Wayne's World

A previous post described the Doppler effect in a simplified manner as it relates to movement and sound waves.  This post expands on this somewhat by providing a series of Doppler effect animated images to clarify the role of a moving object and its impact on the sound.  It has been said that a picture is worth a thousand words. 

Does motion affect sound?   If you pay attention, your ears will most likely tell you the answer is “yes,” specifically in frequency.  This effect is readily noticed with respect to the sound from fast-moving vehicles.  When vehicles pass close to you, you will hear its sound suddenly change in pitch (frequency) just at the moment it passes by.  This

Last week’s post chronicled the story of Harley-Davidson, the motorcycle manufacturer, attempting to get a federal trademark on what many call the unique sound of a Harley (motorcycle).  After years and tens of thousands of dollars fighting comments from other motorcycle companies, and no end in sight to the litigation, Harley voluntarily withdrew their sound branding trademark application. This HHTM

Sometimes late at night, accountant Laura Weiner thunders through the New River Tunnel in Fort Lauderdale, revving her Harley’s engine.  ”I love that sound,” she says1.  It is what many call the the HOG’s sweet sound.  But, this sound is not a squeal, and this HOG is not for eating.    And, evidently, many other motorcycle riders like the sound. 

Terminology associated with ear impression material is sometimes confusing to those who take ear impressions on a routine basis.  This post continues the discussion on ear impression terms from a previous post. Compression Set   This is the amount of permanent deformation resulting when a material is compressed to a specific deformation for a specified time and temperature.  This test

Ear impression material has been developed to provide certain characteristics to enable it to provide as accurate a representation of the concha and/or ear canal as possible. This means that it should flow properly, provide an accurate image of what it comes in contact with, set up properly without distortion, remove without distortion or breakage, maintain its shape during storing

By James Curran          Recent generations of audiologists may have heard Earl Harford’s name from their teachers or run across one of his many publications and writings during their student years. But only those of us who were there from the early days really know who he was and what he meant to our profession. Earl Harford

Logic would suggest that with the advantages of silicone ear impression material, that the transition from ethyl methacrylate to silicone would have occurred fairly rapidly. Not so, as ear impression history shows. In essence, the 1970s was the main transition period, but it started in the 1960s, and continued well into the mid 2000s.   1970s – A Period in

The desire to use the ear impression as the final earmold was an early objective of some earmold impression providers. For hearing aid dispensers, to be able to provide instant earmolds from impressions would certainly circumvent many of the problems they encountered with delays in delivery, remakes, distant service calls, cost, etc.      Early instant earmolds from impression materials fell

Ear impression material is basically a compound (substance formed from two or more elements) with polymer, or a blend of polymers, as the fundamental component in determining the impression material properties.  Affecting the polymer makeup are the type of molecular forces that are applied.  Monomers (one part) are the building blocks that when bonded together (Figure 1), create the more