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What is an audio metric test?

An audio metric or hearing test, is part of an ear examination that is carried out to evaluate a person’s ability to hear certain sounds clearly. This is done by simply measuring the ability of sound to reach the brain. The sounds we hear start as the vibrations of fluid (air and liquid) and solid materials in our surrounding.

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The vibration of particles produces sound waves, which vibrate at a certain frequency (speed) and height (amplitude). The height of the sound wave determines how loud (volume) the sound is going to be. The vibration or speed of a sound wave determine how high or low the sound is likely to be (pitch). When these sound waves travel through the ear, they are turned into nerve impulses. These nerve impulses are then sent to the brain, which “hears” them.

How to prepare for the hearing test

No special form of preparation is required before the test. However, try to remain still and be quiet during the test to allow for accurate recording to be made. Basically, the health professional will inform you on what you are required to do during the test.

How is the test performed?

These tests measure your ability to hear sounds that reach the inner ear through the skull (bone-conducted sounds), and sounds transmitted through the inner-ear canal (air-conducted sounds). There are three main classes of audio metric tests.

Whispered speech test

Also referred to as speech audiometry, this test determines how well you perceive the sound of words. You will be asked to wear headphones and sit in a soundproof booth. The health professional will then recite a list of words at different decibel levels.

The audiologist will ask you to repeat the words aloud. If you haven’t heard the word clearly, the professional will whisper back a bit louder. This test takes approximately 10 minutes to administer.

Tuning fork test

This procedure involves making a two-pronged device vibrate to produce a tone. The tuning fork is tapped and held in the air on each side of the head. The purpose of this test is to assess how sound moves through your ear canal.

The test measures your ability to hear by air conduction. After being tapped the fork is placed against the mastoid bone behind each ear to test bone-conduction.

Pure tone audiometry

This test is carried out using an audiometry machine. The audiometer plays tones that vary in pitch and intensity. During the rest you will again be required to wear headphones while sitting in a soundproof booth.

Pure tones of controlled pitch and intensity are delivered to one ear at a time to test air conductivity. You will be asked to press a button or raise a hand when you hear a sound. The minimum volume required to hear each sound is then graphed. A bone oscillator is placed against the mastoid bone of each ear to test bone conduction.

What does the test show?

Pure tone audiometry, charts the hearing level of different tone intensities in both ears. On an audiogram chart, blue X’s show the left ear’s results and red O’s show the right ear’s results. Hearing loss is categorized as:

-Normal: less than 25 dB HL

-Mild: between 25-40 dB HL

-Moderate: between 41-65 dB HL

-Severe: between 66-90 dB HL

-Profound: more than 90 dB HL

Normal results

So what exactly is normal results? This is the ability to:

-Hear a tuning fork through air and bone.

-Hear a whisper, normal speech or the ticking or a watch.

-Hear tones from 250 Hz to 8,000 Hz at 25 dB or lower.

Abnormal results

As noted earlier, there are different degrees of hearing loss. In some levels, patients lose the ability to hear high or low tones, and in others patients lose only bone or air conduction. The following conditions are known to affect test results or cause hearing loss.

-Acoustic trauma

-Chronic ear infections

-Acoustic neuroma

-Age-related hearing loss


-Alport syndrome

-Meniere’s disease

-Head injury

-Ruptured to perforated eardrum

-Occupational hearing loss


Some medications can affect the inner ear e.g. certain antibiotics (such as gentamycin or neomycin), large doses of salicylate (e.g. aspirin) and diuretics, which cause hearing loss.

Who should the test be carried out on

-Everyone, as part of a routine examination.

-People who are often exposed to loud sounds, maybe in the course of their work.

-Children or teenagers who can’t hear well in class hence have problems speaking.

-People who feel that they are experiencing some hearing loss maybe due to age. 

Why Spending Money On A Quality Hearing Aid Is Worth It

The sticker price of advanced digital hearing aid systems still seems to shock even the educated group of consumers. Many people hesitate to invest in such an essential product because of the high price. Furthermore, when local newspapers advise peppered low cost hearing aid, the whole scenario of spending money on advanced aids become all the more questionable.

Read our full investigation on the cost of hearing aids here

Honestly speaking, basic hearing aids can be built for a low cost. But the cheap version compromise on either of the one essential factors i.e effective, appearance, and safety. If you are looking for hearing aids that can offer excellent quality sound and also do not show up like traditional aids, then you ought to spend a little more than usual.

Why Do Hearing Aids Cost So Much?

Today, there are many styles and types of hearing aids available in the market. The average cost might range from $795 to $3500, depending upon the style and features you opt for. This clearly means that you can now hear and speak clearly for as little as 1 Dollar per day.

The final cost is determined by the respective features and functions offered by a particular model of hearing aid. The more features you want, the higher you’re likely to pay. Nowadays, more and more people are opting for invisible hearing aids that also work effectively across a broad spectrum of listening environments. These kinds of hearing aids are comparatively costly than cheap imitations. Let’s take a look at some factors that contribute to the price of hearing aids:

  • Technology
  • Durability and reliability
  • Personal fitting
  • Professional costs
  • Product lifecycle
  • Manufacturing costs
  • Marketing costs
  • Warranty costs
  • Free trial costs
  • Inflation
  • Customization
  • Hearing-aid Styles and Features

Digital hearing aids come in a number of styles, offering a plethora of features to deliver excellent sound quality and clarity of speech. Some of them are small enough to fit inside your ear canal, while others fit partially. Generally, the smaller a hearing aid is, the expensive it is going to be due to the complexity of technology involved. The following are common hearing aid styles.

Completely in the canal

Almost invisible hearing aids are molded to perfectly fit inside the ear canal. A completely-in-the-canal hearing aid:

  • Almost invisible.
  • Prevents wind noise.
  • Easy to use with the telephone.
  • Uses smaller batteries.
  • Lacks volume control or directional microphones

Partial In-the-canal Hearing Aid

A partial in-the-canal hearing aid fits partly in the ear canal. It is designed to improve mild to moderate hearing loss. The features include:

  • Less visible in the ear.
  • Compatible with telephone use.
  • May not be suitable for very smaller ears.
  • Easy to access volume control features.


The half-shell hearing aid fits into the lower portion of the outer ear. This style of hearing aid is appropriate for moderate hearing loss. A half-shell hearing aid includes:

  • Easier to handle.
  • Directional microphones.
  • Volume control.
  • Fits most ear sizes.

Full Shell

The full-shell hearing aid fits most of the lower portion area of your outer ear. It is an appropriate style for people with mild to severe hearing loss. A full-shell hearing aid:

  • Is more visible as compared to smaller versions.
  • May pick up wind noise.
  • Easy to adjust volume control.
  • Uses larger batteries – last longing and easy to handle

Behind the ear

Behind the ear hearing aids is placed over the top of the ear and fits inside the ear canal. It is suitable for almost all types of hearing loss.  A behind-the-ear hearing aid:

  • It is the most visible type of hearing aid.
  • Delivers more amplification
  • Ample of adjustable features to fit individual requirements.
  • May pick wind noise as well.

Concluding remarks 

With so many styles and features to choose from, you should keep in mind that buying the best one can be tempting as well as costly. However, you can minimize the cost by opting for only those features that are suitable for you. 

All type of hearing aids contains essential parts, such as an amplifier, a microphone, a receiver, volume control and a battery. The additional features should depend on your lifestyle and severity of hearing loss. If you demand the absolute product with all kind of advanced features, it’s going to cost you more and that’s true of everything, even the hearing aids.

How do Digital Hearing Aids Work?

Recent years have seen an unprecedented growth in technology used in hearing aids. Hearing aids have proven themselves to be life changing instruments that have helped people with reduced hearing power to communicate easily and participate in day to day activities more effectively than they could without it. The latest models have such a discreet size that they are almost undetectable and produce much superior results than their counterparts.

For more information on specific models of digital hearing aids click here


The technology behind hearing aids has constantly evolved and has served a wide array of choices for users ever since the first fully digital hearing aid was produced in 1996. There are a number of people who had set aside their hearing aids a number of years ago due to dissatisfaction with them but with the advent of digital hearing aids they have again subscribed to them only to experience enormous user satisfaction in terms of size, shape, sensitivity and amplification.

How do digital hearing aids work?

The basic function of a hearing aid is to amplify sound and improve comprehending capabilities of individuals who have suffered hearing loss due to some damage to the sensory cells of the inner ear. The amplified vibrations are converted to signals and passed to the brain by the surviving cells. It goes without saying that more the damage, more will be the amplification required.

All hearing aids, digital or analogue, consist of four basic parts viz. a microphone that lets the sound enter the aid, an amplifier to increase the volume, a speaker to change electric signals back to sound and a set of batteries to power these devices.

Digital hearing aids work with the help of a computer chip which analyses the sound received depending upon the listening power of the person as well as the hearing loss suffered. Subsequently it amplifies the sound and accommodates for the pitch and volume of the incoming sound. They even make adjustments for feedback and can also be programmed for several listening environments.

This chip is also tasked to store the information on hearing loss and also about personal preference regarding the working of the hearing aid. Such power of personalisation greatly increases the performance of the machine and increases the chances of success. There are several levels of technology in digital hearing aids and each of them drives the price of the hearing aid.

Step by step workings of a digital hearing aid:

1. The microphone first turns the sound into an electric analogue signal.

2. Ant-aliasing filter eliminates inaudible frequencies to avoid confusion to the converter.

3. Thereafter the signal is sampled at a certain rate measured in “number of times per second”; say 10,000 times per second or more.

4. The sampled signal then allows the A/D or Analogue to digital converter to convert electric signals to digital ones.

5. The microprocessor works on the digital signal.

6. D/A or Digital to Analogue converter again converts the digital signals that have been processed by the microprocessor into analogue signals.

7. Anti imaging filter then smoothes out the signal to ensure that it sounds natural.

8. The receiver/speaker converts the electric analogue signal back to sound.

Frequency Compression Technology

A recent breakthrough in digital hearing aid technology is Frequency Compression technology. It may happen that a person’s hearing capability in certain frequency ranges is beyond any benefit from the amplifier. In such cases, use of Frequency Compression technology can yield results. Frequency compression squeezes down the high frequency sounds into mid frequencies which fall within the scope of amplification by the amplifier. This results in better speech intelligibility and less chances of feedback.

Cost Vs Technology

With so many options available in the market, each claiming to better than the rest, it is imperative that you carry out a wise analysis of each of them before shelling out money for them. Each level of technology eases a different level of hearing loss and comes at a different price.

The cost of digital hearing aids varies from product to product and depends on two major functions: the technology employed and the quality of parts used. A reasonable balance of both these functions is likely to provide you a hearing aid that suits you both in terms of utility and expense. The cost of hearing aids may range from a several hundred to several thousand dollars. Extra features such a remote control may cost you extra.

While this information on working of a hearing aid will definitely explain the benefits of digital technology in hearing aids, it is wise to experience it yourself to understand your hearing aid better.

Hearing Aid Buyer Today is an online magazine that reviews digital hearing aids available today. Click here to read some digital hearing aid reviews. 

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