SoundShield from Polaris is a digital Acoustic Shock Protection Device designed & manufactured in Australia using the latest DSP (Digital Signal Processing) technology. SoundShield prevents acoustic shrieks or high pitched tones from reaching the ear of a headset user, by detecting and instantly rejecting these shrieks within 16-32 milliseconds.

SoundShield is installed between the headset and the telephone console and is powered by 240V mains supply. SoundShield contains software which is programmable to work with all current and future headset models and PABX systems on the Australian market.

How does it work?

It Detects and Rejects Acoustic Shrieks

The SoundShield's most innovative feature is its ability to recognise and eliminate 'shrieks' - high pitched piercing sounds. A dual-band 'shriek rejector' tracks and simultaneously suppresses up to two of these sounds while preserving consistent voice quality and intelligibility to the caller.

Suppression occurs so quickly that the distressing and potentially damaging shriek is turned into a barely audible brief sound pip. This feature enables the operator to continue conversing, even if the fault in the phone network persists.

It Limits Exposure to Loud Noise

Unlike conventional analogue amplifiers on the market today, SoundShield has the ability to limit receive noise to a configurable acoustic ceiling of 80, 85 or 90 decibels.

This means that the headset user will never be exposed to noise louder than the acoustic ceiling irrespective of the volume settings, loud voices, etc. This feature is known as the Absolute Acoustic Ceiling.

It Significantly Enhances Voice Quality

Using DSP technology, SoundShield possesses superior speech intelligibility and voice clarity ahead of the conventional analogue amplifiers by providing consistent call levels.

It does this by sampling the environmental noise levels, signal and voice levels and adjusting the automatic gain control accordingly to suit the environment the caller is in.

It also features functionality to enable the user to control volume, mute and tone. All this is carried out while remaining within the acoustic limit set by the product.

Not only does SoundShield protect the user from Acoustic Shock, it also negates the need for an amplifier as it has inbuilt controlled amplification functionality.

SoundShield was originally researched, designed and developed by a collaboration between Polaris, Telstra, the National Acoustic Laboratories and CRC for Cochlear Implant and Hearing Aid Innovations (Bionic Ear Institute). SoundShield is currently being manufactured in Melbourne, Australia by Polaris.

The National Acoustic Laboratories is a division of Australian Hearing, and a government funded research facility into hearing aid innovations. NAL have researched the problem of acoustic shock extensively, and have developed the software that runs the SoundShield product. The CRC, who were collaborators in the development of the Bionic Ear, have also worked closely with NAL in the software development.

		Features : Acoustic shock protection Software Configurable for use with any Headset and any PABX Automatic Gain Control based on ambient noise levels Superior digitally processed voice quality Ring LED Call-in-progress indicator using voice detection software 3 level tone control Transmit/ Receive volume controls Headset/ handset switch Ring LED Mute indicator

Acoustic Shrieks

An acoustic shriek is an unexpected high pitched tone (HPT) or other noise (loud or soft) that may occur in telephone networks. Examples of acoustic shrieks are incorrectly dialled fax machines, maliciously generated noises such as screaming or blowing a whistle down the line, feedback or oscillations between a cordless phone and its base station, faults within the telephone line, or even callers dropping their handset on to a desktop.

The problem is not limited to any particular telephone or headset type, or any particular telecommunications network or equipment. High pitched tones are random and often cannot be traced or prevented from recurring

Acoustic Shock Syndrome

Acoustic Shock Syndrome occurs when a headset user is exposed to an acoustic shriek. It has become more common with the increase in telephone traffic and the growing number of call centres with dedicated operators around the world. Headsets tend to exacerbate the problem as they take longer to remove than handsets.

Stress and anxiety can heighten the effects of acoustic shock. One incident may lead to a feeling of apprehension about the likelihood of a recurring incident, even at a lower noise level. Likewise, a user's anxiety is further increased if volume levels must be turned up where the ambient noise level in the call centre is quite high.

Symptoms following exposure to acoustic shrieks can include: Ear-ache and nausea Headaches, jaw and neck pain Hollow feeling in the ear "Fluttering" noise in ear, leading to poor balance Burning sensation to face and head Tinnitus (ringing in the ear) and hearing degradation over time Permanent sensitivity to loud noises in general, thus affecting lifestyle Where inner ear membranes have been otherwise weakened (by ear infections or diving trauma) acoustic shock can cause tearing of the inner ear membrane One of the main issues in the cause of acoustic shock syndrome, apart from the initial high pitched tone, is the startle reflex action. Dr Harvey Dillon PhD, co-inventer of SoundShield and Director of Research at National Acoustic Laboratories, says "it seems highly likely... that the sound exposure [to an acoustic shriek] elicits an acoustic startle reflex. (The same startle reflex can also be elicited by an unexpected touch or puff of air to the eyes). When startle occurs, numerous muscles in the upper limbs, shoulders, neck, eye ....are activated. If the noise exposure is loud, and if the person is in an aroused state prior to the startle, the magnitude of the muscular response is heightened. It seems possible that the ongoing symptoms [of acoustic shock syndrome] are the after-effects on the muscles and ligaments caused by the muscles being tensed to an unusual degree..."

Affected workers may then feel hypersensitive to loud sounds that previously would have caused no problems. The fear that a shriek might reoccur lowers their threshold even further, putting them at greater risk of injury if it happens again. This is even likely to affect co-workers, who may be apprehensive about the likelihood of an incident once they are aware that it has occurred within their telephone network.