What is the difference between a 1.5 and 2-channel audiometer?
Audiometers come in different variations depending on their application. Historically, clinicians classified an audiometer as a screener (1-channel) or as a diagnostic device with two independent channels (2-channel). The main differentiator depended on whether we could perform masking.
This difference was key. It identified whether a system was used primarily to identify hearing loss or would allow for further investigation into the type of loss. The latter would provide relevant data to use when planning patients’ rehabilitation and fitting hearing aids.
Audiometers have evolved, and in recent years developers introduced new classifier: a 1.5-channel model. A 1.5-channel audiometer has many features found in a 2-channel audiometer. So, it is important to understand their differences to avoid confusion.
What is a 1.5-channel audiometer?
The common misconception is that a 1.5 channel audiometer is significantly different to a 2-channel audiometer. However, technology now lets a 1.5-channel audiometer do many functions of a 2-channel audiometer.
Regional preference often determines the terminology people use to describe the device. In some international markets, people sometimes refer to a 2-channel audiometer as a 1.5-channel audiometer.
These audiometers have the specific function of delivering the tone to the first channel and masking to the opposite channel. In this situation, the label 0.5 identifies the second channel because you use it purely for masking. There is also a direct focus on core audiometry with applications towards:
- Tone audiometry with masking
- Speech audiometry
- Free-field audiometry (speech and tone)
- Basic paediatric testing
- Hearing aid dispensing
What is a 2-channel audiometer?
A true 2-channel audiometer (commonly referred to as a ‘full’ or ‘independent’ 2-channel audiometer) has two separate audiometry channels. These provide extra flexibility in audiological testing.
This allows the channels to be used for all test types including masking, which can be routed to either ear, allowing the user to play any signal.
It also has some deeper applications so the user can further investigate any identified hearing loss. Some examples of this deeper testing include:
- Identification of Cochlear Dead Regions
- CAPD (Central Auditory Processing Disorder) evaluation
- Advanced paediatric testing
- Cochlear implant assessments
- Examples of a full 2-channel audiometer are the GSI Audiostar Pro and Interacoustics AC40.
Which audiometer should you choose?
The type of audiometer depends on your needs; you should understand why you are testing and how you will use the output data. Consider other variables here too, for example:
Cost: Typically, a full 2-channel audiometer is more expensive, as in essence, it’s two full audiometers. This will also increase the annual calibration cost, so budget could be a limiting factor.
Complexity: A full 2-channel audiometer can be more complex to operate than a 1.5-channel audiometer.
Additional function: Finally, full 2-channel audiometers are often supplied with additional tests. For example, integrated speech materials, high-frequency audiometry, ABLB, Tone Decay and SISI special tests.
Industry-leading audiometers
Our Model 270+ and Model 270 provide useful examples of the channel configurations discussed in this article. The Model 270+ is a 1.5-channel audiometer. It supports core audiometry tasks. These include tone audiometry with masking, speech audiometry, free-field testing, and hearing aid dispensing.
The Model 270 is a 2-channel audiometer. It offers two independent channels for users needing more flexibility in test setup and signal routing.
We designed both models for professional audiometry, and they support mobile or fixed testing based on service needs.
For more information, please visit the Model 270+ and Model 270 web pages. You can also contact our customer support team on +44 (0)1698 208216 or by email.
