MIT Cables

MIT Cables - Music Interface Technologies is an American company specializing in the creation of hi-fi audio components, also known as high-end audio equipment for audiophiles, recording studios, and the movie industry. Primary products include professional audio cables, video cables, HDMI cables, and AC power filter products used to connect audio and video components.

History

25 years of cable research and technology.

Bruce Brisson - the founder of MIT Cables - is regarded as the person whose designs and patents helped define the high-end cable industry in the 1980's. Mr. Brisson holds the most technology patents for the high-end audio cabling products. In the early 1980’s, Mr. Brisson licensed the Monster Cable Company with his earliest designs. These designs included Monster Cables Interlink Reference, which many regard as the first true high end audio cable, as this cable was the first cable that produced real audible differences when tested against other simple cable products when installed in an audio system. Brisson’s patented technologies define the performance differences between common 'just cable' products, and true high end cable products.

Unique Test and Measurement Abilities

Part 1

A key element that was always missing when discussing the sonic performance of audio cable was the ability to quantify any given cables sonic performance through measurable test results. Brisson had been measuring audio cables since 1976. In 1992, after years of R&D, MIT announced the development of the Efficiency Measurement, a test and measurement program that correlates measureable test bench results with the sonic qualities of cable. Using proprietary software designed by MIT in conjunction with Hewlett-Packard (HP Invent) MIT was able to calculate, an audio cables Efficiency Response via its complex impedance. The complex impedance of any cable or network is defined by (3) three electrical components; (L) inductance, (C) capacitance, and (R) resistance. Each of these electrical components has a value and phase angle associated with it. The audio range is normally considered to extend from 20 Hz. to 20 kHz. The values and phase angles of each component were measured both independently, as well as their complex impedance at various frequencies within the audio range. From those measurements calculations were performed, and a single graph was produced which plotted the cables efficiency across the audio’s frequency range. MIT called this the Efficiency Response of the cable or passive network being measured. The Efficiency Response correlated a cable’s sonic performance to what the ear hears, something no other audio cable company has the ability to do.

Part 2

The transfer characteristics of an audio cable or any passive networks complex impedance, has peaks (highs) and troughs (lows) at various frequencies across the frequency range. These peaks and troughs are also known as poles and zeros. Likewise, MIT’s Efficiency Measurement also shows peaks and troughs, or poles and zeros when measured across the audio range. These poles and zeros of efficiency denote how efficiently the music is being transported through the cable or network. Music being transported at frequencies at or around the zero points of an audio cable will not be heard as loudly, or as vibrantly as music being transported through the cable at the poles of the efficiency response. All cables have at least one pole or a peak in the Efficiency Response when measured across the audio range. MIT calls this a Pole of Articulation. This is because the cable will articulate both speech and music at this frequency with higher integrity than it will at the zeros.

In 1997 MIT once again called on the people at Hewlett Packard. Several meetings took place, and the result was more software was once again written. Additional test and measurement equipment was also purchased at this time. The goal, this time, was to define any and all activity surrounding the poles and zeros that had been previously located with the Efficiency Response measurement. This effort resulted in the Articulation Response Measurement being developed. The Efficiency Measurement was a swept steady state measurement. The Articulation Response is a dynamic measurement using a single step pulse as the stimulus. This project took about two years, and came to fruition in late 1999. With the advent of the Articulation Response Measurement, MIT could now completely define not only how efficiently the cable transported each frequency component through the cable, but also, how fast, or how slow the cable responded to the stimulus at each of those frequencies. This R&D effort resulted in the release of the MIT Oracle Prism in the year 2000. While the Prism was not called a MultiPole product, it was in fact the prototype for all products that would later be badged using the MultiPole technology.

Products
*Professional audio
**MIT patented technology Speaker Interfaces
**MIT patented technology Audio, Video, Power, and Custom Install Products

Patents

MIT Cables has more Performance Patents than any other audio video cable manufacturer

Audio signal cable - United States Patent 4,538,023

An audio cable in which a plurality of outer conductors surround one or more inner conductors. The outer conductors provide a path for the relatively high frequency components of the signal and the inner conductors provide a path for the relatively low frequency components of the signal. The length of each outer conductor is greater than the length of the inner conductors and the outer conductors are wound around the inner conductors so that the frequency components of the signal arrive at the end of the end of the cable at the same time.

High current demand cable - United States Patent 4,718,100

Cabling (10) is provided for interconnecting amplifier (12) having a positive side (14) and a return side (16) to a load (18) having a positive side (20) and a return side (22). The cabling comprises a first open circuited conductor (24) having a first end (26) connected to a selected one of the amplifier positive side (14) and the amplifier return side (16) and having a second end (28) extending towards and terminating free from connection to the load (18). A second open circuited conductor (30) is provided which has a first end (32) connected to a respective one of the load positive side (20) and the load return side (22), said respective one being of a different polarity than the polarity of the selected one of the amplifier positive side (14) and amplifier return side (16) to which the first open circuited conductor (24) is connected and having a second end (34)extending towards and terminating free from connection to the amplifier (12). A first amplifier-load connecting structure (38) serves for electrically connecting the amplifier positive side (14) to the load positive side (20), the first connecting structure (38) being wound about at least a majority of the length of a selected one of the first and second open circuited conductors (24,30). A second amplifier-load connecting structure (40) serves for electrically connecting the amplifier return side (16) to the load return side (22), the second connecting structure (40) being wound about at least a majority of the length of a selected other of the first and second open circuited conductors(24,30). Improved sound results from use of such cabling.

Audio frequency cable with reduced high frequency components - United States Patent 4,994,686

Audio cabling includes a first conductor in conductive communication with the positive side of the source or of the load. It extends towards but terminates free of the load if it is connected to the source and free of the source if it is connected to the load. A second conductor has a first end in conductive communication with the negative side of the source or of the load. If it is connected to the source negative side it has a second end which extends towards but terminates free of the load. If it is connected to the load negative side it has a second end which extends toward but terminates free of the source. The conductors are separated from one another by a non-conductor. They are sufficiently long whereby they are in adjacent side by side relation at least along portions thereof. High frequency noise which can affect the ear's perception of audio frequency signals is reduced as are low frequency resonance effects.

Audio signal transmission system with noise suppression network - United States Patent 4,954,787

In an audio signal transmission system comprising an interface circuit is connected across the output terminals of an audio signal source or across the input terminals of an audio signal transmission cable coupled to the source. The interface circuit comprises either a discrete capacitance or a distributed capacitance in series with a discrete resistor. The value of the capacitance and the resistance in the interface circuit is chosen such that the time constant of the cable with the interface circuit produces in response to noise a signal having a frequency which is above the audio frequency spectrum but within the passband of the amplifier to which it is coupled.

Method & apparatus for reducing attenuation & phase shift - United States Patent 5,123,052

In an audio signal transmission system having a source of audio signals and a load coupled thereto by means of a first and second transmission line, a discrete capacitor is coupled in parallel with one or both of the transmission lines. The magnitude of the capacitor is as large as stable operation of the amplifier to which it is connected will permit.

Audio signal transmission line with low-pass filter (series or parallel inductance) - United States Patent 5,142,252

An audio signal transmission line comprising an additional inductance inserted in series with the line and/or coupled in parallel therewith near the load end of the line for providing a low pass filter which overcomes parasitic and dielectric capacitance of the line so as to reduce audio frequency noise generated in the line by low level and low frequency audio signals. The magnitude of the inductance used may vary widely, e.g. from 20 microhenries to 1 millihenry, depending on the length of the line and the space available.

Critically damped capacitor & method of making same (Multicap) - United States Patent 5,144,522

A critically damped capacitor comprising a capacitance C having in series therewith a parasitic inductance LS, a parasitic resistance RS and an additional resistance RA in series with the plates of the capacitor. The value of RA is chosen such that ##EQU1## The additional resistance RA in one embodiment is provided by a layer of conductive epoxy which is attached or added to one or both of the end plates of the capacitor. Electrical leads are coupled to the end plate having the epoxy by being embedded in the epoxy. If epoxy is not used on an end plate, the lead is coupled to the end plate in a conventional manner. In another embodiment the additional resistance RA is provided by a discrete resistor which is welded, soldered or otherwise attached to one or both of the end plates. If only one resistor is used, one lead of the capacitor is coupled to its end plate in a conventional manner and the second lead is coupled to the free end of the resistor. In one embodiment, the resistor is enclosed and the ends of the capacitor sealed by a non-electrically conductive epoxy. In another embodiment, the capacitor and resistor are enclosed within a container filled with non-conductive epoxy and the leads of the capacitor extend externally therefrom in a conventional manner so as to form an integrated capacitive element or device.

Filter & power compensation network - United States Patent 5,227,962

A filter network adapted to be placed in parallel with a power supply which provides a high impedance to the 60 Hz utility frequency but acts like a short circuit to all higher frequencies. The network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor. Signal levels above 60 Hz in a prototype circuit using seven such parallel circuits with a parallel capacitor coupled thereto shows that above 60 Hz the signal from the power supply is attenuated by 25-30 dB at 1 KHz and that the impedance is substantially resistive beyond 1 KHz. To maximize the power factor of the circuit comprising the network and consequently the dynamic range of audio equipment coupled thereto, the magnitude of the total capacitance of the network is chosen to be as close as possible to the magnitude of the input inductance of the audio equipment. Switches are provided for selectively adjusting the number of parallel circuits in the network to change its frequency response as well as to accommodate loads having different input inductive reactance at 60 Hz.

AC power line filter - United States Patent 5,260,862

A filter network adapted to be placed in parallel with a power supply which provides a high impedance to the 60 Hz utility frequency but acts like a short circuit to all higher frequencies. The network comprises a plurality of parallel circuits, each of which comprise a capacitor, an inductor and a resistor in series with a second resistor coupled in parallel with the inductor. Signal levels above 60 Hz in a prototype circuit using seven such parallel circuits with a parallel capacitor coupled thereto shows that above 60 Hz the signal from the power supply is attenuated by 25-30 dB at 1 KHz and that the impedance is substantially resistive beyond 1 KHz.

Digital interface cable - United States Patent 5,412,356

A single-ended digital interface cable and a balanced digital interface cable having a source end and a load end for propagating audio frequency signals in a digital format is disclosed. Each of the cables comprises a fixed capacitor or a capacitor and switch network which is coupled at or near the load end of the cables for providing a fixed bandwidth or for use in selectively controlling the bandwidth of the cables and a series resistance at each end thereof to dampen ringing.

Iconn® Universal Connector System - United States Patent 5,791,919

An electrical connector is set forth which is suitable for connection to a conductor which includes a connector member suitable for attachment, for example by soldering or by a crimping device, to a conductor, such as a cable. The electrical connector also includes a terminal pin connectable to an electrical receptor or terminal, for example in a part of an audio system. The connector member also includes a threaded part onto which any one of several types of alternative connector units may be mounted to enable use of the same conductor and its attached connector with different types of audio system receptors or terminals. A right-angle adapter may also be used to join the electrical connector to one of the alternative connector units.

Balanced power amplification system - United States Patent 5,914,636

A configuration of audio system components, utilizing standard amplifier components, wherein the audio system remains balanced through the speaker input terminals. For each channel of the system, a preamplifier produces a balanced output signal. Two power amplifiers or similar devices are conventionally configured to accept positive and negative input signals. The negative signal output of the preamplifier is connected to the positive input terminal of one of the power amplifiers, and the positive output signal of the preamplifier is connected to the positive input terminal of the other power amplifier. The negative and ground input terminals of both power amplifiers are connected to system ground. The connections between the preamplifiers and the amplifiers may be effected by a unique cable designed for this purpose. The positive output terminal of one of the power amplifier is connected to positive input terminal of the speaker, while the positive-output terminal of the other power amplifier is connected to the negative input terminal of the speaker. The negative output terminals of each power amplifier "floats", unconnected externally to the speakers.

Audio transmission line with Energy Storage Network (Input Terminator) - United States Patent 5,956,410

An audio signal transmission line including capacitive and/or inductive networks connected in series or parallel with an audio transmission cable providing for increased storage of electrical energy, and thereby overcoming energy storage problems associated with previous audio signal transmission systems which create unwanted pre-emphasis of audio signals at certain frequencies.

Audio signal cable with passive network - United States Patent 6,658,119

A network for altering the audio output of a system which comprises at least one series RC or RLC circuit coupled between the positive and ground conductor of a cable that is suitable for connecting an electrical musical instrument, or similar source, to an amplifier or other load. The components of the RC or RLC circuit are selected by determining the frequency at which the positive conductor's natural phase angle is 45°. Each of the RC or RLC circuits is selected to have a phase angle of -45° at a frequency equal to or different from the frequency at which the positive conductor has a phase angle of 45° depending upon the audio effect desired. In addition, the component values of the circuits are selected such that the measured impedance of the network at all frequencies in a predetermined frequency range is equal to or greater than 0.20 MO, and the overall combined capacitance of the cable and the capacitance and/or inductance of the network does not cause the effect of audible “roll-off” in the system.

Audio signal cable with passive network - United States Patent 7,242,780

A network for altering the audio output of a system which comprises at least one series RC or RLC circuit coupled between the positive and ground conductor of a cable that is suitable for connecting an electrical musical instrument, or similar source, to an amplifier or other load. The components of the RC or RLC circuit are selected by determining the frequency at which the positive conductor's natural phase angle is 45°. Each of the RC or RLC circuits is selected to have a phase angle of -45° at a frequency equal to or different from the frequency at which the positive conductor has a phase angle of 45° depending upon the audio effect desired. In addition, the component values of the circuits are selected such that the measured impedance of the network at all frequencies in a predetermined frequency range is equal to or greater than 0.20 MO, and the overall combined capacitance of the cable and the capacitance and/or inductance of the network does not cause the effect...

Electrical cable - United States Patent D314551

Electrical connector - United States Patent D317292

Elongated audio connector - United States Patent D434003

Enclosure for a consumer electronic device - United States Patent D436935

Enclosure for a speaker cable connector - United States Patent D446778

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