The History Of Hartley Loudspeakers
Founded in 1927, by H.A. Hartley in London, England, Hartley coined the phrase "high fidelity". This was a noteworthy beginning for a company who would innovate and change the face of the loudspeaker industry forever.
Hartley, with engineer P.K. Turner and ideas from Barker, Voigt, and Olson set out to manufacture speakers, preamps, amps and to establish an association with record players and phono cartridges. Most noted were the speakers – the model 215 full-range driver and an ingenious cabinet design called the Boffle. The Boffle (a cross between box and baffle) was the world's first attempt at acoustically eliminating the driver's rear wave. The inside was a series of panels with acoustic materials stretched over frames that had descending and ascending center holes.
Hartley became an exporter and in 1949 opened an office/installation facility in New York City owned and operated by Robert Schmetterer. With the assistance of Piers Powell, a noted writer for The London Times, the New York office set up retail and distribution channels throughout the USA. A prominent New York cabinet designer was retained to help innovate elegant furniture to house the Hartley drivers.
As the U.S. distributor was flourishing, founder H.A. Hartley decided to sell the rights to the company but maintain a working relationship with the U.S. facility. In 1953, Hartley Products Corp. of New York (the new American company) was established, owned and operated by Robert Schmetterer. The decision was made to manufacture speakers ONLY. However, Hartley Products Corp. was appointed the the first U.S. distributor of Ferrograph (mono) reel-to-reel tape recorders.
In 1958 H.A. Hartley published his most famous book, "The Audio Design Handbook". This book covered aspects of acoustics, electronic technology (tubes), speaker and cabinet design to name some of the many topics.
A few years later a most important association was established – the retaining Dr. Harold Luth, a scientist extraordinaire with a background in a number of disciplines: physics, acoustics and chemistry. His expertise led to the development of the world's first synthetic cone material, a unique control system, "magnetic suspension," and one of the first true coaxial speakers. Patents were soon forthcoming in the early 1960's. In 1967, the younger Richard Schmetterer joined the firm as Vice President and soon began designing drivers, enclosures and crossovers. Some 40 plus years later, Hartley Loudspeakers, Inc. is still hand-crafting speaker drivers with the same integrity of years past and is supplying the U.S. and international markets as well.
By the late 1960s, Hartley was a well-known name in the audio industry. Their electronics were mostly forgotten by then, and the company's own loudspeaker system (drive-units plus a cabinet) designs didn't made a lasting impression on much of anyone. But Hartley's drivers were a hit with audio tinkerers and sound-reinforcement specialists alike, and their promotional materials from that era leave little doubt that Hartley had a younger audience in their sights than their competitors did. AR had Miles Davis and Bose had Jonathan Livingston Seagull, but Hartley had the hippest ads and brochures of all: high-contrast black-and-white photos with lots of text, written with technical authority and dry wit in fairly equal measures. Volkswagen made history with ads like that — and so, in a smaller way, did Hartley.
But as the years wore on, and as magazines such as Stereo Review and High Fidelity began sucking the life out of our hobby by promoting the quest for good sound as little more than a numbers game—one in which a new breed of mass-market manufacturers had a built-in advantage—it became clear that the hi-fi industry could no longer continue as it was, and that most American companies would have to choose between shrinking and selling out. Hartley chose the former path, and, under the direction of Richard Schmetterer, who took over from his father in 1978, the company began to trim its product line. In 1986, the company moved away from the New York metropolitan area to a smaller manufacturing and sales facility in Wilmington, North Carolina, with Richard Schmetterer still at the helm.
We spoke to Richard Schmetterer in January 2021, who informed us that Hartley Loudspeakers Inc, ceased production around 2015.
THE HARTLEY POLYMER LOUDSPEAKERS
In the past, very spl people have known about HARTLEY speakers. Audiophiles, engineers, musicians, recording technicians, scientists and other professionals who use sound or consider sound to be a very important part of their lives or careers. No matter what the price, HARTLEY speakers are considered among the best available anywhere in the world. Meticulous hand-crafting and unique problem solving of the physics of loudspeakers are the reasons for our long standing reputation. We don't sell a lot of speakers that way, but we don't have to compromise our standards either. In fact some of our drivers require over fifty hand operations to build.
Only in recent times do we find companies using cone materials other than paper: polypropylene, kevlar, aluminum, synthetic polymers and other plastic formulations to name a few. Their more recent revelations was our understanding over FIFTY years ago! Starting with polmerization to paper cones, in 1956 Dr. Harold Luth, chief engineer and Master Chemist developed the World's First Synthetic Loudspeaker Cone. Until that time the only non-paper cones were that of bakelite paging speakers used by the Navy. To accomplish this truly revolutionary feat Dr. Luth had to invent a new synthetic to which the world had never seen. A series of monomers cross-linked became the solution which led to other problems and solutions. Platos' loudspeaker cone is one that has: no mass, infinite stiffness, perfect geometry and ultra-fast sound transmission time. Dr. Luth choose a molding process with a special fabric carrier and internally molded ribs. With his physicist hat on (and pipe) he designed a superior geometry never before seen. The cones were shallow, incredibly light and stiff and could withstand high molecular pressure without edge noding and bending.
Most speaker driver manufacturers use foam, treated cloth or butyl rubber as their compliant surround. Foam, untreated will deteriorate inside-out from humidity and moisture in the air. Treated cloth is much less compliant, and exhibits more resonances. Butyl rubber a much better choice will break-down due to ozone in the air. The solution Dr. Luth determined due to his extensive background in chemistry was silicone rubber. Totally inert, extremely low resonance, proper durometer, impervious to moisture, as well as UV rays and a lifetime of greater than 99 yrs. Every other manufacturers surrounds are glued to the cone. This can lead to spurious resonances and even separation at the joint. Dr. Luth's solution was to change the chemical mix during molding from polymer to silicone rubber thus eliminating a joint completely. A seemless molding solution!
THE VOICE COIL (MSG Models)
The dual voice coil in the HARTLEY speakers (220 MSG & 207 MSG) is based on a principle first developed by the British physicist, A.C. Barker, in 1938. Barker's "duode" coil consisted of two coaxial windings, isolated by a plastic film. By transformer action, high frequency signals imparted to the copper windings were induced on the aluminum shorted turn. The aluminum tube could move independently of the copper windings to vibrate the speaker cone to which it was connected. Barker's voice coil, although sound in principle, was never fully successful because he was never able to fully isolate the two sets of windings with the materials available at that time. However, developments in synthetic chemistry have enabled us to produce a highly compliant silicone compound, only 4 mils thin, which isolates the windings effectively and permits the inner aluminum tube to move independently at high frequencies. The HARTLEY aluminum tube is a complete circuit not slotted. It should be noted that in the HARTLEY speaker, the aluminum and copper windings are each connected to respective sections of a dual cone. In the Barker voice coil, the aluminum tube was the only part of the assembly fastened to the cone. Electrically, the dual voice coil may be considered an air-cored transformer, modified somewhat by the presence of a small amount of iron on the pole piece of the speaker magnet structure. The copper windings and aluminum tube comprise a voltage step-down transformer, in which the copper turns are the primary and the aluminum tube the secondary. Signals fed to the copper windings of the voice coil are induced by transformer action on the aluminum shorted turn. Because it is a step-down transformer, the induced voltages are lower and the current higher than the primary voltages and currents. Air-cored transformers are quite inefficient at low frequencies. Consequently, the current induced in the aluminum tube begins to drop sharply at 2000cps and virtually disappears at 1000cps. An elegant way of eliminating a crossover with its losses and distortions.
THE HEAT SINK (HS MODELS)
All HARTLEY HS woofers employ a unique "heat sink" which is actually the aluminum tube the voice coil is wound on. The tube is cut so that a significant portion protrudes through the apex of the cone allowing the greatest concentration of heat (around the coil windings) to be dissipated through the tube outside the cone and into the air. During the coil winding a special high temperature epoxy, manufactured by HARTLEY, is applied to all layers of the windings and baked in with a temperature of over 450 degrees F. This extreme temperature far exceeds the rating of the copper wire itself!
In the first HARTLEY speakers in the 1920's our spiders were made out of bakelite and had four legs that were bolted to the magnet structure. The shape defined the name "spider". Today we still employ the same design but with materials to meet 21st Century standards. Spiders for the polymer series are made from tri-laminate fiberglass which is impervious to adverse weather conditions and strong enough to withstand parallel and perpendicular forces.
Most driver manufacturers use stamped steel frames. These stampings are inexpensive but they exhibit unwanted resonances. Ringing is often used when referring to this steel frame. All HARTLEY polymers drivers use a sand-cast aluminum frame, light and strong, inert and then polished. Yes, an expensive way to make a speaker frame.......also the best!