly dull scissors. To cut mica to size, some place the mica between gold beater’s skin (used to produce gold leaf), which is the outer membrane of a calf intestine and is very strong and stretchy. Cutting mica with a saw can generate a silica dust that is toxic and known to cause silicosis. Mica will bend only a small amount before cracking. In the early years of the phonograph it was possible to purchase mica diaphragms from most phonograph dealers, but today the few that are produced are mostly available from the antique phonograph dealer/repairmen. In appearance mica diaphragms resemble thin discs of clear glass, sometimes tinted a very light yellowish brown. They average approximately 1/6 millimeter in thickness and most are fully transparent. Similar to glass, a mica diaphragm can give a clear ring if dropped or flicked with the finger; from the pitch of the ring, one can tell if it is thicker or thinner than average, for in any batch of a given size, there is some variation in thickness. It is difficult and somewhat hit-or-miss, but it is possible to take a mica diaphragm that is thicker than usual and split it into two diaphragms, one or both of which may be thin enough to offer greater compliance than the original thick one. If the razor cleaves at an angle, however, the mica can part unevenly. One repairman tried this and reported the thinner diaphragm had excellent sound reproduction with less tendency to have resonant peaks, however record surface noise was increased.
Mica diaphragms should be free of cracks and de-laminations, which can cause rattles or blasting. The tonal qualities of different micas can vary greatly. The connection of the stylus bar at the center of the diaphragm should be firm; some are cemented in place while many are held in place with a tiny screw. In removing the screw (with a jeweler’s screwdriver) great care should be taken not to drop the nut or screw, for they are tiny and can suddenly just disappear. In replacing the screw and washer, turn until it is just tight enough to grip the diaphragm lightly. It is essential not to damage the mica by over tightening the screw. A small drop of beeswax should be melted onto it on both sides. It is not unusual to find an old mica diaphragm beginning to split at the center where the stylus bar attaches.
Companies that advertised mica in issues of the Talking Machine World: (many firms advertised “ruby” mica; evidently it was the preferred form of mica for use in forming diaphragms.)
Acme Mica Co, Inc., 56 Bleecker Street, New York City, New York
Allen Mica Company, 20 West 20th Street, New York City, New York
American Mica Works, 47 West Street, New York City, New York
Central Music Sales Company, 711 Wells Street, Milwaukee, Wisconsin
Everybody’s Talking Machine Company, 38 North 8th Street, Philadelphia, Pennsylvania
Favorite Manufacturing Company, 105 East 12 Street, New York City, New York
Hirsch Mica Company, Flushing and Porter Avenues and Thames Street, Brooklyn, New York
International Mica Company, 37th & Brandywine Streets, West Philadelphia, Pennsylvania
Phonograph Appliance Company, 109-113 West Broadway, New York City, New York
Stenzel Mica Corporation, New Dorp Station, Staten Island, New York
Watson Brothers, Inc., 170 Purchase Street, Boston, Massachusetts
William Brand, 27 East 22nd Street, New York City, New York
The Victrola No.2 Sound Box
In 1918 when the Victor Talking Machine Company introduced the Victrola No. 2 sound box with the larger mica diaphragm, the stylus ratio was increased to 1.66, from the 1.44 ratio of the older and smaller Exhibition sound box. This change accentuated the “ringing” tones of Enrico Caruso and other Victor opera and concert artists; the change favored the higher sound registers. Victor was reported to purchase approximately thirty tons of mica a year, although much was rejected as unsuitable to form diaphragms.
A new use for mica occurred when electronic vacuum tubes were developed in the 1910’s. Small sheets of mica were used to form bridges or spacers to hold the tube elements in position and insulated from each other at uniform distances. Mica was also used in electronic resistors, condensers, transformers, and rheostats. Mica is not subject to changes in humidity and has unusual chemical and thermal properties; it can withstand high temperatures and high voltages without puncturing. Mica is used in equipment that requires high temperatures, including rockets, missiles, satellites, and jet engine ignition systems. It is often formed into washers, discs, tubes, and plates. Because of mica’s heat resistance, transparent sheets of mica called, “isinglass” were used for viewing windows in furnaces. In Czarist Russia isinglass sheets were used in many homes instead of window glass. Mica, however, lacks the uniformity of manufactured substances and can lose pliance over time.
From the October 15, 1922, Talking Machine World, page 83: Mica diaphragms were offered for sale by the Central Music Sales Company, 711 Wells Street, Milwaukee, Wisconsin. Special quotations were available for quality lots; 5% discount for cash with order.
Size (inches) Brand Price per Diaphragm
1 23/32 Victor Exhibition, etc. …………………………….18 cents
1 7/8 Victrola No. 2, Silvertone, etc………………………24 cents
1 15/16 Heineman, Thomas, etc..……………………………..39 cents
1 31/32 Vitanola, Mandel, etc…………………………………..26 cents
2 1/16 Heineman, Empire, etc………………………………..39 cents
2 1/8 Sterling, Starr, etc…………………………………………41 cents
2 5/32 Columbia, etc……………………………………………….43 cents
2 3/16 Orotone, Mobley, etc……………………………………46 cents
2 ¼ Weser, Cirola, etc………………………………………….50 cents
2 3/8 Pathé, etc………………………………………………………54 cents
2 7/16 Jewel, Blood, etc……………………………………………56 cents
2 9/16 Brunswick, Orotone, etc………………………………..72 cents
From the February 15, 1923, Talking Machine World, page 43: Mica diaphragms were offered for sale by the Favorite Manufacturing Company, 105 East 12th Street, New York City.
Size (inches) Brand Price per Diaphragm
1 23/32 Victor Exhibition, 1st grade……………………….15 cents
1 7/8 Victrola No. 2, very best……………………………18 cents
1 31/32 Sonora………………………………………………………20 cents
2 1/16 Meisselbach……………………………………………..22 cents
2 3/8 Pathé, new style……………………………………….45 cents
2 3/16 Columbia No. 6…………………………………………25 cents
2 9/16 Pathé or Brunswick…………………………………..45 cents
Thomas Edison’s 1877 tin foil phonograph featured a recording diaphragm of thin steel and a reproducing diaphragm of mica. For wax cylinder records Edison developed recorder diaphragms made of celluloid, varnished silk, and then thin glass. Edison reproducer diaphragms were made of thin French glass which was delicate; large vibrations could cause the glass to break. Edison found mica diaphragms to flex with greater ease without breaking, and this permitted louder reproduction. Edison experimented with layered mica diaphragms, with each layer a smaller disc; the layered mica faced toward the horn opening. In 1906 a court injunction prevented Edison from continuing the manufacture of the layered mica diaphragms in the Model “C” reproducers. The mica diaphragms were also prone to resonant peaks. Edison attempted to correct the resonance problem with stamped thin copper diaphragms. Copper diaphragms proved more durable and simpler to fabricate than mica. They also gave increased volume.
Over the years there were changes in the shape and design of the rings and ridges impressed on the copper diaphragms; the concentric rings tended to produce a smoother tone and give more compliance, especially for the lower sound frequencies. The rings also tended to decouple portions of the diaphragm at the problem frequencies for resonant peaks, extended the sound range, and enabled the diaphragm to respond to greater physical movement. As new Edison reproducers were designed they were equipped with larger diaphragms to enhance the lower frequencies. Edison also used harder surface records and reproducers with heavier floating weights; more energy could be transferred from the record to the diaphragm. Edison’s use of the floating weight kept his reproducer diaphragms more or less covered and hidden from view. Thus they were protected from casual damage that may occur when handling.
Hinges on Edison reproducers should be clean and smooth with no rattle. When restoring a copper diaphragm reproducer it is important to carefully scrape away the old gasket. Some collectors form new soft rubber gaskets from old bicycle inner tubes. Often the Edison copper diaphragms are found corroded or oxidized. The diaphragm should be polished with Brasso to remove the oxidized layer, taking care to avoid pressures that could flatten the ribs. The flutter and wobble sounds common to many of the early Edison cylinder phonographs are not the fault of the diaphragm but are due to a slipping belt, unevenly worn gears, and/or worn bushings, especially at the ends of the governor shaft. After June 1915, the copper recorder and reproducer diaphragms for the Edison business machines were nickel plated.
In 1892 when Lieutenant Gianni Bettini designed his “Micro-Phonograph” larger diaphragm reproducer with the spider stylus attachment, he used mica or aluminum diaphragms instead of the French glass used in the Edison “speakers.” Bettini also made multiple diaphragm units. In 1901 when Edwin H. Mobley introduced the Mobley reproducer attachment for the Edison Automatic reproducer, he added an extension to the floating weight and used a stamped aluminum diaphragm. The added weight improved tracking and gave more volume. Edison sued for infringement of three of his patents and the Mobley attachment was soon gone. However, Edison did add more weight to his later designed reproducers.
1909 was a year of changes for Edison and his associates. Damping of the glass diaphragms used in recorders had been by the use of rubber rings. Now it was discovered that viscous dampened gaskets gave a marked improvement in recording sounds, especially for the elusive sibilants—the “f”, “s”, “t”, and “z” sounds. The edges of the glass diaphragms were held “floating” in semi-fluid gaskets; this also increased the volume incised into the records.
For their cylinder Graphophones, the American Graphophone Company produced reproducer diaphragms that more or less followed the design, shape, and size of those produced by the Edison Company. Columbia reproducers have been found with diaphragms of plain mica, stepped mica layers, and pleated copper. The Columbia “floating” reproducers used to play wax cylinder records were simple in design and did not require a stylus bar or linkage; the stylus was cemented onto the center of the diaphragm. Later Columbia reproducers did have stylus bars with linkage similar to the type used by Edison. In 1905 Columbia introduced the 20th Century Graphophone which featured a 4-inch diameter reproducer (with a 3-inch diaphragm) called the Higham loud-play reproducer. The diaphragm linkage was connected to a semi-circular vulcanite “shoe” which partly surrounded a rotating amber wheel. Continuous tension on the diaphragm produced sound waves greater than any reproducer method used at the time. In 1908 Columbia introduced the #15 “extra-tension” reproducer to play the new Columbia Indestructible celluloid cylinder records. The new reproducer had both a floating weight as well as a small leaf-spring to put additional pressure on the cylinder and thus increase the volume.
The Columbia No.7 Floating Reproducer. This simple design with stylus cone cemented to the center of the diaphragm was also used by several European brands.
The Columbia No.12 (Lyric T-3) Reproducer.
The Columbia Analyzing Sound Box with the spring clamp needle holder. Earlier Columbia sound boxes had the more conventional thumb screw.
The Columbia No.12 Reproducer as supplied in 1924.
In the early years of the disc gramophone, Emile Berliner, Fred and Will Gaisberg, and Calvin Childs were still using glass diaphragms for recording. The acoustical recorders for lateral-cut disc records are almost never seen while the recorders for cylinder machines are more familiar. The recording equipment used by the various record companies was usually kept secret. The recording engineer had at his disposal several recorders with diaphragms of different thicknesses, each designed to suit the qualities of different vocalists or instruments. A soprano or tenor voice required a diaphragm of more flexibility than a contralto or baritone. It was the same for high pitch instruments, such as the flute. Instruments of lower registers, as the saxophone, required a heavier diaphragm. Thus the diaphragm could be suited to the artist. Larger diaphragms enabled much-improved recording. In 1905 Hawthorne & Sheble introduced an unusual aftermarket reproducer; it could be adapted to fit almost any brand of talking machine. It had a stamped aluminum diaphragm which was often painted with colorful lacquers.
Edison Rice Paper Diaphragms
The Standard Edison Diamond Disc Reproducer. Note the heavy floating weight. This reproducer has been restored with an experimental Styrofoam diaphragm; a dental floss loop is used as the stylus linkage. Sound reproduction outperforms the original aged Edison rice paper/shellac diaphragm.
In late 1912 when Edison introduced the Diamond Disc reproducers, the basic design was not significantly different from reproducers used on the earlier Edison cylinder phonographs. The diaphragm, however, was most unique; it consisted of layers of rice paper impregnated with shellac. The rice paper was from the fibers of a shrub called the rice plant (Tetrapanax papyriferus); the paper is smooth, strong, and nearly air-tight. The rice paper sheets were bonded together with thin layers of shellac and the exterior of the diaphragm was also coated with shellac. The resulting diaphragm was air-tight, soft, and pliant. A circle of graduated cork was cemented to the center of the underside of the diaphragm, covering approximately three fourths of its surface, and a small ivory, ceramic, or celluloid apex button was glued to the top-center of the diaphragm. A small hole was drilled through the center of the cork and rice paper; a stylus linkage of braided silk was threaded from the stylus bar through this hole and glued to the apex. The apex/cork functioned as a piston which had freedom of movement due to the limber edge of the diaphragm. The braided cord stylus linkage acted as a filter and provided a balance of sound over the mid-audio frequencies. When the reproducer is off the record, the diaphragm remains flat. When the reproducer is lowered onto the record the diaphragm sags slightly downward, under the pressure of the floating weight. As the rounded-tip of the diamond stylus travels through the record grooves, the diaphragm is either pulled down below its original “sagged-down” plane, or it snaps above this plane, depending on the modulation of the vertical grooves. The edges of the diaphragm were suspended with gaskets of thin rubber or cork faced with paper. With the use of the harder celluloid Blue Amberol cylinder records and the Edison Diamond Disc records with surfaces made of Condensite, Edison was able to use precision-ground diamond styli and much heavier floating weights and thus could recover more volume from his reproducers.
Does shellac harden over time? If the Edison diaphragms are a valid indicator, it does. Listening to the Edison Diamond Disc records today, it is evident that there is more “sound” recorded into the records than is being recovered by the original Edison reproducers, even when new soft rubber gaskets have been installed. How to make the old shellac diaphragms more compliant? Some collectors attempt to use Vaseline or oil treatments. The late reproducer repairman, Bob Waltrip of Levelland, Texas, developed the method to cut off the cork and ceramic cone from a diaphragm and slowly dissolve the original shellac by immersing the diaphragm in organic solvents. Even a broken piece of a shellac record dropped into alcohol will gradually dissolve. After a week he could use a sharp Exacto blade to separate the rice paper layers; each layer was cleaned in acetone and dried. The rice papers were carefully reassembled and saturated with freshly-dissolved flake shellac, forming a new and more compliant diaphragm in the original Edison manner. With a compass Mr. Waltrip would draw a new cork disc and with a Dremel Moto tool, taper the disc from center to the outer edge before cementing onto the diaphragm. More of the original “sounds” can be recovered from the Edison discs by this arduous method. It can also repair/restore a diaphragm that has a hole—possibly caused by a screwdriver that slipped. After years of working with the Edison reproducers, Mr. Waltrip found that the standard Edison Diamond Disc reproducer diaphragms had seven to nine layers of rice paper, the Edisonic had eleven layers, and most Amberola diaphragms were found with four layers. In recent times some collectors have experimented with forming Edison diaphragms from modern plastic materials, including Styrofoam.
The Condensite Edison used for the surfaces of his thick Edison Diamond Disc records is similar to Bakelite. Bakelite and Condensite were among the first true thermoplastics; the Belgian chemist, Leo Baekeland, introduced Bakelite in 1909 (Rayon was introduced in 1911). Bakelite is formed by the reaction of phenol (a highly toxic compound) and formaldehyde under heat and pressure and with an alkaline catalyst. The resulting resin is insoluble and is resistant to heat. It can be molded or machined into various shapes and can be colored as desired. It is a much harder compound than shellac. Bakelite products usually contain wood flour fillers. Bakelite is often used as a non-conductor for electrical devices, distributor caps, wire insulation, etc.
Even in the early 1920’s when other inventors were beginning to have some success with electrical recording, Thomas Edison still believed that acoustic recording was the best method and could still be improved. Edison experimented with recording diaphragms made of Condensite coated rice paper fastened to the gaskets with rubber cement so that the diaphragm was not rigidly held. He also experimented with celluloid diaphragms of different thickness.
During World War II the development of man-made macromolecule plastics proliferated. The use of nylon, acrylic, neoprene, polyethylene, vinyl, and many other polymers took the place of natural materials that were no longer readily available. Modern plastics are polymers and composed of long chains of hydrocarbons. Polymers can be heated and formed into shapes; they are usually resistant to chemicals and can be thermal and electrical insulators. In our modern world we are surrounded by items made of plastic; it is hard to imagine living without them. Generally polymers are light weight and have varying degrees of strength. They can even be processed to form thin fibers or intricate parts.
Celluloid was one of the first plastics. Cellulose is a sugar molecule formed into long chains; it gives strength and support for higher plants. Wood consists of fifty to sixty percent cellulose. Cellulose can be changed into nitrocellulose by reacting a pure, finely divided form of cellulose, such as wood flour, cotton, or paper, with nitric acid. Celluloid is made by dissolving nitrocellulose in an alcoholic solution of camphor, producing a hard material. It was developed by W. H. Hyatt, a chemist, in the 1860’s. Celluloid can be colored and molded or extruded into a variety of shapes. Its chief disadvantage is it flammability. Camphor is a distillation product of the Oriental camphor tree (Cinnamomum camphora); it has a strong, resinous odor and is a major component of many old patent medicines, such as Camphophenique.
Shellac is derived from the protective layer of lac produced by Kerria lacca, a scale insect that lives on tress in the East Indies, Malaya, and India. The life cycle takes about six months. Thousands of these scale insects side-by-side can secrete enough resinous lac to completely cover stems. The largest yields of lac are obtained by harvesting infested stems, usually in June and November. A crisis in the supply of shellac occurred in the fall of 1919 when the harvest of lac in India was only one quarter of normal. In shellac records the shellac component represented approximately five-eighths of the material used for better quality records. The exact formula used for making shellac records varied from company to company and from decade to decade. It was usually a company secret. Early varnish, now often termed heirloom varnish, was made by boiling shellac with linseed oil. The resulting varnish is oil, alcohol, and water proof, while shellac alone is not.
By the late 1910’s the basic phonograph and record patents held by Victor, Columbia, and Edison were expiring. This resulted in a flood of companies producing internal horn acoustic phonographs and a number recorded and pressed shellac records as well. During the 1910’s the demand for phonographs and records exceeded the supply; it was logical to enter this lucrative market. Although most did not last long, by the early 1920’s there were over four hundred brands of phonographs on the U.S. market; most were limited in production and distribution. Most had reproducer shells of copper or brass which were electroplated with a thin layer of nickel or gold. A few had shells made of aluminum; some used pot metal. Various methods were used for pivoting the stylus bar, but there were two main types: the knife-edge or point controlled by springs, and the screw-point suspension, which is without springs and is simpler and, if properly adjusted, is practically frictionless. Most companies used thin mica discs for reproducer diaphragms, including the major companies, Victor, Columbia, Brunswick, Aeolian-Vocalion, Pathé, and Sonora. A few of the off-brands that used mica diaphragms were the Empire, Fletcher, Independent, Mutual, Perfection, Scotford, and Superior brands. Some companies used diaphragms made of celluloid, composition, cork, fiber, glass, gutta-percha, metal, rubber, silk, or wood.
Composition diaphragms had varying components, which were not usually revealed. Many may have been cloth or paper treated with shellac or varnish. The Acme, Audion, Blood, Invincible and Paddack brands had reproducers with composition diaphragms. The Bliss reproducer had a taut silk diaphragm; the fabric was stretched nearly to its elastic limit. A stiffening disk of smaller diameter was glued onto the silk; the disc was composed of compressed paper. The spruce diaphragm was made of a thin disc of spruce wood. Spruce is a soft wood with an even grain which makes it useful for constructing musical instruments. The Phon d’Amor reproducer featured a wooden diaphragm, which was not described or identified. The Cheney and Crystola companies had diaphragms made of gutta-percha, which is a tree resin with properties between a rubber and a hard resin. It is collected from the Palaquim and Payena trees which grow in Malaysia; similar to rubber, gutta-percha can be vulcanized and molded into various shapes.
The Cheney diaphragms were molded to form a pattern of three concentric rings; the visible outer side of the diaphragm was painted with a silver or gold-like paint to match the plating on the hardware of the reproducer. The Crystola reproducers had a large ribbed pattern as part of the molded shape of the diaphragm. Crystola did not attempt to change the color of the black gutta-percha. With time the gutta-percha diaphragms have hardened and are not nearly as compliant as when new; little can be done to make the original diaphragms more compliant. The Keen-O-Phone reproducer had a thin aluminum diaphragm with a pattern of concentric rings pressed into the metal; some later Rex talking machines have been found with the same or similar aluminum diaphragm, although the one Rex machine I have seen had a mica diaphragm. The Gloria Phonograph Company had a spun aluminum diaphragm. For a time in the United Kingdom, the Cliftophone gramophone had a composite diaphragm which incorporated a grille mesh of thin metal wires. Later Cliftophone used a diaphragm of thin celluloid. A number of devises were developed and advertised as diaphragm “clamping” or “mute” devices, such as the Jewel Company’s Blood reproducer, the Crippen Company’s “Radio” sound box, and the Phono-O-Mute made by Paddack Products, Inc.
Today there seems to be little interest or demand to develop diaphragm replacement materials. Thin mica and metal diaphragms are still available from the dealer/repairmen on a limited basis. Some collectors are on the lookout for potential replacements and will test varying items including Mylar sheets, plastic lids and liners, shellacked or varnished parchment papers, Styrofoam, and even modern glass. Materials for forming gaskets are sometimes a matter of debate. Some prefer the original-type thin rubber gaskets or rubber tubing, while others claim the semi-solid gaskets formed from various gasket-in-a-tube products to be the best.
In November of 1925, when the Victor Talking Machine Company introduced the Orthophonic Victrola, the new and improved sound box had a thin aluminum diaphragm which was capable of greater “push and pull” in order to play the new electrically recorded records which had not only more volume but much expanded fidelity over the earlier acoustically recorded records. Metal is much cheaper than mica and it is easier to form into large numbers of diaphragms. Metal diaphragms could be made paper thin and with less inertia; they did not impose as much strain upon the walls of a record. Metal diaphragms had a die-pressed rigid center within concentrically corrugated ridges or rings. The central cone or dome was usually bowl-shaped so that it could vibrate as a unit. Increased compliance of the stylus was achieved through the use of ball-bearing support. One disadvantage is that the metal diaphragm is easily buckled or bent out of shape. It is thin and vulnerable; the slightest pressure on the stylus while hastily inserting a needle can bend the stylus bar. For some “suitcase” portable Victrola models, Victor provided a screen guard on the exposed side of the Orthophonic sound boxes to protect the diaphragm from injury. Most metal diaphragms were molded from aluminum or an aluminum alloy.
The Victor Orthophonic Sound Box
Orthophonic Sound Box with protective screen for Victor portable models.
The stylus ratio of the Orthophonic sound box was established at 1.25. This change reversed the trend to favor higher wavelengths. This explains why bass sounds were now obvious and present and why the new electrically recorded discs sounded strident and harsh when played on any of the millions of old Victrolas, the greater number of which were equipped with mica diaphragm sound boxes.
Many phonograph companies produced reproducers with thin stamped aluminum diaphragms copied more or less from Victor’s model. The patterns and shapes of diaphragm centers and the concentric corrugations varied considerably. Most had stylus bars pivoted between two conical bearings; there was no spring tension and adjustment consists of just the right amount of friction in the pivots. A number of phonograph accessory producers offered new Orthophonic-type reproducers which could be had with a variety of fittings for all makes of new and old phonograph models. Many “phonic” reproducers were advertised in the Talking Machine World issues from 1926 to 1929:
Apollo Reproducer: Superior Phono-Parts Company, 799 Broadway, New York City, New York
Carryola Superphonic Reproducer: Carryola Company of America, 647 Clinton Street, Milwaukee, Wisconsin
Guarantee Talking Machine Company, 35 North 9th Street, Philadelphia, Pennsylvania
Mutual Phono Parts Manufacturing Company, 149-151 Lafayette Street, New York City, New York
Oro-Phone: Oro-Tone Company, Department A, 1010 George Street, Chicago, Illinois
Remington Super-Harmonic Sound Box: Remington Manufacturing Company, Bridgeton, New Jersey
Symphonic Reproducer: Symphonic Sales Corporation, 370 Seventy Avenue, New York City, New York
Toman Reproducer: E. Toman & Company, 2621 West 21St Place, Chicago, Illinois
Triumph: Samuel Eshborn, 65 Fifth Avenue, New York City, New York
ULTRA-phonic: Audak Company, 565 Fifth Avenue, New York City, New York
Valphonic: the J. A. Fisher Company, 730 Market Street, Philadelphia, Pennsylvania
Vita-Phonic: Joseph E. Rudello, 83 Greene Street, New York City, New York
It was sad to consider the millions of old phonographs and Victrolas in homes across America which were suddenly obsolete sound reproducing instruments, despite the elegance and high quality of the mahogany, oak, and walnut wood cabinets. Many families attempted to “upgrade” the old family phonograph by installing one of the new “phonic” reproducers which were advertised—more modern reproducers with a metal diaphragm in order to better reproduce the volume and fidelity of the new electrically recorded records. Eventually many old phonographs and Victrolas were moved into storage in the attic, basement, or garage. By the 1940’s they were often relegated to the level of toys for children who enjoyed winding and over-winding the spring motors. One collector claimed he rescued the old family Pathéphone, which he found stored in a chicken coop. It is not unusual to come across an empty phonograph cabinet; the metal parts may have been donated to the metal drives held during World War II.
The earliest Orthophonic sound boxes made in 1925 and 1926 had shells made of brass. However, during 1926 Victor resorted to using pot metal shells and back plates. Restoring the later Orthophonic sound boxes can be difficult and many collectors (and repairmen) will not attempt major repairs. Often the magnetized ball bearings are corroded and the needle bar may be coated with rust. The gaskets may have disintegrated. The shellac used to seal the spider feet has hardened and the diaphragm may have oxidized. Thus the aluminum or aluminum alloy diaphragm is no longer as compliant as when new. The sound box may produce distorted sounds or even rattling noises. When the diaphragm offers too much resistance to the record grooves, not only is the sound quality affected, but damage can be done to the records, no matter what type of needle is used. Often the pot metal shell and back plate are warped and possibly cracked. It is not unusual for a back plate to shatter when attempting to remove it from the shell. Still, a restored Orthophonic sound box can provide amazing sound reproduction, especially when used on one of the larger Orthophonic floor model Victrolas with the large re-entrant type of internal horn. For best sound reproduction the sound box should be designed to have the diaphragm air tight with no holes and no air leaks around the diaphragm mounts. There should also be no air leaks for the tone arm and horn connections and the horn should have no air leaks until the open end.
Mr. James Goodall
Mr. James Goodall of Fife, Scotland, spent a large part of his life studying and listening to disc records and gramophones, both acoustic and electric. Mr. Goodall died on December 25, 1993, at the age of 82. He was endowed with special talents which led him to become an expert restoring and “tuning” gramophone sound boxes. During the 1970’s he wrote of series of articles for The Hillandale News, “The Body and Soul of the Gramophone (The Case for the Defense of the Clockwork Acoustic).” Part five of the series was devoted to diaphragms (No. 104, October, 1978). He observed that while the sound box is a simple mechanical device, the technical factors controlling its performance are numerous and complex. Optimum reproduction depends on matching the shell, diaphragm, gaskets, and needle. His efforts were directed to eliminating “chatter” and wear on records, and the desire to achieve ever better sound reproduction. He found that mica diaphragms should be around six-thousands of an inch thick and he preferred to use solid rubber gaskets, although he also made gasket rings of thin polyethylene tubing. For best results the pressure on the gaskets should be slightly more than the minimum necessary to exclude air gaps between the gasket and diaphragm. He found that a diaphragm with too much compliance will tend to absorb some of the sound rather than pass it on and could also cause an imbalance sufficient to damage the record. If the diaphragm is too stiff it will not respond properly to bass notes and can tend to cause the needle to jump the low frequencies and damage the record.
Mr. Goodall often made the distinction between “collectors” and “listeners.” He also made the observation that with every new innovation in sound recording and reproducing, we seem to be losing an important connection to the original source of the sound. A compact disc disappears into a small box and at best through a small window we may see a fast-spinning small disc. A needle or stylus tracking a record groove may not be the same as the original artist(s) singing or playing, but it is not as far removed. Mr. Goodall speculated that acoustic machines were never developed to their full potential before electronic technology swept them away and he wondered if cheap quality or bad sound boxes hastened the demise of the acoustic gramophone. The various brands of sound boxes and their fittings were never standardized. While diaphragms varied in diameter from 40 millimeters (1.57 inches) upwards, most standardized the diaphragm at 50 millimeters (1.97 inches). Nothing appears to be gained by exceeding 65 millimeters (2.56 inches). He was of the opinion that mica diaphragms had a slight edge over most of the metal diaphragms provided that the mica is set in a sound box that is finely adjusted and well tuned and in which the gasket has the right consistency. He personally preferred the sound quality of the H.M.V. No. 4 sound box as he felt that it provided the best tonal range and balance.
The No. 4 sound box was first issued in England where it won high praise; it has a freely-pivoted stylus bar and the large mica diaphragm is 2 ¼ inches in diameter. Victor made the No. 4 available in January, 1927. Victor recommended the No. 4 as a replacement sound box for the older Victor talking machines and pre-Orthophonic Victrolas. The No. 4 sound box was also used in the Model 1-70 table top Victrola and in several of the Victor portable models. For listeners who found the Orthophonic sound boxes to have too much brilliance and volume, the No. 4 was the recommended replacement. The No. 4 does not recover and reproduce sound vibrations as completely as the Orthophonic sound box, however some listeners disliked the metallic qualities of the aluminum diaphragms. The earliest No. 4 sound boxes came with a brass shell, but most are pot metal which has not aged well; it is not unusual to find a No. 4 with the shell and back plate falling apart.
In March of 1980 Mr. Goodall was invited by Douglas Fitzpatrick to visit him at his home in Sheringham Hall in Norfolk to hear his legendary gramophone which was one of the largest private gramophones ever made. The wood horn was 24 feet long from sound box to the open end, which measured 8 feet wide by 5 feet high. It took Mr. Fitzpatrick four years of trial before developing the final design. At one point the horn went into the floor where it curved gradually upward and re-emerged further back. While several different sound boxes could be used to play the giant gramophone, Mr. Fitzpatrick used an E. M. Ginn sound box with the original aluminum diaphragm replaced with a plastic diaphragm from an American brand stethoscope. Mr. Goodall found the giant gramophone to have very impressive sound quality; it was astoundingly clear and natural with the audible frequency ranges well balanced without stridency and with fine definition. Bass sounds came through in fullness and without “boom” effects. Mr. Goodall spent several days listening to the giant gramophone and was able to test several sound boxes and different types and sizes of needles. He played both acoustic and electrically recorded records. (Hillandale News, “The Big Daddy Of Them All”, No. 155, July, 1980.)
Mr. Lumière was developing this design when World War I intervened. After the war he completed the invention and placed it in the hands of the Gramophone Company, Ltd. In early designs the “sunburst” pattern diaphragm was positioned horizontally; later designs had the diaphragm positioned vertically. The diaphragm was mounted and held between two flat metal rings; the pleated diaphragm was fourteen inches in diameter. A wooden rod or bar conveyed the vibrations from the needle-holder to the center of the diaphragm. The diaphragm and connecting rod could be folded to enable the lid of the gramophone to close. The Gramophone Company developed both table and floor Lumière models. It was first sold in the autumn of 1924 and was available until 1927. Sales were not high and there was a marked lack of enthusiasm from gramophone purchasers. The large exposed paper diaphragm was susceptible to damage or could be distorted by excessive moisture, although some expensive models featured a gilt Lumière diaphragm. Still, the sound produced had a marked absence of distortion and was reported to be, “…particularly pleasant to the ear.” The Lumière models were not sold or produced in the United States.
The Pathé Actuelle phonograph was introduced by the Pathé Phonograph Company in the November 15, 1918 issue of the Talking Machine World, although models were not available until 1920. Similar to the Lumière, the Actuelle does not have a reproducer, tone arm, or horn. It consists principally of a large cone-shaped parchment diaphragm fitted into a large circular aluminum frame. The center of the diaphragm is connected by a metal rod to the needle holder. The sound vibrations from the record are transferred through the rod and the vibrations are released in the form of sound directly from the diaphragm. Exposed metal parts are gold plated. A twist of the needle holder and the horn
frame permits the playing of either vertical or lateral-cut shellac records. Although not outstanding, the sound reproduction from the Actuelle cone is very good with the sound not as directional as coming from a horn. The public was not impressed and the Actuelle models did not have high sales; they are rare today. The parchment cones are delicate and it is not unusual to find the parchment damaged or missing and often replaced with a substitute paper or parchment material. The Pathé Company was at the same time selling Pathéphones with the traditional reproducer, tone arm, and internal horn.
Model H Actuelle
The Polly Portable
The Polly Portable was another phonograph with a parchment cone. Patented in 1922, the Polly Portable Phonograph Company advertised the Polly Portable in August, 1925. This convenient portable was less than a foot square, only 21/4 inches thick, and weighed 8 lbs. It featured a sliding tone arm with a cone-shaped parchment or paper diaphragm called an “oscillator” for playing records. A simple needle holder was positioned at the center of the cone. The cone was designed to fold for storage in the lid. A separate non-folding oscillator was available for home use. In February, 1927, the Brunswick-Balke-Collender Company introduced the same model as the “La Parisian” portable. Now Made by the Allen Hough Manufacturing Company, of Milwaukee, Wisconsin; it was not a Brunswick product. It was identical (except for trademark decals) to the Polly Portable. Two La Parisian models were available, one with a leatherette case for $15.00; the other a figured metal case of dark mottled gray for $10.00.
The Stroh Violin
The Stroh violin has an aluminum diaphragm; the vibrations of the strings are conducted by means of an ordinary violin bridge, which rests upon a rocking lever, to the diaphragm. The lever supporting the bridge oscillates laterally upon the body of the instrument, the end being attached to the diaphragm by a small connecting link. The diaphragm is held in position between two rubber gaskets by means of a specially designed holder fixed upon the body of the violin by two brackets. Attached to this holder is the horn which directs the sound waves forward. The diaphragm freely vibrates and was designed to direct the violin’s sound waves forward for the early recording horn. Despite the unusual appearance of the Stroh violin, the sound quality of the horn is not “metallic.”
The E. M. Ginn
The development of custom-made phonographs, designed to produce the best possible sound without regard to appearance, was an interesting phenomenon of the latter 1920’s, especially in the United Kingdom where interest in mechanical phonographs extended well into the 1930’s. In 1924 E. M. Ginn’s first machine, the Magnaphone, appeared; it was shortly re-named the E.M.G. Handmade Gramophone. Over the years the E.M.G. evolved, acquiring new sound boxes and larger horns. Typically the E.M.G. sound boxes had an aluminum diaphragm. The pointed hook-shaped stylus bar springs and the rubber washers on the screws attaching the shell to the back plate provided for “tuning” by adjusting gasket compression and the distance between the diaphragm and back plate. The sound reproduction of the E. M. Ginn models has become legendary; today the E. M. Ginn gramophones and sound boxes are much sought by serious collector/listeners.
The earliest radios and crystal sets used ear phones for listening. When vacuum tube amplification became available, radios could power a small driver which could be connected to an external horn or to the horn in an acoustic phonograph. Early radio/phonograph models were designed to have a direct current radio driver attached to the tone arm in place of the reproducer when radio reproduction was desired. Soon models were designed with a driver attached to the small end of the internal horn and an external knob to control a “radio/phonograph” valve in the throat of the horn. Termed a compression speaker, a radio driver is similar to a telephone receiver. Although designs varied, output wires from a radio receiver (with vacuum tube amplification) are connected to the terminals leading to the coils surrounding the pole pieces of a permanent magnet. A thin iron or iron alloy diaphragm is placed in close proximity to the magnet. The electric currents generated by the radio correspond to the musical and vocal sound waves coming from the broadcasting station. The electric currents cause a strengthening or weakening of the magnetic pull on the diaphragm which vibrates and generates the sound. A potential problem, the diaphragm is easy to “saturate” with too much magnetism which can cause distortions of the signal. Some upright floor model phonograph cabinets were modified with the addition of a radio which was held in a pull-out drawer below the horn chamber and above a few shelves for record albums. Console floor model phonographs could have the radio installed at the left (facing) side of the cabinet. Early direct current radios required “A,” “B,” and “C” batteries and small UX-199 vacuum tubes for radio wave amplification. Early radio reception was often unsteady with station “drift” and “blast” by more powerful stations; this required the listener to frequently turn the large dial knobs to tune the desired station. A long wire antenna was also needed; the antenna could be wound around a frame. Radio/phonograph models were designed with compartments at the back of the cabinet to hold the “A” and “B” batteries. Soon plug-into-the-wall AC battery eliminators and battery chargers were developed and advertised as accessory items by several companies.
Parchment Cone Speakers
Developed in the mid-1920’s, large parchment cone speakers were modified radio drivers and considered “natural” speakers as their design was better than horn speakers for reproducing larger wavelength sounds. From the iron diaphragm positioned over the magnet, a metal rod or bar connected to the center of the parchment cone. These speakers were convex in shape; they could be as large as twenty inches in diameter. A number of brands were available. The exposed parchment cones, however, were easy to damage and could be affected by too much moisture; they are rarely found in excellent condition today.
By 1926, alternating current radios were available; these could use standard house current. The use of rectifiers could convert the alternating current into direct current as needed in the radio electronics. Moving coil loudspeakers were developed and performed better than radio drivers. In 1928 the screen grid vacuum tubes were introduced; they greatly improved vacuum tube performance. Single dial control radios became the standard.
Most common loudspeakers use a concave paper cone supporting a voice coil electromagnet acting on a permanent magnet, although many other types exist. Many modern sound systems utilize multiple loudspeakers, each a different size and reproducing a different part of the audible sound frequency range, such as different size woofers and tweeters. Moving coil loud speakers often have the paper cones with corrugations in the design. Corrugating extends the audible range and enables the cone to respond to greater physical movement (i.e. dynamic range). Corrugating also helps to preserve symmetry and to give rigidity to the cone. Some cones are made of fine linen paper which is treated to prevent changes due to moisture or temperature. Speaker cones usually have a skeleton frame of metal which is ribbed to give support. The Oxford Dynamic Speaker advertised in 1929 claimed the cloth cone was metalized, one piece, puncture-proof with a controlled edge, and had three-point suspension.
Restoring the electronics of the early AC radio/phonographs can be difficult. Early radio collectors and restorers can usually be the most help and can even provide a photocopy of the electronic schematics for most models. A restored early radio/phonograph can have excellent sound reproduction.
REPAIRING THE VICTOR EXHIBITION SOUND BOX