Good Question: What is the Difference Between 1.5 and 2 Channel Audiometers?

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by Laura Prigge, AuD

As an audiologist for GSI, I often get the question about the differences between the AudioStar Pro™ and Pello™ audiometers. Since the Pello was released in 2016, GSI has been very clear that it is a 1.5 channel mid-level audiometer and that the AudioStar Pro is our 2 channel clinical audiometer. They look very similar (you can definitely tell they’re related) and “audiometry is audiometry”. So, what’s the real difference between the instruments besides the price? This blog post will unpack that question.

AudioStar Pro and Pello audiometers from Grason-Stadler

When GSI says “2 channel instrument”, it is referring to an audiometer that is able to perform all functions on both channels at the same time. The fancy way to say that is that a 2 channel clinical audiometer has two identical and independent channels. GSI’s 2 channel audiometer is the AudioStar Pro. This is the replacement for a long legacy of clinical 2 channel instruments (GSI 61 and GSI 16). This is an important distinction for hearing healthcare providers to consider. With a 2 channel audiometer, you are able to use channel one to conduct speech audiometry and have a tone stimulus routed through channel two simultaneously. It is also possible to route stimuli from both channels into the same ear for seamless pediatric testing. Both channels can present and route stimuli to any ear and transducer that is available. 2 channel clinical instruments often include several special tests such as QuickSIN, BKB-SIN, and the TEN test. With its full routing flexibility, array of sound field options, and multiple transducer capabilities, a 2 channel audiometer is the answer for complete clinical testing of all age ranges.

When GSI says “1.5 channel instrument”, it is referring to an audiometer that has limited functionality in routing. Since there’s no fancy way to say that, it means that a 1.5 channel audiometer has one channel that is ALWAYS the stimulus and the other .5 channel is always the masking. Additionally, the .5 channel is always the opposite ear from channel 1 except for very specific use cases like the Stenger test. GSI’s mid-level 1.5 channel audiometer is the GSI Pello. A major distinction between 2 channel and 1.5 channel audiometers is that mid-level (1.5 channel) audiometers do not have all the bells and whistles of clinical instruments; however, it is often possible to add functionality through licenses and modules. The GSI Pello has 4 different license options that you can add at the time of purchase or at a later date if your testing needs evolve. The standard model of GSI Pello includes air conduction, bone conduction, and speech (recorded and live voice) testing capabilities. You can add high-frequency testing, QuickSIN, BKB-SIN, Special tests, the TEN test, or classic auditory tests with additional license add-ons.

You can learn more about the AudioStar Pro 2 channel audiometer here and more about the Pello 1.5 channel audiometer here. Additionally, you can see a side-by-side breakdown of the features of both audiometers below.

A comparison chart between the AudioStar Pro and Pello