DE102005035604A1 - Loudspeaker e.g. dynamic loudspeaker, for e.g. public-address system, in e.g. airport, has coil arranged in magnetic field such that voltage evaluatable as test signal is inducible in coil with movement of frequency response system - Google Patents

Abstract

The loudspeaker has a coil (16) that is coupled to a mechanical frequency response system in such a manner that the system is movable in vibration based on a changing electrical excitation signal that is adjacent to the coil. Another coil (18) or conductor loop is movably coupled with a part of the system and is arranged in a magnetic field in such a manner that a voltage evaluatable as test signal is inducible in the coil (18) with a movement of the system. An independent claim is also included for a method for function control of a loudspeaker.

Description

technical area

The The invention relates to a loudspeaker according to the preamble of the claim 1 and a method for function control thereof according to the preamble of claim 7.

speaker are electroacoustic transducers, which convert electrical energy into acoustic Energy, so in sound, convert. This conversion can with different Transducer principles done. How to distinguish between dynamic, electrostatic, piezoelectric and magnetic speakers.

at the dynamic loudspeaker makes you feel the effect of the Lorenz force exploiting which a current-carrying conductor in a permanent magnetic field experiences. When arranging a coil in a magnetic field and to a mechanical vibration system, in particular to a membrane, coupled, the membrane is a function of flowing through the coil Excited current vibrated, causing the adjacent Air condenses and relaxes. Through this mechanism are sound waves generated, which spread in the vicinity of the speaker.

By disorders When converting from electrical to acoustic energy, the How a speaker or speaker system works be affected. In particular, it is possible that damaged the diaphragm or is trapped. It is desirable such an impairment the ability to vibrate the membrane as possible to identify quickly. In many cases the simple use of human hearing is sufficient for functional diagnosis. The functional diagnosis becomes problematic in the case of long-range design Sound systems, such as in large buildings, in airports or like. The discovery of loudspeaker failures is particular hard to reach Not always possible.

Also in vehicles of the upper price range, the operational readiness must closely monitored by public address systems can be. A vehicle occupant can easily experience the malfunction of subsonic or midrange notice, but not that of tweeters, as the radiated power of the Woofer and midrange that of the tweeter usually far exceeds. The certainty about that a particular speaker actually works is here very important as it is unacceptable for a customer is when the sound deteriorates due to speaker failure becomes.

State of technology

Out Functional controls are known in the prior art, in which the emission of sound is detected by microphone systems, which are arranged in front of the loudspeaker diaphragm. Disadvantageous Such devices is that for diagnosis separate components with separate power supply needed. Besides that is their feedback often with certain imponderables connected, especially in a strong noise in the immediate Near the Speaker.

Presentation of the invention, Task, solution, advantages

It The object of the present invention is to provide a loudspeaker in which a functional diagnosis by simple means is feasible and become a reliable one feedback of the system leads.

These The object is achieved by means of a Loudspeaker with the features mentioned in claim 1 or by means a method having the features mentioned in claim 7.

Thereby, that at least one second coil, conductor loop or the like Motion coupled with at least a portion of the mechanical vibration system and in the magnetic field is arranged such that during a movement of the mechanical vibration system evaluable as a test signal Stress in her is inducible, is a simple, on the microphone principle based diagnosis possible. Furthermore is advantageous that the speaker together with the diagnostic element as a compact component is present.

In A preferred embodiment of the invention provides that the speaker is an electrodynamic speaker with a permanent magnet with a pole core and with a voice coil carrier comprising the pole core, wherein the windings of the first and second coils are disposed on the voice coil bobbin are. Such an arrangement results from slight modifications common electrodynamic loudspeaker of the prior art.

For the transmission of the test signal, multiple configurations are possible. At the simplest Configuration is provided that the excitation signal and the test signal on separate power supply lines of the speaker become. For this purpose, a speaker must have three or four ports.

alternative Is it possible, that the excitation signal and the test signal on the same power supplies of the speaker become. This has the advantage that no additional strands are provided on the speaker body must be, but here is the evaluation of the test signal in general not without additional Signal modulation feasible. Such a modulation may be, for example, that a sinusoidal Signal using a Schmitt trigger and a flip-flop is converted into a test signal, which is essentially a Rectangular voltage corresponds. To prevent a sound excitation signal for the Membrane in the audible Area is created, the procedure is the functional check of the Speaker using an excitation signal with a sufficiently high frequency, for example 40 kHz, executed.

Further preferred embodiments of the invention will become apparent from the others, in the subclaims mentioned features.

Short description the drawings

below the invention is in an embodiment with the attached Drawings closer explained. In schematic representations:

1 a section through a loudspeaker according to the invention;

2 a switching arrangement with modulation of the test signal and

3 a switching arrangement with digital transmission of the test signal.

best way for execution the invention

In a total in the 1 to 3 With 100 designated speaker forms in which by a permanent magnet 10 a yoke 12 and a pole plate 14 formed magnetic system from an air gap, in which a voice coil bobbin 32 is suspended. On the voice coil bobbin 32 are an excitation coil 16 and a test coil according to the invention 18 arranged. One to the voice coil bobbin 32 coupled membrane 24 , which together with a centering membrane 20 and a dust cover designed as a dome 22 forms a mechanical vibration system, transmits vibrations of the oscillating coil carrier 32 into the air and converts them into audible sound waves. On a loudspeaker basket 28 , which takes over the task, the voice coil bobbin 32 and the magnet system 10 take up, are Zuführungslitzen 26 . 30 arranged, which as connections for the exciting coil 16 and the test coil 18 serve. The exciter coil 16 gets through the feedlines 30 supplied with an excitation current. Through the flow of current an alternating magnetic field is built up, which moves the membrane forward and backward. In this way, current vibrations are converted into air vibrations and emitted as sound waves. When the membrane 24 moved freely, is a evaluable as a test signal voltage in the test coil 18 which, given a suitable potential reference, acts as a test signal on the feed strand 26 is applied. If the membrane vibration is impaired, no test signal is measured or the test signal is at a lower level than with a functional membrane. By evaluation of the test signal on the feed strand 26 Thus, a simple diagnosis of the speaker function is possible.

2 shows a switching arrangement in which the on the test coil 18 tapped test signal by a modulator 34 (eg in a range around 100 kHz) modulated and on the two-wire feed line 36 of the speaker 100 is placed. The resulting in a functional membrane movement high-frequency signal can thus be easily evaluated. A the speaker 100 upstream bandpass filter 38 , which transmits a frequency range from 0 to 30 kHz and from a power amplifier 40 (12V / 240V), prevents the transmission of the high-frequency signal to the exciter coil 16 and thus also the generation of unwanted movements of the speaker diaphragm 24 ,

3 shows a switching arrangement in which the on the test coil 18 tapped test signal via a WLAN Bluetooth module 42 is transmitted digitally with an upstream A / D converter to a collecting station, not shown. Alternatively, not the test signal itself is transmitted, but information derived therefrom, which merely provides information about the function and the identifier of the loudspeaker. For example, this signal includes only a single bit indicating the proper functioning of the loudspeaker, as well as a name or location of the loudspeaker. On pure feedback of the test signal on the supply line 36 of the speaker 100 can be omitted in this embodiment.

Claims (10)

Speaker ( 100 ) with at least one device for generating a magnetic field ( 10 ) and at least one first coil ( 16 ), which in the magnetic field ( 10 ) and to a mechanical vibration system, in particular to a membrane ( 24 ) is coupled such that the mechanical vibration system as a function of a changing, on the first coil ( 16 ) is set into oscillatory electrical excitation signal, characterized in that at least one second coil ( 18 ), Conductor loop or the like with at least a part of the mechanical vibration system and coupled in the magnetic field ( 10 ) is arranged such that when a movement of the mechanical vibration system evaluable as a test signal voltage is inducible in it. Loudspeaker according to claim 1, characterized in that the loudspeaker ( 100 ) an electrodynamic loudspeaker with a permanent magnet ( 10 ) with a pole core and a voice coil carrier comprising the pole core ( 32 ), wherein the windings of the first and the second coil ( 16 . 18 ) on the voice coil former ( 32 ) are arranged. Loudspeaker according to one of the preceding claims, characterized in that the loudspeaker ( 100 ) an active speaker with an amplifier ( 40 ) for feeding the first coil ( 16 ). Loudspeaker according to one of the preceding claims, characterized in that the excitation signal and the test signal are applied to the same power supply lines of the loudspeaker ( 100 ) are transferable. Loudspeaker according to one of claims 1 to 3, characterized in that the excitation signal and the test signal on separate power supply lines of the loudspeaker ( 100 ) are transferable. Loudspeaker according to one of the preceding claims, characterized in that the test signal is generated by a modulator ( 34 ) is modulated. Method for checking the function of a loudspeaker ( 100 ), where the speaker ( 100 ) at least one device for generating a magnetic field ( 10 ) and at least one first coil ( 16 ) arranged in the magnetic field and to a mechanical vibration system, in particular to a membrane ( 24 ) is coupled in such a way that the mechanical vibration system in response to a changing, on the first coil ( 16 ) is applied to vibrate, characterized in that a test signal is evaluated, which results from the fact that during the movement of the mechanical vibration system, a voltage in at least one second coil ( 10 ), Conductor loop or the like ( 18 ), the second coil ( 18 ), Conductor loop or the like with at least a part of the mechanical vibration system is motion-coupled and arranged in the magnetic field. Method according to claim 7, characterized in that that the test signal is modulated. Method according to one of claims 7 to 8, characterized that the functional check is carried out in a test phase. Method according to one of claims 7 to 9, characterized that at least one inaudible Frequency component is evaluated in the test signal.