 Teletype compatible facsimile recorder |
| I claim: 1. A facsimile system for recording graphic signals comprising: a facsimile signal channel ... |
|
| Magnetic recording head assembly support with a sinuous gimbal spring |
| OF THE DRAWINGS Reference should now be had to the FIGS. 1 to 9 for a description of the preferred ... |
|
| Automatic reverse cassette type recorder |
| OF THE PREFERRED EMBODIMENT There will now be described by reference to the accompanying drawing ... |
|
| Continuously operating centrifuge drum for the sterilization of liquids |
| What is claimed is: 1. In a centrifuge suitable for purification of a liquid comprising a ... |
|
| Method of and apparatus for selectively controlling a plurality of remotely located loads |
| I claim: 1. A system for operating a plurality of variously remotely located loads from a single ... |
|
| Pneumatic temperature reset differential pressure controller |
| OF THE PREFERRED EMBODIMENTS A variable air volume control system constructed in accordance with ... |
|
| Television system for displaying and recording paths of motion |
| The primary object of the present invention is to improve the viewability of a television display ... |
|
| Video effects system with recirculation video combine and output combine |
| The video effects system according to the present invention provides a video system with enhanced ... |
|
| Data set diagnostic system |
| FIG. 1 depicts a communication system, or network, in which the present invention is used. A... |
|
| Echo suppression circuit |
| What is claimed is: 1. An echo suppression circuit comprising an adder having an input means for ... |
|
|
Loudspeaker having a two-part diaphragm for use as a car loudspeaker
| Details |
Inventors: Nieuwendijk, Joris A. M.; Bax, Johannes W. T.; Kamphues, Johannes J. M.; de Haas, Franciscus C. M.;
Assignee: U.S. Philips Corp. (New York, NY)
Primary Examiner: Hix; L. T.
Assistant Examiner: Brown; Brian W.
Attorney, Agent or Firm: Franzblau; Bernard
An electrodynamic loudspeaker (1) has a diaphragm comprising a central part (2) and a peripheral part (3), and a voice-coil device (9, 10) coupled to the central part (2). The surface ratio S.sub.2 /S.sub.1 complies with the relationship 0.5.ltoreq.S.sub.2 /S.sub.1 .ltoreq.6, where S.sub.1 and S.sub.2 are the surface areas of the central part (2) and the peripheral part (3) respectively. The mass ratio m.sub.2 /m.sub.1 complies with the relationship 0.5.ltoreq.m.sub.2 /m.sub.1 .ltoreq.8 where m.sub.1 and m.sub.2 are the mass of the central part (2) and the voice-coil device (9, 10) and the mass of the peripheral part (3) respectively. Further, the stiffness imposed on the diaphragm by the space (6, 6') defined by the diaphragm (2, 3) and the chassis (4) and/or the magnet system (7) is smaller than the stiffness of the diaphragm itself. Thus it is possible to derive a car loudspeaker which has a specific dip in its frequency response characteristic P (FIG. 2a), measured in an anechoic room. |
|
DETAILED DESCRIPTION In order to obtain a frequency response characteristic with a broadened dip, the loudspeaker in accordance with the invention should be characterized in that the first value and the second value are equal to 0.
5 and 6 respectively, the third value and the fourth value are equal to 0.
5 and 8 respectively, and in that the stiffness imposed on the diaphragm by the space formed by the diaphragm and the magnet system and/or the chassis is smaller than the stifness of the diaphragm.
In fact, the requirement that the stifness imposed on the diaphragm by the space formed by the diaphragm and the magnet system and/or the chassis be smaller than the stiffness of the diaphragm itself, means that the motion of the diaphragm should not be impeded by the air volume at the rear of the diaphragm.
In other words: the air volume at the rear diaphragm should not or not significantly affect the frequency response characteristic of the loudspeaker.
The stiffness of the diaphragm is defined as the force [in N], exerted on the voice-coil former in the direction of its excursion divided by the excursion of the voice-coil former [in m].
The above requirement can be met by making the air volume behind the diaphragm large enough, provided that it is a fully enclosed volume.
However, this renders the loudspeaker rather bulky, which may be a disadvantage when it is to be used as a car loudspeaker.
Another possibility is to provide the magnet system and/or the chassis with at least one aperture in order to provide an acoustic path through the magnet system and/or the chassis of the transducer.
The invention is based on the recognition of the fact that during use of a loudspeaker having a two-part diaphragm, when the mechanical damping of the peripheral part is chosen correctly, the frequency response versus input impedance characteristic of the loudspeaker substantially exhibits only two maxima which correspond to the two resonant frequencies f.
sub.
1 and f.
sub.
2 for which the central part and the peripheral part vibrate in phase and in phase opposition relative to each other
|
| Related patents |
|
|
Horizontal synchronizing system
In accordance with an embodiment of the present invention, a phase control circuit for the horizontal frequency synchronizing pulse generator in a television camera ...
|
|
|
Multiple scanning type television receiver
The above problem is overcome by the present invention which is intended for use in combination with a horizontal deflection circuit of a multiple scanning type ...
|
|
|
Selective efficiency videofrequency non-linearity correction device
The invention provides a selective efficiency video frequency nonlinearity correction device, for the precorrection of nonlinearity introduced into the video frequency ...
|
|
|
Compression of data on status of remote equipment
The environment of this invention is a communication system in which each of a number of ground stations connected by a remote relay, in general satellite-borne, has a ...
|
|
|
Digital-analog converter
In accordance with the present invention, there is provided a novel digital-analog converter wherein a digital signal from an analog-digital converter is compared with a ...
|
|
|
Digital equalizer for data-transmission system
We claim: 1. An equalizer for digital messages insertable between a transmission channel and a load, comprising: a data lead for incoming pulses; a cascade of several ...
|
|
|
A/D and D/A converter using C-2C ladder network
It is therefore an object of the present invention to provide A/D and D/A converters employing a capacitor ladder network which may be manufactured using monolithic, ...
|
|
|
Switching device for detecting interruptions in transmission lines
The object of the present invention is to provide a device for switching the transmission lines, wherein, by the logical exclusive OR from a set of digital signals ...
|
|
|
Method and device for controlling radiation
OF THE INVENTION Referring now to FIGS. 1 through 4, which describe an embodiment of the device of this invention. The lens device comprises a first transparent plate 1 ...
|
|
|
Automatic dialer with a programmable pause
Against the foregoing background, a general aim of the present invention is to provide methods and means for utilizing raster input scanners as readers for automatic ...
|
|
|
Image Analysis 
