Tom Danley | |
---|---|
Born | July 16, 1952 |
Occupation(s) | Audio engineer, electrical engineer and inventor |
Employer(s) | Intersonics, Danley Sound Labs |
Children | 2 |
Website | http://danleysoundlabs.com |
Thomas J. Danley (born 1952) is an American audio engineer, electrical engineer and inventor, the holder of multiple patents for audio transducers, especially high-linearity, high-output professional horn loudspeaker systems. Danley first gained notice in the 1980s with his novel servomotor-driven subwoofer systems used to reproduce very low frequencies in concert tours and theme parks. In 2000 he advanced the implementation of multiple-entry horns in 2000 with several designs led by the SPL-td1, a seven-driver loudspeaker. In 2005, he started a new company, Danley Sound Labs, through which he patented further technologies and produced a wide variety of loudspeaker models based on these technologies.
Danley was raised in the northern area of Illinois, around Highland Park, north of Chicago. His father and brother were mechanically inclined, and taught Danley how to use the workshop tools. Danley studied mechanisms by taking them apart, and he learned to arc weld by age 12. [1] He attended Deerfield High School, obtaining his diploma in five years instead of four. [2] [3] He later said, "I took every shop class there was, but I had an attendance problem and math was my weakest thing." [1] One of his friends from mechanical drawing class was T.C. Furlong, who later became an equipment manufacturer and event production company owner. [4]
During and after high school, Danley worked as an electronic technician, and he played bass guitar in several bands. He fabricated his own tube amplifiers. After a few years, he joined Steamer Sound, the audio production company founded in 1973 by Furlong. Danley designed loudspeakers for the company, and for individual musicians such as keyboardist Joan Gand. [4] In 1974, he brought a reel-to-reel tape recorder to the Alley, a nightclub in Highwood owned by Furlong, to record the performance of the John Burns Band (the son of Jethro Burns) as he mixed their set. Danley was amazed when he listened to the tape after the show; the tape held a wider frequency range, a higher fidelity experience than was heard at the nightclub. He realized that the loudspeakers must have been a significant limiting factor. [1]
Danley left Steamer Sound to work as an electronics technician at Data Specialties in Northbrook, where in 1976 he first used a computer, a VIC-20, to write a program to perform the math calculations he needed at work. [1] He was repairing teleprinters and punch card readers, and had almost given up on concert audio in his career. [2]
In 1979, a co-worker recommended a job offering nearby at Intersonics, a contractor to NASA, supplying hardware for rocketry research. [2] Danley invented many devices while at Intersonics, obtaining 17 patents. The inventions include a high-powered acoustic levitator, a sonic-boom generator used by BBN Technologies, and a multi-enclosure Flow Modulator loudspeaker system used by Georgia Tech Research Institute and NASA for vibration tests on rocket payloads. [1] Danley designed and built major components of the payload on Space Shuttle flights STS-7 in 1983 and STS-51-A in 1984. [5]
Danley experimented on his own with a loudspeaker based on the servomotor, and showed the third prototype to his employer. When he asked permission to use this technology to create a subwoofer product line for concerts and touring sound systems, Intersonics president Roy Whymark said yes, but only if the effort did not interfere with Danley's other responsibilities at Intersonics. [2] Danley designed a variety of models including W bins, seeing the most success with the folded horn BassTech 7 subwoofer which performed very well. ServoDrive became the professional audio division of Intersonics.
The BassTech 7 was used to great acclaim by Clair Brothers on the North American legs of Michael Jackson's Thriller tour and U2's the Unforgettable Fire tour, both in 1984. [6] Clair typically used a dozen Danley subwoofers as the lowest element of a 5-way system, to fill the bottom octave. Other large purchasers of the BassTech 7 included Disney with about 500 units in Europe and the U.S., and in Las Vegas, the hotels Mirage and Treasure Island which used the BassTech 7 for special effects. The BassTech 7 drive unit was essentially a cube holding two opposing 15-inch woofers, both connected to a central servo motor by way of shafts and flexible belts. The enclosure included Danley's patented cooling fan powered by a DC-rectified portion of the audio signal, kicking in only at high voltage levels. The servo motors in the subwoofer allowed for 3 to 4 times as much peak-to-peak deflection of the woofer cones, compared to what was available at the time with conventional magnetic coil woofers. Additionally, the servo design greatly reduced the common problem of power compression, in which a driver heats up and sound output drops. The servo motor can change direction very quickly, easily allowing an upper frequency response of 125 Hz down to 28 Hz with less than 2% harmonic distortion. [7] Trouble arose with the belt material, which was modified several times by the supplier without notice, resulting in driver failures.
Both Intersonics and the ServoDrive division grew in the mid-1980s. A turning point was the Space Shuttle Challenger disaster in 1986, which damped the mood and the business climate in the aerospace industry, and brought delays and cancellations of contracts. [2] [3]
Around 1986 a request came in to Intersonics from Cornell University for a low frequency subwoofer loudspeaker intended to reproduce elephant vocalizations in Kenya. Dr. Joyce Poole and Katy Payne of the Amboseli Elephant Research Project asked for a custom loudspeaker that would fit inside a sport utility vehicle, and provide strong output down to 14 Hz. Danley designed the Pachyderm 6, [8] an enclosure with two 15-inch drivers connected to a servo motor, and four 18-inch passive radiators. The output at 14 Hz was measured at about 115 dB with about 200 watts from the amplifier. [9]
Based on this, another subwoofer model produced by ServoDrive was the Contrabass in 1987, similar to the Pachyderm 6 but with a smaller enclosure and half the number of passive radiators. The frequency response also reached down to 14 Hz. The Contrabass was popular for home theater installations, including George Lucas' home. [9] An unusual characteristic of the Contrabass was that its distortion components went down as sound pressure level went up, until 105 decibels was reached. [8]
Intersonics determined to close the ServoDrive division, as it was considered a distraction from aerospace work. To save the firm, Danley teamed with Bradford Skuran, a guitarist he had played with in his youth, to form a new company: Sound Physics Labs (SPL). SPL bought ServoDrive and continued to produce and service the subwoofers, as well as to design new loudspeakers.
In the late 1990s, Danley designed the SPL-td1, his first trapezoidal "top box" intended to deliver the mid- and high frequency sounds to complement a subwoofer. The SPL-td1, produced in 2000, was a 3-way speaker which used seven drivers exiting into the same horn to deliver greater coherence. The SPL-td1 was used in many installations and concerts, including the opening and closing ceremonies of the 2002 Winter Olympics in Salt Lake City. Danley's 3-way design was an improvement on the 2-way CoEntrant patent by Ralph Heinz in 1996. [10] In 2001, Danley began developing the "Unity" horn for license to Yorkville Sound, patenting the improvement in 2002. [11] In 2003, Yorkville released their Unity line of loudspeakers, using Danley's Unity horn design for the mid-range and high frequency bandpasses. [12]
Further modifications to the SPL-td1 concept came with the SPL-td2 providing improved phase/time linearity, the smaller and lighter SPL-runt, and the larger SPL-trik containing nine drivers.
In the early 2000s, Danley was participating in online discussions at Dave Stevens' Live Audio Board (LAB), a bulletin board system which was later hosted by ProSoundWeb. A number of LAB users wished to collaborate on a do-it-yourself (DIY) subwoofer design. Danley discussed the benefits and tradeoffs of horn versus front-loaded subwoofers, and offered to model a horn enclosure based on the desired size, frequency response and power handling. He "spearheaded" the effort which in February 2002 resulted in Danley posting the design of a 45 in × 45 in × 22.5 in (114 cm × 114 cm × 57.1 cm) snail-shell folded-horn subwoofer using two 12-inch drivers at the horn throat. [13] [14] [15] (This was the exact same enclosure size as the BassTech 7, with similarities in the internal folding of the horn.) Eminence, an American speaker company who was also participating in the discussions, designed a custom 12-inch driver to meet the requirements: the LAB12. The LAB Sub, also called the LAB horn, was a heavy subwoofer optimized for operation as four enclosures strapped together in a 2×2 "cube" configuration, to increase the effective mouth size and achieve a low frequency of 32 Hz. Danley's conceptual design (he never built one) was given freely to the public domain, and proved to be influential as the first DIY folded horn subwoofer. [16]
Danley partnered with entrepreneur Mike Hedden in 2005 to form Danley Sound Labs (DSL), a loudspeaker company based in Gainesville, Georgia, near Atlanta. Previously, Hedden had been the owner of dB Audio & Video, an A/V contractor who was the largest distributor of SPL loudspeakers. For the first ten years of DSL, Danley contributed design ideas while continuing to live in Illinois. In 2015, he moved to Georgia. The first product was the SH100, an 8-inch coaxial loudspeaker intended for 300-seat churches. [17]
Danley's Synergy Horn concept was an improvement on the multiple entry design of the SPL-td1. The idea is that multiple drivers in different bandpasses are combined into one horn to make a phase-accurate, constant-directivity single-point-source loudspeaker.
Danley's Tapped Horn concept directs sound from the rear of a horn-loaded driver into ports (taps) that are vented into the horn closer to the mouth of the horn, farther from the driver at the throat of the horn. At frequences such that the wavelength is twice the distance to the taps, the waves routed inside the cabinet to exit through ports in the horn combine positively with direct sound from the front of the driver.
Following the SH100, the SH50 was introduced: a 3-way, seven-driver loudspeaker, launched in November 2005. It used both the Synergy Horn and the Tapped Horn technologies to deliver coherent sound down to 50 Hz with an output pattern of 50° × 50°. [18] [19]
Danley's Shaded Amplitude Lens technology, patented in 2009, uses vanes to deflect portions of the high frequency driver output so that the different paths produce an output pattern appropriate for large venues, such that the farther audience hears much the same amplitude and sound fidelity as the near audience. The vanes allow the upper output pattern of the horn to be narrower than the angle of the horn walls, to carry farther without dissipating. The lower parts of the horn allow the sound to spread wider for the near audience. [20]
In 2011, Danley filed a patent for DSL's Paraline Technology, a method of combining the output of multiple high frequency drivers into a common output chamber or horn. The waves are routed through multiple passageways defined by parallel partitions of gradient sizes. [21]
In March 2007, DSL produced the Matterhorn, a single subwoofer made from an intermodal shipping container. Danley designed the Matterhorn to meet a military specification, to produce a low frequency sound in the range of 15 to 20 Hz, to be measured at 94 decibels at a distance of 250 meters. To accomplish this, Danley arranged forty 15-inch MTX subwoofer drivers in a tapped horn configuration, each driver powered by its own 1,000 watt amplifier. A diesel generator was included inside the container for operation in the field. [22] The subwoofer has a flat frequency response from 15 to 80 Hz, and is down 3 dB at 12 Hz. [23] [24] The Matterhorn has been called the World's Biggest Subwoofer. [25]
In 2010, DSL introduced the Jericho Horn, a loudspeaker intended for large audiences. The Jericho Horn is a 4-way design employing six 18-inch drivers for the lows, six 6-inch drivers for the low mids, and two mid-high frequency drivers each of which carries 2-way high frequencies. The Jericho Horn incorporates Danley's patented Shaded Amplitude Lens technology. [20]
The Jericho Horn was praised in 2017 when four of the large enclosures were used for DJ sets at the Temple stage at Glastonbury Festival, along with 22 boxes of DSL TH-118 subwoofers. The Jericho Horns and subwoofers were installed and operated by Neuron Pro Audio. [26] After hearing the sound system, festival co-founder Michael Eavis chose the Temple stage for his welcome speech rather than the main stage. [27]
Danley has consulted on acoustic issues for various projects. He appeared in the 1993 documentary The Mystery of the Sphinx to demonstrate acoustic levitation. Danley was an early adopter of the Crown Tecron TEF (time-energy-frequency) audio analysis system, introduced in 1983, and he used a TEF-10 portable test rig to measure his audio experiments. At the request of the same documentary producer, in the 1990s Danley used a TEF-12 analyzer to assess the acoustics inside the Great Pyramid of Giza. [1] [28]
In 2019 Danley was recognized as an audio industry pioneer by AVIXA, the Audiovisual and Integrated Experience Association. Danley received the Adele De Berri Pioneers of AV Award. [29] The award was presented on June 12 at the InfoComm convention held in Orlando, Florida. [30]
Danley has played bass guitar since high school. He was in several bands in the 1970s. [4]
When his marriage dissolved in the late 1980s, Danley raised his two daughters as a single father. [1]
A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies known as bass and sub-bass, lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range for a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below 80 Hz in THX-certified systems. Thus one or more subwoofers are important for high quality sound reproduction as they are responsible for the lowest two to three octaves of the ten that are audible. This very low-frequency (VLF) range reproduces the natural fundamental tones of the bass drum, electric bass, double bass, grand piano, contrabassoon, tuba, in addition to thunder, gunshots, explosions, etc.
A loudspeaker is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A speaker system, also often simply referred to as a speaker or loudspeaker, comprises one or more such speaker drivers, an enclosure, and electrical connections possibly including a crossover network. The speaker driver can be viewed as a linear motor attached to a diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the dynamic speaker driver, by far the most common type, is a linear motor in the same basic configuration as the dynamic microphone which uses such a motor in reverse, as a generator.
A woofer or bass speaker is a technical term for a loudspeaker driver designed to produce low frequency sounds, typically from 20 Hz up to 80 Hz. The name is from the onomatopoeic English word for a dog's bark, "woof". The most common design for a woofer is the electrodynamic driver, which typically uses a stiff paper cone, driven by a voice coil surrounded by a magnetic field.
An electrostatic loudspeaker (ESL) is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.
A horn loudspeaker is a loudspeaker or loudspeaker element which uses an acoustic horn to increase the overall efficiency of the driving element(s). A common form (right) consists of a compression driver which produces sound waves with a small metal diaphragm vibrated by an electromagnet, attached to a horn, a flaring duct to conduct the sound waves to the open air. Another type is a woofer driver mounted in a loudspeaker enclosure which is divided by internal partitions to form a zigzag flaring duct which functions as a horn; this type is called a folded horn speaker. The horn serves to improve the coupling efficiency between the speaker driver and the air. The horn can be thought of as an "acoustic transformer" that provides impedance matching between the relatively dense diaphragm material and the less-dense air. The result is greater acoustic output power from a given driver.
Klipsch Audio Technologies is an American loudspeaker company based in Indianapolis, Indiana. Founded in Hope, Arkansas, in 1946 as 'Klipsch and Associates' by Paul W. Klipsch, the company produces loudspeaker drivers and enclosures, as well as complete loudspeakers for high-end, high-fidelity sound systems, public address applications, and personal computers.
A bass reflex system is a type of loudspeaker enclosure that uses a port (hole) or vent cut into the cabinet and a section of tubing or pipe affixed to the port. This port enables the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical sealed- or closed-box loudspeaker or an infinite baffle mounting.
A full-range loudspeaker drive unit is defined as a driver which reproduces as much of the audible frequency range as possible, within the limitations imposed by the physical constraints of a specific design. The frequency range of these drivers is maximized through the use of a whizzer cone and other means. Most single driver systems, such as those in radios, or small computer speaker designs, cannot reproduce all of the audible frequencies or the entire audible audio range.
A loudspeaker enclosure or loudspeaker cabinet is an enclosure in which speaker drivers and associated electronic hardware, such as crossover circuits and, in some cases, power amplifiers, are mounted. Enclosures may range in design from simple, homemade DIY rectangular particleboard boxes to very complex, expensive computer-designed hi-fi cabinets that incorporate composite materials, internal baffles, horns, bass reflex ports and acoustic insulation. Loudspeaker enclosures range in size from small "bookshelf" speaker cabinets with 4-inch (10 cm) woofers and small tweeters designed for listening to music with a hi-fi system in a private home to huge, heavy subwoofer enclosures with multiple 18-inch (46 cm) or even 21-inch (53 cm) speakers in huge enclosures which are designed for use in stadium concert sound reinforcement systems for rock music concerts.
The Isobaric loudspeaker configuration was first introduced by Harry F. Olson in the early 1950s, and refers to systems in which two or more identical woofers operate simultaneously, with a common body of enclosed air adjoining one side of each diaphragm. In practical applications, they are most often used to improve low-end frequency response without increasing cabinet size, though at the expense of cost and weight.
Cerwin-VegaInc. is a brand name used on products for professional audio components, as well as home audio speakers, and car audio components. Originally a stand-alone company, Cerwin-Vega was acquired by the Stanton Group after declaring bankruptcy in 2003.
Acoustic suspension is a method of loudspeaker cabinet design and utilisation that uses one or more loudspeaker drivers mounted in a sealed box or cabinet. Acoustic suspension systems reduce bass distortion that can be caused by stiff motor suspensions in conventional loudspeakers.
An electrodynamic speaker driver, often called simply a speaker driver when the type is implicit, is an individual transducer that converts an electrical audio signal to sound waves. While the term is sometimes used interchangeably with the term speaker (loudspeaker), it is usually applied to specialized transducers which reproduce only a portion of the audible frequency range. For high fidelity reproduction of sound, multiple loudspeakers are often mounted in the same enclosure, each reproducing a different part of the audible frequency range. In this case the individual speakers are referred to as drivers and the entire unit is called a loudspeaker. Drivers made for reproducing high audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers, and those for low frequencies are called woofers, while those for very low bass range are subwoofers. Less common types of drivers are supertweeters and rotary woofers.
A super tweeter is a speaker driver intended to produce ultra high frequencies in a multi-driver loudspeaker system. Its purpose is to recreate a more realistic sound field, often characterized as "airy-ness". Super tweeters are sometimes found in high fidelity speaker systems and sometimes even in home theater systems. They are used to supplement the sound of tweeters by reproducing frequencies which the tweeter may produce only with a narrow polar output, or perhaps with distortion.
KEF is a British company specialising in the design and production of a range of high-end audio products, including HiFi speakers, subwoofers, architecture speakers, wireless speakers, and headphones. It was founded in Maidstone, Kent in 1961 by a BBC engineer Raymond Cooke OBE (1925–1995).
A parabolic loudspeaker is a loudspeaker which seeks to focus its sound in coherent plane waves either by reflecting sound output from a speaker driver to a parabolic reflector aimed at the target audience, or by arraying drivers on a parabolic surface. The resulting beam of sound travels farther, with less dissipation in air, than horn loudspeakers, and can be more focused than line array loudspeakers allowing sound to be sent to isolated audience targets. The parabolic loudspeaker has been used for such diverse purposes as directing sound at faraway targets in performing arts centers and stadia, for industrial testing, for intimate listening at museum exhibits, and as a sonic weapon.
David W. Gunness is an American audio engineer, electrical engineer and inventor. He is known for his work on loudspeaker design, especially high-output professional horn loudspeakers for public address, studio, theater, nightclub, concert and touring uses.
Charles Emory Hughes II is an American inventor and audio engineer. He is known for his work on loudspeaker design, and the measurement of professional audio sound systems. Hughes first worked for Peavey Electronics designing loudspeakers and horns where he was granted a patent for the Quadratic-Throat Waveguide horn used in concert loudspeakers. He worked for Altec Lansing for two years as chief engineer for the pro audio division and was granted two more patents. In 2021, Hughes was hired by Biamp as principal engineer.
A transmission line loudspeaker is a loudspeaker enclosure design which uses the topology of an acoustic transmission line within the cabinet, compared to the simpler enclosures used by sealed (closed) or ported designs. Instead of reverberating in a fairly simple damped enclosure, sound from the back of the bass speaker is directed into a long damped pathway within the speaker enclosure, which allows far greater control and use of speaker energy and the resulting sound.
In a loudspeaker, power compression or thermal compression is a loss of efficiency observed as the voice coil heats up under operation, increasing the DC resistance of the voice coil and decreasing the effective available power of the audio amplifier. A loudspeaker that becomes hot from use may not produce as much sound pressure level as when it is cold. The problem is much greater for hard-driven professional concert systems than it is for loudspeakers in the home, where it is rarely seen. Two main pathways exist to mitigate the problem: to design a way for the voice coil to dissipate more heat during operation, and to design a more efficient transducer that generates less heat for a given sound output level.