Audio Spotlighting Seminar Pdf Download
Violetta Wagganer
A seminar on AUDIO SPOTLIGHTING. Presented by RAKESH B (1BY06EC044). Under the guidance of Prof. ANIL KUMAR D. CONTENTS. INTRODUCTION THEORY WORKING COMPONENTS AND BLOCK DIAGRAM TYPES OF MODES ADVANTAGES APPLICATIONS CONCLUSION BIBLIOGRAPHY. INTRODUCTION.
ADVANTAGES Can focus sound only at the place you want. Ultrasonic emitter devices are thin and flat and do not require a mounting cabinet. Focused sound travels much faster in a straight line than conventional loudspeakers. Dispersion can be controlled - very narrow or wider to cover more listening area.
APPLICATIONS Automobiles: Beam alert signals can be directly propagated from an announcement device in the dashboard to the driver. Retail sales: Provide targeted advertising directly at the point of purchase. Safety officials: Portable audio spotlighting devices for communicating with a specific person in a crowd of people.
Hi-fi speakers range from piezoelectric tweeters of various kinds of mid-range speakers and woofers which generally rely on circuits at large enclosures to produce quality sound, whether it is dynamic, electrostatic or some other transducers- based design. Engineers have struggled for nearly a century to produce a speaker design with the ideal 20Hz -20,000Hz capability of human hearing and also produce narrow beam of audible sound.
The Audio spotlight developed by American Technology Corporation uses Ultrasonic energy to create extremely narrow beams of sound that behaves like beam of light. Audio spotlight exploits property of non-linearity of air. A device known as parametric array employs the non-linearity of air to create audible by products from inaudible ultrasound, resulting an extremely directive and beam like sound. This source can projected about an area much like a spotlight and creates an actual specialized sound distant from a transducer. The ultrasound column acts as airborne speaker, and as the beam moves through the air gradual distortion takes place in a predictable way. This gives rise to audible components that can be accurately predicted and precisely controlled.
This audio spotlight technology creates focused beams of sound similar to light beams coming out of a flashlight. Specific listeners can be targeted with sound without other hereby hearing it, i.e. to focus the sound into coherent and highly directional beam. It makes use of non- linearity property of air.
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2.2 NON-LINEARITY OF AIR
Audio spotlighting exploits the property of non-linearity of air. When inaudible ultrasound pulses are fired into the air, it spontaneously converts the inaudible ultrasound into audible sound tones, hence proved that as with water, sound propagation in air is just as non-linear, and can be calculated mathematically.
??????????? A device known as a parametric array employs the non-linearity of the air to create audible by-products from inaudible ultrasound, resulting in an extremely directive, beamlike wide-band acoustical source. This source can be projected about an area much like a spotlight, and creates an actual sound distant from the transducer. The ultrasound column acts as an airborne speaker, and as the beam moves through the air, gradual distortion takes place in a predictable way. This gives rise to audible components that can be accurately predicted and precisely controlled. However, the problem with firing off ultrasound pulses, and having them interfere to produce audible tones is that the audible components created are nowhere similar to the complex signals in speech and music.
Human speech, as well as music, contains multiple varying frequency signals, which interfere to produce sound and distortion. To generate such sound out of pure ultrasound tones is not easy.
This is when teams of researchers from Ricoh and other Japanese companies got together to come up with the idea of using pure ultrasound signals as a carrier wave, and superimposing audible speech and music signals on it to create a hybrid wave. If the range of human hearing is expressed as a percentage of shift from the lowest audible frequency to the highest, it spans a range of 100,000%. No single loudspeaker element can operate efficiently or uniformly over this range of frequencies. In order to deal with this speaker manufacturers carve the audio spectrum into smaller sections. This requires multiple transducers and crossovers to create a 'higher fidelity' system with current technology.
(Airborne ultrasounds of 28 kHz are envelope-modulated with audio signals. Inherent non-linearity of the air works as a de-modulator. Thus de-modulated sounds impinge on our eardrums. We can hear those sounds! )
Using a technique of multiplying audible frequencies upwards and superimposing them on a "carrier" of say, 200,000 cycles the required frequency shift for a transducer would be only 10%. Building a transducer that only needs to produce waves uniformly over only a 10% frequency range. ?In this technology we can ?put sound where we want?
Using sound with vision improves retention rates by up to 60%, but how do you get round the issue of noise pollution to the surrounding area? By using Audio spotlight - which concentrates the sound just as a spotlight does so only those in the "beam" can hear your message. Use it outside your shop window, or under your billboard. People can hear, but can't always know where the sound is coming from. Creative opportunities
AUDIO SPOTLIGHT TRANSDUCER
A layout is the view that each participant has of all the other participants in the meeting. The layout for a meeting is configured in advance by the administrator, but can be changed during the meeting by Host participants using SIP/H.323 endpoints that support DTMF keypad controls or by using the Connect app.
A wide range of layouts are available, including Pexip's AI-driven Adaptive Composition layout and a variety of classic layouts that have different combinations of speaker-focused and equally-sized participant arrangements. You also have the ability to define your own custom layouts.
Other layout features you can enable include showing the names of active speakers and participants as text overlays, and spotlighting (pinning) nominated participants into the primary positions in the stage layout.
It continuously analyzes each video feed from all participants and uses automatic face detection and framing to create an optimized view of that participant, or group of participants where there are several people in that video feed.
The participant is returned to the video layout if video is restored, or if any faces or movement are detected. Face detection is applied periodically on SIP/H.323 endpoints, if audio is detected (all device types), or on mouse activity (Connect apps).
In addition to Adaptive Composition, you can select from a range of other classic layouts for your Virtual Meeting Rooms and Virtual Auditoriums. These alternative layouts do not apply any face detection or framing technologies.
Custom layouts are specified through JSON configuration files that are uploaded via themes. The theme can then be assigned as the default theme or applied to specific VMRs and gateway rules as required, to control where your custom layouts may be used.
When text overlay is enabled, the name that is shown depends upon whether the participant was invited into the conference, the type of endpoint device, and whether the participant had to authenticate, as follows:
Pexip Infinity follows a set of rules to determine whether a specific endpoint is a single-screen or dual-screen device and thus whether it can send presentation content in the layout mix, or make use of multiscreen participant display:
The Pexip VMR self-service portal is a separately-installable component that allows end-users to manage their personal Virtual Meeting Room without having to send requests to their administrator to change the configuration or branding of their VMR.
The spotlight feature locks any spotlighted participants in the primary positions in the stage layout, ahead of any current speakers. When any participants have been spotlighted, the first one to be spotlighted has the main speaker position, the second one has the second position (leftmost small video, for example), and so on. All remaining participants are arranged by most recent voice activity, as usual.
Pexip Infinity's classic layout types (1+7, 2x2 and so on, with the exception of the 1+33 layout) provide similar features to Adaptive Composition in terms of showing participant numbers, lock status and so on, but these various indicators are in different positions within the layout:
When there are between one and four audio-only or inactive-video participants, each is represented by an indicator on the left side of the video window. By default this is either the audio-only icon or the video-muted icon . However, it will display the participant's image/avatar instead if it is available, such as via policy profiles or user records. When an audio-only or video-muted Connect app participant is speaking, their indicator expands to show their name in addition to the image or icon:
If there are five or more audio-only or video-muted Connect app participants, they are represented by a single summarized indicator which shows the mix of those participants. When one of the audio-only or video-muted participants speaks, the indicator expands to show their name:
All video-enabled participants in a Virtual Meeting Room or scheduled conference see the same layout, regardless of whether they are Hosts or Guests. Administrators can select the layout to use for each Virtual Meeting Room, however Hosts can change the layout during the course of a meeting.
To select the layout to be used by default, from the Administrator interface go to Services > Virtual Meeting Rooms or Services > Scheduled Conferences, select the Virtual Meeting Room, and then select one of the options from the View drop-down menu.
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