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Acouspade Classic - directional sound system

ACOUstic SPAce DElimiter – Directional Sound System

The Acouspade Classic™ hyper directional sound system enables you to direct an audio beam to a specific point in the environment, thus making your content audible only at that specific location. While conventional sound systems will fill the whole area with its audio content, Acouspade™ puts you in control of where the audio can be heard, making it possible to address the public precisely where you intended to.

The Acouspade Classic™ speaker radiates sound in one direction only – as opposed to conventional speakers, which spread the sound into all directions. Acouspade™ acts like an audio spotlight and allows you to create your personal audio zone or enable different audio zones to co-exist in the same physical space, while preventing the different acoustic contents from mixing and interfering. The directional sound beam created by Acouspade can cut through noisy environments and deliver a headphone-like experience for the listener.

Acouspade-Classic-spotlight-audio

Applications

  • Retail
  • Digital signage
  • Museum and gallery installations
  • Fairs and trade shows
  • Digital kiosks
  • Libraries
  • Automotive applications
  • Slot machines
  • Bars, restaurants
  • Hearing aid
Acouspade enables the use of acoustic advertising space by providing a solution to separating acoustic spaces of different audio sources in close proximity. It enables the creation of separated audio zones – filled with different acoustic contents – sharing the same physical space.

Acouspade Classic – mounting options

Acouspade-c-mounting

Spotlight mode

In case the Acouspade directional speaker is mounted on the same wall – on top or bellow the digital sign, it needs to point diagonally downwards or upwards respectively, in order for the directional audio beam to reach all possible heights of users. In this mode the sound can not always be heard at the exact same spot, since the listening spot will depend on the users height. In case of a digital-signage situation this should not be a problem since the listening spot will always be in front of the digital screen, but the distance of the sweet-spot from the screen will be determined by the person’s height and will vary within 1 to 2 meters. This mounting mode will also create more audible artifacts around the room, since the first surface (floor or ceiling) will be hit in a specific angle, which will reflect the sound to the next surface, and so on.

Sound shower mode

Ideally, the Acouspade directional speaker should be mounted on the ceiling, facing the floor. This creates a typical “sound-shower” situation, making the sound audible only at one spot in the room, while enabling it to be heard by people – of all heights – at the same spot. The sound-shower mode is also the best solution to minimize reflections of the sound and its audibility at different locations around the room. The sound starts to travel from the ceiling, bounces off the floor and is reflected back to the same spot at the ceiling, and so on.

Virtual speaker mode

A very interesting mounting situation is the “Virtual speaker mode”, where the speaker is not pointing directly towards the user. Instead, the speaker is pointing towards the digital sign, (or any other object that you want to draw attention to, by using directional sound) from which the sound beam bounces and arrives at the user indirectly. This situation makes it appear as if the sound originates from the object that it is being reflected from. The actual sound source remains hidden and is not noticed by the user.

Features

The Acouspade™ speaker offers highly directional distribution of sound, which is reproduced clearly – without distortion – even at high volumes. The sound is of high-quality, with low noise and great frequency response, which includes authentic reproduction of bass notes and frequencies as low as 150 Hz.

System

The new Acouspade Classic is a fully integrated system. The emitter already contains the amplifier and the signal processing system. It is a simple plug&play solution. Just connect your audio source device (such as portable music player, laptop, DVD-player etc.) to the speaker audio inputs and you are ready to go.

Colours

Acouspade is available in two different colours: black and white.

Acouspade Classic™ vs. Audio Spotlight®

A comparative research study on directivity characteristics of directional speakers, was conducted by JOANNEUM RESEARCH DIGITAL – Institute for Information and Communication Technologies in 2014. The results clearly show that the Acouspade directional speaker outperforms the Audio Spotlights by Holosonics in terms of directionality. Of all three tested speaker models, Acouspade creates the most narrow beam of sound. A paper about the results was published at the 40th Annual meeting of the German society for Acoustics.
Research study
Acouspade_vs_Audio_Spotlight_sm

Acouspade classic – Technical Specification

By focusing sound in a narrow beam, Acouspade™ is able to place sounds at any desired spatial location, making it possible to deliver acoustic information to the public precisely where it is needed.

Acouspade radiation patterns

Electrical

  • Input voltage: 230V or 120V, 50/60 Hz
  • Power supply: 24V/1A

Dimensions and weight

  • Speaker dimension: ø270 x 19 mm
  • Speaker weight: 880 g

Operating environment

  • Temperature: -20°C to 60°C (-4°F – 140°F)
  • Humidity: 0 – 95% (non-condensing)

Ultrasonic and DSP processing

  • Carrier frequency: cca. 40 kHz
  • Modulation method: AM

Audio

  • Input impedance: 10k Ohms
  • Typical input signal: 160 mVrms
  • Frequency response: 150 Hz to 16 kHz
  • Max speaker output: 90 db @ 1kHz/1meter

Connectors

  • Audio input: 2x RCA

Colours

  • Black
  • White

Directional sound systems, also called Parametric Acoustic Arrays (PAA) have found their way into many practical audio applications in the last decade or so, due to their high directivity. Parametric acoustic arrays have come a long way since their introduction by Peter J. Westervelt in 1963. Due to their high directivity and almost nonexistent side lobes, many applications have been developed using PAA ranging from underwater applications, speech and music reproduction to medical applications. The two main challenges that each PAA system has to overcome are low conversion efficiency of the high frequency primary waves into secondary (audible) waves and the distortion of the desired (modulation) signal.

A parametric acoustic array is created by emitting an intense and highly directed ultrasonic sound beam consisting of a carrier wave and signal components introduced by one of the various modulation types. The carrier interacts with other spectral components of the ultrasonic sound beam due to the nonlinearity of air at high acoustic sound pressure levels (SPL) and generates new spectral components along the ultrasonic beam.
Directional sound operating principle
These secondary waves contain audible spectral components related to the difference between the carrier and side bands. The nonlinearity of air also generates higher inaudible frequencies which are quickly absorbed due to the high absorption coefficient at high frequencies. Thus the ultrasonic source creates a beam of ultrasound which acts as a virtual array of sound sources.

An ultrasonic sound beam is usually generated by piezoelectric or electrostatic transducers. The mechanical construction of the piezoelectric ceramic transducer that is used in the Acouspade directional speaker is shown below. The active element is a thin disc made of Lead Zirconate Titanate (PZT) ceramics. The applied voltage causes the disc to expand and contract. The center of the PZT disc is thus displaced vertically up or down depending on the polarity of the voltage. The mechanical properties of the materials used as well as their physical dimensions determine the resonant frequency and bandwidth of the transducer.

These transducers can continuously transmit a SPL of about 120 dB at 40 kHz when driven by 10 VRMS. PZT transducers have a small bandwidth and can be driven with a maximum driving voltage of 20 VRMS, which generates up to 126 dB SPL.

The main functional units of the modulator/amplifier in an ultrasound-based directional sound system are:

− input amplifier and signal conditioner
− low distortion quadrature oscillator
− integrated multiplier with adder
− D-class power amplifier
Directional sound signal processing system
Excerpt from the paper “Sources of Noise in Practical Implementations of Modulators/Amplifiers for Parametric Acoustic Arrays”, by authors: Matija Pirc and Andrej Levstek; Published at MIDEM 2014 – 50th International Conference on Microelectronics, Devices and Materials

The Acouspade directional speaker is a result of several years of research and development. The speaker system exhibits a highly directional sound-field distribution, creating a laser-like sound beam, that can be directed precisely to the location where it is needed. The sound is of high-quality, with low noise and great frequency response, which includes authentic reproduction of bass notes and frequencies as low as 150 Hz. The speaker itself is easy to use – you only need to plug the audio output of the source device (such as portable music player, laptop, DVD-player etc.) to the speaker audio inputs and you are ready to go.
Acouspade Classic Focussed Speaker side view
Acouspade Classic – side view
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