FR2632801A1 - Adapter for curvilinear acoustics - Google Patents

Abstract

Device for reproduction of acoustic waves ranging from infrasound to harmonics below 1000 Hertz. The invention relates to a device making it possible to render circular the paths of the infrasound waves so that they are no longer, or are only slightly, subjected to the standing-wave conditions in the location to be rigged for sound. It consists of two sealed containers labelled 1 interacting in electrical phase on a resonator volume 2 which shapes the acoustic fundamentals which radiate through three vertical orifices FA. The device according to the invention is particularly intended for any system for electroacoustic reproduction.

Description

- DESCRIPTION
A / GENERAL
The adapter for curvilinear acoustics is an electroacoustic apparatus, which starting from a simple electronics, will allow any owner of said system to adapt to acoustic curvilism its conventional stereophonic equipment.

 Unlike the system previously filed under the patent application number, referenced under the number 87 11241; it is directly industrializable, at an interesting price for the general public.

 Before describing this adapter, we must define what is meant by CURVILIGNE. Acoustic curvilism arises from a discovery made by the author of this patent application. The brief of the work has been tabled.

 To summarize the thesis, the author proved that particle waves move at constant velocities on quasicircular trajectories called TROCHOIDALES.

The simplest and best known in ACOUSTICS-is the CARDIOID.

Curvilism is latent in nature; it will be the consequence of a resonance.

 In so-called stereophonic electroacoustics; setting.

resonance is not linear in frequency. All existing loudspeakers have low cutoff frequency 80 Hertz. This cut is explained by the piston operation of the speaker diaphragm.

It has been proved that for the very low electric frequencies, the air molecules are expelled in the axis of displacement of the piston; the acoustic field thus created is
PROJECTIVE, it results
a stationary wave field,
- a very bad sound propagation because the
Air molecules oscillate around a resting point.

 The adapter for curvilinear acoustics will have the effect of making EQUIPROJECTIVE the entire band of acoustic frequencies to be reproduced, that is to say, to ensure that the acceleration of the particle is orthogonal to the displacement of the latter at low frequencies. On the other hand this adapter will have the effect of reducing the standing wave rate by transforming the acoustic field. This one becomes circular, the local sonorized becomes a resonant medium.

Bz DESCRIPTION OF THE EQUIPMENT
1 ") Speaker acoustic CURVILIGNE: (board 2/2)
This speaker is experienced since December 1985. It is such that two low-frequency speakers project air molecules towards each other.

To do this it is necessary that the two loudspeakers are coplanar on the one hand, and their membranes vis a vis on the other hand.

 Electrically both speakers are in electrical phase. These are mounted in two sealed hermetic forms, marked i on the 2X2 board. Unlike conventional speakers, rear volume is not critical.

 The volume m is such that, on three vertical faces, it lets the sound flow pass, mark FA on the board. The distance between each cone of the loudspeakers is equal to the diameter of these.

 The volume z receives the adaptation electronics.

2 ") Electronipue of adaptation: (plate 1/2)
This is largely contained in Plate 1, 2. It involves
passive filtering at high power (maximum
100 Watts),
a mixer from which a monophonic signal originates
bandwidth (0 Hertz, 256 Hertz.

- an electromechanical switch that protects
the electronics when the adapter is out
voltage,
an amplifier 130 Watts under 8 Ohms,
- a mains supply delivering 10 amperes under
55 Volts.

a> Amplifier
The mount is a classic PUSH PULL bandwidth 5 Hertz at 20 Kilohertz. He was chosen to
- its low distortion 1 eco modulation peaks,
its very good signal-to-noise ratio 100 dB mo,
- its cost 400 French francs.

 It is preceded by a 40-dBb filter per decade.

Frequencies above 1000 Hertz are greatly attenuated. In this way the attenuation of the signals at the cut-off frequency of the low-frequency loudspeakers will reach 50 dbmo.

b> Electromechanical switch:
This arrangement is necessary because the stereo amplifier can at any time output electrical power to the adapter which is connected to the interface.

 The voltage divider bridges are such that the signal-to-noise ratio is at each maximum instant.

Thus the voltage applied to the operational amplifiers can be of the order of +5.6 volts for 45 volts at power peaks.

 In the absence of the reference-R relay, these voltages could be applied while the adapter is de-energized. This would result in an alteration of the operational amplifiers ...

The electromechanical switch comprises a control circuit which allows the bonding of the relay R if and only if the difference in low voltage potentials (at the level of the arrows> exceeds 24 volts,
During a few seconds a voltage of 24 Volts is applied to the relay R. The time results from an integration constant. there is sticking of the relay.

Subsequently, the relay R is maintained by the voltage
ALP through an additional resistor that drops the relay holding voltage to 12 Volts.

c> Signal mixer
The reference signals present on the wires
- EG left entry,
- ED right entry, are weakened by dividing bridges of 1/8 ratio voltages.

The signals applied to the speakers on the wires
- SG left exit,
- SD output right, are reversed and added. The voltage ratio in principle 118 can be adjusted by a potentiometer. This setting will compensate for relative errors due to mounting.

 Subsequently, the four signals EG, ED, SG, SD are added, so that the signal AMP is the vector complement of the sum of the signals SG + SD.

d> Passive filtering
It is bistandard, the double switch inverter AI allows adaptation of impedance 4 or 8 Ohms. The outputs to the enclosure are performed in parallel on a self-shock of 10 milihenrys.

 The AI adapter parallels a capacity of 82 F on the fixed capacity of 68 F. The capacities are in polypropilene technology of voltage 160 Volts.

The performance of the filter is reproduced in the following tables:

<tb><SEP> Impedance <SEP> 4 <SEP> Ohms
<tb> f (hertz) <SEP> || VS || <SEP> | VS <SEP> || <SEP> Zi || <SEP> | Zi
<tb><SEP> 8 <SEP> 0.004 <SEP> 173 <SEP> 134 <SEP> -90
<tb><SEP> 16 <SEP> 0.015 <SEP> 166 <SEP> 67.8 <SEP> -90
<tb><SEP> 32 <SEP> 0.057152 <SEP> 32.84 <SEP><SEP> -88
<tb><SEP> 64 <SEP> 0, <SEP> 192 <SEP> 127 <SEP><SEP> 14.82 <SEP> -82 <SEP>
<tb><SEP> 128 <SEQ> 0.482 <SEP> 90 <SEP> 7.44 <SEP> -60
<tb><SEP> 256 <SEP> 0.813 <SEP> 54 <SEP> 1 <SEP><SEP> 4.78 <SEP> -40
<tb><SEP> 512 <SE> O, <SEP> 939 <SEP><SEP> 29 <SEP> 4.23 <SEP> -22
<tb><SEP> 1024 <SEP> 1 <SEP> 0.983 <SEP> 14 <SEP> 4.06 <SEP> -10
<tb><SEP> 2048 <SEP><SEP> 0.996 <SEP> 7 <SEP> 4.01 <SEP> -5 <SEP>
<Tb>

<tb><SEP> 4096 <SEP> 0.999 <SEP> 4 <SEP> 4.00 <SEP> -l <SEP>
<tb><SEP> 8192 <SEP> 1 <SEP> 2 <SEP> X <SEP> 4.00
<tb><SEP> Impedance <SEP> 8 <SEP> ohms
<tb> f (hertz) <SEP><SEP> l || VS || <SEP> | VS <SEP> || Zi || <SEP> | Zi
<tb><SEP> 8 <SEP> 0.002 <SEP> 176 <SEP> 266 <SEP> -90
<tb><SEP> 16 <SEP> 0.007 <SEP> 173 <SEP> 160 <SEP> -90
<tb><SEP> 32 <SEP> 0.026 <SEP> 1 <SEP> -1.66 <SEP> 73.1 <SEP> -90
<tb><SEP> 64 <SEP> 0.107 <SEP> 1 <SEP><SEP> 150 <SEP> 32.72 <SEP> -86
<tb><SEP> 128- <SEP> 0.38. <SEP> 119 <SEP> * <SEP> 14.87 <SEP> -74. <September>
<tb><SEP> 256 <SEP> 0.81 <SEP> 69 <SEP> 8.73 <SEP> -42
<tb><SEP> 512 <SEP> 0.97 <SEP> 33 <SEP> 8.08 <SEP> -19
<tb><SEP> 1024 <SEP> 0.99 <SEP> 17 <SEP> 8.02 <SEP> -10
<tb><SEP> 2048 <SEP> 0.998 <SEP> 8 <SEP> 8.00 <SEP> -4
<tb><SEP> 4096 <SEP> 0.999 <SEP> - <SEP> 4 <SEP> 8.00 <SEP> -2
<tb><SEP> i <SEP> I <SEP>
<tb><SEP> 8192 <SEP> 1 <SEP> 1 <SEP> 2 <SEP> W <SEP> 8.00 <SEP> -1
<Tb>

 The signals present. on the outputs SG and SD correspond to the desired evolution. The impedance seen by the amplifier drops steadily and stabilizes around 512 Hertz.

However, for the AMP component, it is too strong. At 1024 Hertz; there remains a signal of the order of 30% of the incident signal. This one would require a reproduction in the acute midrange register. This is not desirable at the adapter. The 1000 Hertz filter will bring the attenuation to 13 dbmo at 1024 Hertz and 50 dbmo at 4096 Hertz. In this way the low frequency speakers will be sufficient for the proper functioning of the adapter
We know that the ear is insensitive to phase error, so we will accept such a distortion.

The error will be less than 20 angle over the 4 octaves covering the bandwidth, ranging from 256 Hertz to 4096 Hertz.

 In amplitude, the vector error is infinitessinal because always less than 1.7%.

C / CONCLUSIONS
The interest of the curvilinear adapter is obvious. A study of the frequency spectra produced by various modulating sources showed that all these sources have a same fundamental frequency 16 Hertz, as well
- a LA 3 sung has for fundamental an equal level
at +5 DBa at 16 Hertz,
- At the extreme a percussion of cymbals to fon
damental a noise level equal to -15 dBa at 16 Hertz.

Existing loudspeakers are in fact extended band pass filters (50 Hertz to 16 Kilohertz)
The attenuation of the filter varies according to the architecture chosen for the enclosure.

 HIFI sound (high fidelity) is a sound that ignores the fundamental 16 Hertz.

 Subsequently the local causes a new acoustic distortion. The said room prohibits, if its volume is insufficient, any propagation of projective waves of frequencies lower than 180 Hertz.

 In conventional reproduction. in the electrical bandwidth 120 Hertz - 180 Hertz) a regime of standing waves is established. The resonance frequencies depend on the dimensions on the three axes of the volume to be sounded.

 The resonance of projective waves is at the origin of an interference field. The curvilinear integral, which in principle propagates at 331 Meters per second, is fixed. The air molecules oscillate around a fixed point.

This has the effect of considerably reducing the fidelity of the entire audible spectrum.

 Above 600 Hertz the loudspeakers are such that the displacement of the air molecules becomes progressively orthogonal to the displacement of the piston. There is an appearance of a CARDIOiDIC isoptant distribution. This observation means that ACOUSTIC CURVILISM exists naturally.

The curvilinear loudspeaker ensures the transformation of a projective field of velocity into an equiprojective field of velocity. This is the reason why the device projects the molecules of air towards each other
Molecular interaction results in a conservative force that physically does not work. Its direction is the axis of displacement of the inductive piston. This conservative force is the result of a TORSEUR which propagates the molecule of air on a TROCHOIDAL trajectory of plane orthogonal to the conservative force
The TORSEUR generates two trajectories simultaneously:
- the first is RELATIVE, it is that of the
particle in a mobile rotating space instan
born of pulsation w; we call it ROULANTE,
- the second is ABSOLUTE, it is the one that is
apparent in our observation frame.

 Such is the physical difference between a projective and an equiprojective field. A conventional speaker causes a field of interference such that -the air molecules sty very little propagate A contrario CURVILIGNE enclosure causes the displacement of the molecules it induces.

 The wheel has a constant pulsation which depends only on the conditions of temperature and. pressure.

The instantaneous frequency is close to 10 Megahertz. This is actually the frequency called PLASMA in RADIOCOMMUNICATION.

 The second is apparent in our vector space.

She gives us the auditory sensation. It is circular and has a few radias for pulsation. The door is a function of the carrez root of power at the show
In this way the listener is subject to a variable power flow. All the trajectories of the molecules are tangent to the origin
if the power builds up, the apparent trajectory
tends to increase,
on the contrary, if it decreases, it tends to be
punctual.

The listener perceives this wave shift. Instant variations give it the tone of the musical program.

 Traditional stereo speakers color circular paths by twisting them by addition and subtraction of harmonics. This interaction results in the pitch of the sound.

The last advantage presented by the acoustic curvilism, will interest the professionals of the spectacle. The effect
LARSEN is one of the results of the acoustic standing wave regime. Since this is strongly attenuated, the LARSEN effect is partially suppressed.

The hanging remains at a very high level of acoustic reproduction. For a reasonable reproduction level, the user of a microphone may be located near the acoustic inductor. At a distance of a few meters from the inductor, the same user may be located in the higher level induced acoustic flux.

Claims (3)

- Claims  1 ") Device for the reproduction of low frequency acoustic waves, characterized in that it comprises a housing made of a board (2/2), allowing the arrangement of two low-frequency loudspeakers and a control electronics. adaptation of the electrical signals received from a conventional stereo amplifier.  the conventional stereo amplifier.  electrical signals to be reproduced from  the volume (3) receives the adaptation electronics  vertical holes (FA) on the board (2/2)  circulars to the local to be seen by three  two speakers and the broadcast of the waves  torsion of the acoustic powers emitted by the  the volume (2) is a resonator allowing the  (2) that separates them  acoustic waves are emitted towards the volume  your enclosures arranged in such a way  - the two designated volumes (1) are  The case has four distinct volumes such as  2 ") Device according to claim 1, characterized in that the two low frequency loudspeakers are arranged horizontally, inverted with respect to one another, not acoustically coupled by the two volumes (1) and fed by a single monophonic signal Each of the electrical coils is connected in series and in electrical phase with that of the other loudspeaker.  3 ') Device according to claims 1 and 2 characterized in that a passive filtering ink represented in the board (1/2) allows the interworking between a stereo amplifier connected to the ports (ED) and (EG) then the two conventional stereophonic speakers connected on the accesses (SG) and (SD). The signals coming out of the (SG) and (SD) adapter are greatly attenuated for frequencies below 256 Hertz. By mixing the signals absent on the accesses (SG) and (SD) with respect to the inputs (EG) and (ED) are added and presented to a complementary monophonic amplifier connected to the access (AMP). The monophonic amplifier operates on the two loudspeakers of claim 2.