Marantz HD77

Last updated
Box the speakers were packaged in; showing foam grille Marantz HD77 speaker box cardboard package.JPG
Box the speakers were packaged in; showing foam grille

HD77 is a model name of Marantz 4-way high-fidelity loudspeakers which were produced during the mid-1970s. They were bass reflex speakers, but came with a cylindrical piece of foam which fit into the bass-reflex port of the enclosure if the listener preferred the more accurate bass response provided by airtight speaker boxes. However, they were not fully airtight this way, but rather what is known as aperiodic. They were designed by former JBL Engineer Edmond May. The foam plug in port was in fact a "closed-cell" type which did in fact seal the cabinet completely. How it worked was it was cut slightly larger than opening and when inserted, you turned the retainer screw and it would tighten and compress the plug, thereby sealing the cabinet to make the loudspeaker a "suspension" type. The controls on baffle are resistive potentiometers, which changed the response curve of corresponding driver from soft to bright, giving great versatility to adapt within almost any listening environment.

Contents

HD77 before repair Marantz hd77 .jpg
HD77 before repair

Technical details

Weight: 49 lb (21 kg)

Power handling: 250 watts RMS, 330 Watts peak

Impedance: 8 ohms

Physical dimensions

Marantz HD77s had a total volume of 2.8 cubic feet (79 L) each. The cabinet dimensions are:

Depth: 12 inches

Width: 15 inches

Height: 28.5 inches


Drivers

The four drivers of the Marantz HD77s are a woofer, mid-range, tweeter and super tweeter. The given frequency responses are what the crossover circuit feed to each speaker, not what each speaker would respond to with no crossover circuit(full spectrum). The mid-range, tweeter and super tweeter have crossover controls for switching between a laboratory "flat" +/- 0db neutral response and a "room EQ" response. Tested frequency response is measured in an anechoic chamber from 20 Hz to 20 kHz, and displayed in a graph shown in original Marantz brochure. Crossover and frequency response are two different things. Crossover points are established for each driver and their specified frequency range. Without crossover points, the drivers would distort and likely overheat and burn out due to the production of the full spectrum of frequencies, with exception of the woofer which inherently struggles with producing higher frequencies. The drivers together create a complete spectrum frequency response.

Woofer

The woofer is 12 inches (30 cm) in diameter with a frequency response of 30 to 500 hertz.

Mid-range

The mid-range is 4.5 inches in diameter with a frequency response of 500 hertz to 3 kilohertz.

Tweeter

The tweeter is a 2-inch (5.1 cm) LPF film dome-type. The tweeter's frequency response is from 3 kHz to 8 kHz.

Super tweeter

The super tweeter is a 1-inch LPF film dome with response from 8 to 23 kHz, which extends 3 kHz above the nominal range of audio frequencies which can be heard by the human ear.

Related Research Articles

<span class="mw-page-title-main">Subwoofer</span> Loudspeaker for low-pitched audio frequencies

A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies, known as bass and sub-bass, that are lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range that is covered by 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 octaves 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.

<span class="mw-page-title-main">Loudspeaker</span> Converts an electrical audio signal into a corresponding sound

A loudspeaker is a combination of one or more speaker drivers, an enclosure, and electrical connections. The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound.

<span class="mw-page-title-main">Audio crossover</span> Electronic filter circuitry used in loudspeakers

Audio crossovers are a type of electronic filter circuitry that splits an audio signal into two or more frequency ranges, so that the signals can be sent to loudspeaker drivers that are designed to operate within different frequency ranges. The crossover filters can be either active or passive. They are often described as two-way or three-way, which indicate, respectively, that the crossover splits a given signal into two frequency ranges or three frequency ranges. Crossovers are used in loudspeaker cabinets, power amplifiers in consumer electronics and pro audio and musical instrument amplifier products. For the latter two markets, crossovers are used in bass amplifiers, keyboard amplifiers, bass and keyboard speaker enclosures and sound reinforcement system equipment.

<span class="mw-page-title-main">Tweeter</span> Type of loudspeaker

A tweeter or treble speaker is a special type of loudspeaker that is designed to produce high audio frequencies, typically up to 100 kHz. The name is derived from the high pitched sounds made by some birds (tweets), especially in contrast to the low woofs made by many dogs, after which low-frequency drivers are named (woofers).

<span class="mw-page-title-main">Mid-range speaker</span> Loudspeaker driver

A mid-range speaker is a loudspeaker driver that reproduces sound in the frequency range from 250 to 2000 Hz.

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 a few hundred Hz. The name is from the onomatopoeic English word for a dog's deep 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.

<span class="mw-page-title-main">Full-range speaker</span> Type of loudspeaker

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.

<span class="mw-page-title-main">Loudspeaker enclosure</span> Acoustical component

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.

<span class="mw-page-title-main">Bi-amping and tri-amping</span> Practice of using two or three audio amplifiers to amplify different audio frequency ranges

Bi-amping and tri-amping is the practice of using two or three audio amplifiers respectively to amplify different audio frequency ranges, with the amplified signals being routed to different speaker drivers, such as woofers, subwoofers and tweeters. With bi-amping and tri-amping, an audio crossover is used to divide a sound signal into different frequency ranges, each of which is then separately amplified and routed to separate speaker drivers. In Powered speakers using bi-amping, multiple speaker drivers are in the same speaker enclosure. In some bi-amp set-ups, the drivers are in separate speaker enclosures, such as with home stereos that contain two speakers and a separate subwoofer.

<span class="mw-page-title-main">Guitar speaker</span>

A guitar speaker is a loudspeaker – specifically the driver (transducer) part – designed for use in a combination guitar amplifier of an electric guitar, or for use in a guitar speaker cabinet. Typically these drivers produce only the frequency range relevant to electric guitars, which is similar to a regular woofer type driver, which is approximately 75 Hz — 5 kHz, or for electric bass speakers, down to 41 Hz  for regular four-string basses or down to about 30 Hz for five-string instruments.

The Air Motion Transformer (AMT) is a type of electroacoustic transducer. Invented by Oskar Heil (1908–1994), it operates on a different transduction principle from other loudspeaker designs, such as moving coil, planar magnetic or electrostatically-driven loudspeakers, and should not be confused with planar or true ribbon loudspeakers. In contrast to a planar ribbon loudspeaker, the diaphragm of the AMT is of pleated shape similar to a bellows. The AMT moves air laterally in a perpendicular motion using a metal-etched folded sheet made of polyethylene terephthalate (PET) film. The circuit path embossed on the PET membrane, acts as the voice coil unit. The diaphragm is then housed between 4 stacks of steel pole-plate pieces positioned at 45° within a high-intensity, quadratic, opposing magnetic field. The air motion transformer with its sheet film equally exposed at 180° behaves as a dipole speaker, exciting front and rear sonic waves simultaneously.

<span class="mw-page-title-main">Acoustic suspension</span> Loudspeaker cabinet design

Acoustic suspension is a loudspeaker cabinet design that uses one or more loudspeaker drivers mounted in a sealed box. Acoustic suspension systems reduce bass distortion which can be caused by stiff suspensions required on drivers used for open cabinet designs.

<span class="mw-page-title-main">NS-2000</span>

First produced in 1982, the Yamaha NS-2000 is an improved version of the older NS-1000 speaker that was first made in the early to mid-1970s. Like the NS-1000, it is a 3-way acoustic suspension speaker system with a beryllium-dome midrange and tweeter. However, the woofer of the NS-2000 was entirely new, made of pure carbon fiber instead of paper. The cabinet is also improved and is larger and heavier than that of the NS-1000.

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.

Loudspeaker time-alignment, usually simply referred to as "time-alignment" or "Time-Align", is a term applied in loudspeaker systems which use multiple drivers to cover a wide audio range. It involves delaying the sound emanating from one or more drivers to correct the transient response, improve accuracy and, in non-coaxial drivers, improve the directivity or lobe tilting at the crossover frequencies. It employs adjusting the front-to back spacing of the individual drivers so that the sound output is truly simultaneous.

The Wharfedale MACH series of loudspeakers consists of the MACH 3, 5, 7, and 9. This is an informational page devoted to owners and users of these loudspeakers and those interested in history and construction of electronic sound reproduction.

<span class="mw-page-title-main">Veritone Minimum Phase Speakers</span> Defunct speaker manufacturing company

Veritone Minimum Phase Speakers, or VMPS, was a loudspeaker manufacturer founded in 1977 by speaker designer Brian Cheney. Many VMPS speakers received favorable reviews from audio critics, such as the RM40, which was awarded Best of CES in the High-End Audio category in 2002. VMPS was in operation for over 35 years, from January 1977 to December 2012, when it closed soon after the death of company owner Brian Cheney on December 7, 2012.

<span class="mw-page-title-main">Keyboard amplifier</span>

A keyboard amplifier is a powered electronic amplifier and loudspeaker in a speaker cabinet used for the amplification of electronic keyboard instruments. Keyboard amplifiers are distinct from other types of amplification systems such as guitar amplifiers due to the particular challenges associated with making keyboards sound louder on stage; namely, to provide solid low-frequency sound reproduction for the deep basslines that keyboards can play and crisp high-frequency sound for the high-register notes. Another difference between keyboard amplifiers and guitar/bass amplifiers is that keyboard amps are usually designed with a relatively flat frequency response and low distortion. In contrast, many guitar and bass amp designers purposely make their amplifiers modify the frequency response, typically to "roll-off" very high frequencies, and most rock and blues guitar amps, and since the 1980s and 1990s, even many bass amps are designed to add distortion or overdrive to the instrument tone.

<span class="mw-page-title-main">Linn Isobarik</span> Loudspeaker designed and manufactured by Linn Products

The Linn Isobarik, nicknamed "Bariks" or "Briks", is a loudspeaker designed and manufactured by Linn Products. The Isobarik is known for both its reproduction of low bass frequencies and being very demanding on amplifiers.

<span class="mw-page-title-main">Yamaha NS-10</span> Model of Yamaha studio reference loudspeakers

The Yamaha NS-10 is a loudspeaker that became a standard nearfield studio monitor in the music industry among rock and pop recording engineers. Launched in 1978, the NS-10 started life as a bookshelf speaker destined for the domestic environment. It was poorly received but eventually became a valuable tool with which to mix rock recordings. The speaker has a characteristic white-coloured mid–bass drive unit.

References