The operation in this case is the same as that described with reference to FIGS. Then, the pulsator 38 can be used for starting the sound generator by supplying to the space 27 blows of pressurized air of substantially the same frequency as the fundamental tone of the sound generator said air blows actuating the membrane 20. 2. 6 is an axial cross-sectional view of a low-frequency sound generator according to the invention of a somewhat modified embodiment, a pressurized gas supply and control system being shown diagrammatically, and. The utility model discloses a rotary sound wave generator of a variable-mass low-frequency sound wave soot blower, which is composed of the following components: a static cone sound generating disc and a dynamic cone sound generating disc. So with reversed polarity try playing one speaker at 50hz while the other at 60hz hopefully giving you a 10hz overall sound. The low-frequency signal generators. 3 the passage area between the compartment 17B and the resonator tube being increased, which means that the pressure in the closed end of the resonator tube will be increased. This is a continuation of application Ser. for sooting boilers, furnaces and processing apparatuses it is the intention that it should be operated intermittently and in that case it may happen that the sleeve-type slide 15 when it has been at rest and is to be operated again, jams on the socket 33 particularly if the sound generator is being used in a corrosive environment so that the faint sound pressure produced by the passage of the pressurized air through the narrow openings uncovered at the transverse bores 34 said openings being of the order 1 mm will not be sufficient to overcome the rest friction of the movable system and to start the membrane movement. The air cushion in the embodiment according to FIG. In air of the temperature 20° C. the propagation rate of the sound wave is 340 m/sec. The gas pulses develop standing sound waves in the resonator tube which provides a varying gas pressure. The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.001 Hz. Pressurized air can be supplied to the tank 51 from the distributor 50 also via an adjustable choked shunt 54 through a connection between the distributor 50 and the tank 51, said connection being parallel to the connection via the solenoid valve 52. 2, in which the pressure in the closed end of the resonator tube is as large as the surrounding pressure, the slide 15 should be in a position wherein the compartment 17A is disconnected from the resonator tube 10 due to the fact that the communication through the opening 19A and the control opening 16 is interrupted, the compartment 17B, however, communicating with the interior of the slide through the opening 19B and the control opening 16 and thus with the interior of the resonator tube through a narrow opening 22. The LF generator can memorize the settings of … Additionally, pick from a wide variety of … generation, Oscillatory fluid stream driven sonic generator with elastic autoresonator, Sonic generator for the agitastion of fluids, <- Previous Patent (Inflatable reversibl...). FIG. 5 and 6. A tube forms a simple and cheap resonator but it can be replaced by other resonators, e.g. If the resonator tube 10 of the sound generator is inserted into a space such as a boiler or furnace wherein the pressure is above or below the surrounding atmospheric pressure, a static pressure difference over the membrane 20 will be obtained if the space 27 is connected to the surrounding atmosphere in the manner shown in FIG. In the low-frequency generator, it is possible to smoothly adjust the output voltage by means of a dial indicator. Simply tap on the sound wave icon and pick between sine, square, sawtooth or triangle. By depending on its frequency component and sound level, it is different the degree of influence on the human body and the noise sensation. If this probe does not sense a movement of the membrane a signal lamp 48 will be illuminated. Audio Frequency Generator Software are software which uses the sound card of the PC to generate audio frequencies. Description: - a 20-segment bargraph display with peak hold and an alphanumeric display for instrument settings and precision measurements. In the closed end 12 there is provided a feeder 13 controlling the supply of pressurized gas (operating gas) to the sound generator, and usually pressurized air is supplied although other gases can of course be used such as inert gases. 5 is an enlarged detail view of a constructive embodiment of the feeder, FIG. FIG. Online Tone Generator. © 2004-2021 FreePatentsOnline.com. It's free, simple and no sign up required. Online Tone Generator utilises HTML5 and the Web Audio API. It has been found that the results in sooting or cleaning of boilers, furnaces and processing apparatuses by means of sound can be considerably improved by using intense pulses or vibrations of these low frequences, but no suitable device of industrial utility has been available so far. A low-frequency sound generator for generating intense sound, which generator includes an open resonator tube. 6 discloses a further refinement in the sound generator according to the invention, viz. All rights reserved. You can mi… Pressurized air (or another gas) accordingly can pass through the narrow opening 22 from the compartment 17B via the slide 15 into the resonator tube 10, and when air is passing through the feeder and the resonator tube low-frequency sound will be generated by turbulence and friction of the air flow. There is thus provided a feed-back system in which the supply of pressurized gas is brought to follow the variations of the sound frequency . To play a constant tone, click Play or press Space. 2 and the fans 18A and 18B have just been started, a faint low-frequency sound will be generated in the resonator tube 10 by the air flow. A wide variety of low frequency sound generator options are available to you, such as ac single phase. When the sound generator is used e.g. How low can you go? During the rest period when the valve 41 is closed a minor air flow is supplied to the sound generator through the shunt 44 and this reduced air supply is provided in order to cool the slide 15 and the membrane 20 and also in order to protect the slide and the socket 33 from dust. Try Acoustic Panels. a pneumatic pulsator 38 which is connected to the space 27. One condition that must be fulfilled if this movement is to be induced is, however, that the movable parts of the feeder 13 have a natural frequency higher than the frequency of the fundamental tone but lower than the frequency of the first harmonic. When the sound pressure in the closed end of the resonator tube is at maximum (above the atmospheric pressure) the movable slide 15 will be displaced to the right against the bias of the spring 21 to the position shown in FIG. 1 is a diagrammatic side view of a sound generator according to the invention. Sounds above 20 KHz—our upper range of hearing—are called ultrasonic. You will hear a sine wave start at 150Hz and gradually decrease to 1Hz over the course of 60 seconds. This sound provides an oscillating movement of the movable part; the sound pressure in the resonator tube will increase to reach, after a certain period, a continuing condition wherein an intense low-frequency sound is generated in the sound generator. The membrane 20 therefore provides a positive feedback of sound pressure in the resonator tube 10 to the feeder 13. Moreover, it is difficult to manufacture thin membranes which have the same spring rate in both directions. Privacy Policy If the total spring rate should be about 40,000 N/m the membrane per se thus has to contribute to a minor extent to said spring rate. If the temperature in the resonator tube is changed, also the propagation rate of the sound wave will be changed providing a change in the frequency according to the above-mentioned relationship (3). In the embodiments described the slide 15 is returned by the inherent spring action of the membrane 20 only or by this spring action combined with the air spring action in the space 27, but it is also possible to arrange a mechanical spring at the right side of the membrane 20 corresponding to the spring 21 in FIGS. E.g. Generatosaur - low frequency signal tone generator Generatosaur is a free software that turn your soundcard into a low frequency tone generator. As mentioned above, the sound generator usually is operated intermittently and the operating and rest periods are adjusted by means of the timer 45 the valve 41 being opened during the operating period. DUNNER filed June 29, 1978, now abandoned. FINNEGAN, HENDERSON, FARABOW, GARRETT (WASHINGTON, DC, US), Click for automatic bibliography From the tank 51 there is provided a connection 53 to the socket 33. Hopefully high decibel low frequency waves will be left. A pipe 31 is connected to the end cover 25 the outer end 32 of said pipe being adapted to be connected to the fan 18B or other source of pressurized gas while the remaining part of the pipe forms a socket 33 projecting freely into the resonator tube. LRAD Sound. The tone will continue until the stop button is pushed. A low-frequency sound generator for generating intense sound, which generator includes an open resonator tube. This page contains a low frequency sweep and a series of tones for testing the response of subwoofers. They are great drywall alternatives and ideal if you don’t want to do major structural changes to your … 134/1, 181/.5, 116/137R, 116/DIG.18, 116/DIG.27, 181/.5, 134/1. Furthermore, the mechanical feeder described herein, which includes a membrane, can be replaced by an electro-mechanical unit, a microphone e.g. During the rest periods when the solenoid valve 52 is closed the membrane 20 and the slide 15 are kept moving by a choked air flow passing into the tank 51 and then to the socket 33. The Sonic Nausea Device generates a unique combination of ultra-high The invention supplies this demand by a low-frequency sound generator of the type referred to above for generating intense sound of low frequency, which has obtained the characteristics according to claim 1. 3 and 4 are views similar to FIG. At 500 KHz and higher, we label sounds as megasonic. These sockets are covered by cylindrical caps 29 each socket and the associated cap forming a labyrinth passage 30 which provides free communication between the space 27 and the surrounding atmosphere dirt being prevented from entering said space. Since there is no direct communication between the space 27 and the surrounding atmosphere in the embodiment according to FIG. Let us know in the comments section at the bottom of the page. When the sound generator is operated the solenoid valve 52 is open and the pressurized air for operating the sound generator thus passes through the tank 51. This page contains a low frequency sweep and a series of tones for testing the response of subwoofers. Low frequencies have stronger oscillatory wave to the brain through skull and other bones. You will hear a pure tone sine wave sampled at a rate of 44.1kHz. 18, 138, 126, 51-52. If the membrane is made too thin, the spring rate may be too low in relation to the mass of the membrane, which provides a too low natural frequency. In the constructive embodiment according to FIG. Thus, it will be seen that at the start of the sound generator when the movable part of the feeder (the membrane 20 and the slide 15) is at rest in the position of equilibrium thereof according to FIG. 7 the feeder 10' is mounted as a separate unit to the resonator tube 10 and the same arrangement can be provided in the embodiments according to FIGS. (“Flat frequency” means just that frequency and nothing else.) It is desired to use a thin membrane in the sound generator according to the invention, but the thinner the membrane the lower the spring rate. 2 to 4, as mentioned above. The only special requirement mentioned for the power amp is that it feature a flat frequency response at 10 Hz. Sounds below 20 Hz are called infrasonic sound or infrasound. Means in … Audio Frequency Generator Software are software which uses the sound card of the PC to generate audio frequencies. Low-frequency signal generators are used to regulate and adjust systems and devices that are used in the radio electronic industry, in communication devices, in various automatic, computing, measuring devices, and in the instrument-making industry. The sound thus generated acts on the closed end 12 of the resonator tube 10 at a varying pressure and the pressure variations thus produced in the resonator tube provide a reciprocating axial movement of the membrane 20 and accordingly of the slide 15 at a a resonant frequency of the resonator, for example, the frequency of the fundamental tone said latter frequency being dependent on the length (l) of the resonator tube 10 as explained above. The frequency can be inputted through input devices like the mouse and keyboard.and levels can be controlled as well. No. 7 is a fragmentary side view, partly an axial cross-sectional view of a further modified embodiment of the low-frequency sound generator according to the invention. We have also provided a series … Means in the resonator tube is operable in response to changes in the gas pressure to provide positive feedback of the sound pressure in the resonator tube to the feeder system at a resonant frequency of the resonator tube. The frequency can be inputted through input devices like the mouse and keyboard.and levels can be controlled as well. It started off all of a sudden one day in the early hours of the morning, as it woke both myself and my partner. These frequencies range from 100 to 15000 Hz. A movable part 15 is arranged for axial displacement in the stationary part said movable part being formed as a sleeve-type valve slide having a control opening 16. An equalization of the pulsation of the pressurized air will be obtained thereby so that a smaller dimension of the conduit 40 can be used than if said conduit is connected directly to the socket 33. A spring can be provided at the right side of the membrane 20, corresponding to the spring 21, but the slide 15 can also be returned by the inherent spring action of the membrane only. You will hear a sine wave start at 150Hz and gradually decrease to 1Hz over the course of 60 seconds. Acoustic foam panels are highly effective in blowing bass noise and other low-frequency sound waves. Thus, sound could be generated in a resonator tube having a length of 5 m by supplying air pulses of the frequency 17 cps. I was convinced the noise (rather like a low generator type noise but at times it would go wild and sound like a loud engine running) was coming from nearby mobile phone masts.

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