Marantz HD77
Encyclopedia
Marantz
Marantz is a company that develops and sells upper-mid range to high-end audio products.The first Marantz audio product was designed and built by Saul B. Marantz in his home in Kew Gardens, New York...
4-way high-fidelity loudspeakers which were produced during the mid-1970s. They were bass reflex
Bass reflex
A Bass reflex system is a type of loudspeaker enclosure that uses the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical closed box loudspeaker or an infinite baffle mounting.A reflex port is the distinctive feature of a...
speakers, but came with a cylindrical
Cylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...
piece of foam
Foam
-Definition:A foam is a substance that is formed by trapping gas in a liquid or solid in a divided form, i.e. by forming gas regions inside liquid regions, leading to different kinds of dispersed media...
which fit into the bass-reflex port
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
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. Let me enlighten you a bit about these speakers: 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 cabinet completely. How it worked was it was cut slightly larger than opening and when inserted, you turn 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.
Technical details
Weight: 49 lb (21 kg)Power handling: 250 watts RMS
Root mean square
In mathematics, the root mean square , also known as the quadratic mean, is a statistical measure of the magnitude of a varying quantity. It is especially useful when variates are positive and negative, e.g., sinusoids...
, 330 Watts peak
Impedance: 8 ohms
Physical dimensions
Marantz HD77s had a total volumeVolume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
of 2.8 cubic feet (79.3 l) each. The cabinet
Cabinet (furniture)
A cabinet is usually a box-shaped piece of furniture with doors or drawers for storing miscellaneous items. Some cabinets stand alone while others are built into a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood or, now increasingly, of synthetic...
dimensions
Dimensions
Dimensions is a French project that makes educational movies about mathematics, focusing on spatial geometry. It uses POV-Ray to render some of the animations, and the films are release under a Creative Commons licence....
are:
Depth: 12 inches
Width: 15 inches
Height: 28.5 inches
Drivers
The four driversLoudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
of the Marantz HD77s are a woofer
Woofer
Woofer is the term commonly used for a loudspeaker driver designed to produce low frequency sounds, typically from around 40 hertz up to about a kilohertz or higher. The name is from the onomatopoeic English word for a dog's bark, "woof"...
, mid-range, tweeter
Tweeter
A tweeter is a loudspeaker designed to produce high audio frequencies, typically from around 2,000 Hz to 20,000 Hz . Some tweeters can manage response up to 65 kHz...
and super tweeter
Super Tweeter
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...
. The given frequency response
Frequency response
Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system. It is a measure of magnitude and phase of the output as a function of frequency, in comparison to the input...
s are what the crossover circuit fed to each speaker, not what each speaker would respond to with no crossover circuit. The mid-range, tweeter and super tweeter have controls for switching between a laboratory flat and neutral response and a room EQ response. Frequency Response is measured in an Anechoic Chamber from 20Hz to 20kHz, 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 within it's specified frequency range. Without crossover points, the drivers would simply overheat and burn out, With exception of the woofer. The drivers perform together to create a frequency response.
Woofer
The woofer is 12 inches in diameterDiameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
with a frequency response of 30 to 500 hertz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
.