Audiology/Hearing Aid/Sound Glossary of terms produced by the ISVR

Brilliant resource:

A short abstract of the As below. All copyright per the original authors and the ISVR.

Here

A

acoustic admittance		Reciprocal of acoustic impedance.
acoustic coupler		A cavity of specified shape and volume which is used for the calibration of an earphone in conjunction with a calibrated microphone to measure the sound pressure developed within the cavity. Compared to an artificial ear, a coupler embodies only a rough approximation to the acoustic properties of the human ear but has the advantage of simple design and construction.
acoustic feedback		In hearing aids, the condition in which the amplified acoustic signal leaks from the ear canal, is picked up by the microphone and then re-amplified, resulting in a howling or whistling sound. The term is also applied to the feedback sound itself.
acoustic gain		As applied to the testing of a hearing aid, the difference between the output sound pressure level developed in the acoustic coupler or occluded-ear simulator and that measured at the position of the hearing aid microphone. The particular conditions of test have to be specified. Sometimes called transmission gain.
acoustic impedance		Quotient of a sound pressure by the volume velocity produced by it.
acoustic nerve		Alternative term for the cochlear nerve.
acoustic neuroma		Common term for a non-malignant tumour on the VIIIth cranial nerve which, by invading the intracranial spaces, becomes life-threatening. It causes ataxia and neural hearing loss. Also termed vestibular schwannoma or acoustic neurinoma.
acoustic reflex		Contraction of the middle-ear muscles, stapedius and/or tensor tympani, as a normally bilateral response to an acoustic or other eliciting stimulus (which is not necessarily bilateral). The amount of contraction and subsequent acoustic reflex decay (ARD) are measured by immittance audiometry. The reflex is commonly described as ipsilateral or contralateral, depending on which side the response is observed relative to the stimulus.
acoustic reflex threshold	ART	Of an ear and for a specified type of sound, the lowest level of that sound which elicits the acoustic reflex. The reflex is recognized by a change in aural immittance as an increasing stimulus level reaches and surpasses the acoustic reflex threshold. The ART is conventionally expressed in terms of hearing level but use of sensation level is an aid to diagnosis.
acoustic trauma		Instantaneous injury to, or destruction of, a component or components of the auditory system resulting from exposure to a very high transient sound pressure, e.g. from explosion or weapons fire. The term is not to be confused with noise-induced hearing loss from chronic exposure or with barotrauma.
action level		One of three levels of noise specified in the Noise at Work Regulations 1989. First action level: a daily personal noise exposure of 85 dB(A); second action level: a daily personal noise exposure of 90 dB(A); peak action level: a peak sound pressure of 200 Pa. These levels define various actions to be taken by employer and employee.
admittance		...............

Which? the consumer affairs people stepping in to the industry with a guide...

Here

Covers all the basic pros and cons of the industry in the UK.

Brownian motion and hearing aid mic noise.....

......explained a bit further for Hearing Aid Forums readers.

That's not static, it's the noise floor - caused by air particles hitting the diaphragm of the mic (Brownian motion).

The 'only' (perhaps somebody else has now) people to have dealt with this properly so far are Widex. If you're an engineer you'll get the explanation. 

All* the mics used in hearing aids are based on the electret condenser principle. You basically charge a gold/mylar film to a high voltage (permanent) and then move it back and forth over a backplate. The back plate is connected to a MOSFET gate which allows the incoming voltage to be 'switched' on and off. Hence your mic signal. The diaphragm mass is as small as possible to reduce skeletal vibration transfer and be as sensitive as possible. It's also got to be as near to the back-plate as practical to ensure the best attraction/repulsion.

The downside of making the diaphragm smaller is that the effects of Brownian motion become more pronounced and you create a noise floor of 20-30dB before the amplifier stage, especially with the smallest diaphragm mics. 

Widex uses a clever system to get around this - by splitting the input (1.0-1.2V) voltage at x GHz into an AC voltage it creates an effective 2.0-2.4V potential across the aid. Which you will know benefits the system as V rises, power consumption falls. The particular benefit with this system is that higher voltage allows the mic diaphragm properties to be altered - moved away/different mass - which can be used to alleviate the effects of Brownian motion. Subsequent noise floor levels are now around 16dB.

Furthermore the Widex system is 16-Bit (96dB range) and only starts sampling at 17 dB - so the entire mic is effectively ignored by the hearing aid UNTIL it starts producing a signal in relation to a real output.

*AFAIK

A different lifestyle with hearing?

Interview by Jeremy Vine on BBC Radio2.

“Would I be a better musician if I had not lost my hearing?”

Evelyn Glennie, the world’s first solo percussionist, ponders the biggest question of all: what makes us human?

Remember her barefoot, beating the drums at the London 2012 Olympic Ceremony? Today, she talks to Jeremy about sound, life and social listening.

You’ll be able to listen to Evelyn again, and to the whole archive featuring philosophers, comedians and a Rabbi here:http://www.bbc.co.uk/programmes/p019yl4r

Libby Horns and tubing article from the man himself.

Article that covers the changes to a BTE sound output that can be achieved with different tubing set-ups.

http://www.cylibby.com/horn/

Inside the world's quietest room

Extra low power Bluetooth Chips.....

Coming to a hearing-aid near you soon?

With SmartBond, Dialog Semiconductor has released what the company claims to be the world's lowest power and smallest Bluetooth Smart System-on-Chip (SoC), which more than doubles the battery life of an app-enabled smartphone accessory or computer peripheral in comparison to competing solutions on the market.

Designed to connect keyboards, mice and remote controls wirelessly to tablets, laptops or Smart TVs, the part number DA14580 will enable consumers to use innovative apps on their smartphones and tablets connected with watches, wristbands and smart tags, to “self-track” their health and fitness levels, locate lost keys and much more besides.

SmartBond unique low power architecture draws just 3.8mA at transmission and reception, 50% less than other Bluetooth Smart solutions on the market according to the manufacturer, with a deep sleep current of under 600nA. This means a 225mAh coin-cell battery in a product sending 20 bytes of data per second would last 4 years and 5 months in comparison to just 2 years with previous generations of Bluetooth Smart technology.

The DA14580 features a Power Management block, including a DC-DC converter and all the necessary LDOs, reducing the need for external components and the overall bill of materials. By precisely switching on and off power delivery to each block on the chip, Dialog is able to reduce energy consumption to a bare minimum.

SmartBond works at much lower voltages than was previously possible, down to 0.9V, enabling the use of just one alkaline or NiMH cell AA battery instead of two in computer or smart TV peripherals. The DA14580 comes in three different form factors, the smallest Wafer-Level Chip-Scale package measures 2.5x2.5x0.5mm.

DA14580 information page
DA14580 product brief

Visit Dialog Semiconductor at www.dialog-semiconductor.com

Find more datasheets on products at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

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This article originally appeared on EE Times Europe.