Welcome to Cochlear Concepts, LLC.
Some of the links may not be active--my apology for this. Thank you for your interest in this site.
Eric L. Carmichel, owner, can be reached at

Our mailing address:

1534 N Dorsey Ln
Tempe, AZ 85281





The link below goes to our parent site.

ELC Audio Engineering (click on image)

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Welcome to Cochlear Concepts™ LLC -- Home of the Veridical* Reality System (VRS)
*Veridical synonyms include veracious, truthful, true, and honest.

Cochlear Concepts is developing a new cochlear implant (CI) processing strategy and active electrode array. Unlike conventional speech processors and passive electrodes, the active array opens new doorways for real-time processing. For the latest information, please see our FAQs page. Cochlear Concepts also develops controlled, real-world auditory environments with video for speech & hearing science researchers. In addition to speech material (IEEE sentences, etc.), our stimuli include stationary and dynamic targets along with naturally occurring reverberation. The external validity of investigations regarding cochlear implants, hearing aids, and hearing protection is further enhanced by the use of periphonic systems that utilize Ambisonics, High Order Ambisonics (HOA), Wave-Field Synthesis (WFS), or acoustic holography. For many applications, to include CI and hearing aid (HA) research, HOA is an appropriate technology because the sound field is reproduced correctly in the middle of the loudspeaker array (as opposed to WFS, where the error is spread around the whole area of reproduction). Our Ambisonic recordings were made in a variety of establishments, to include "quiet" restaurants and coffee cafés. Recordings of quieter establishments are useful for studying cochlear implant processor strategies because the judicial use of moderate background noise allows the researcher to maintain positive signal-to-noise ratios (e.g., + 10 dB) that accurately represent real-world scenarios. The recordings were made using a specially designed Ambisonic microphone to capture each sound sources' direction (in the horizontal and vertical directions!) as well as natural reverberation. The raw (A-format) recordings were 24 bit, 96 kS/s digital recordings. Many of the B-format files and multi-channel stimulus files have been dithered to 16 bit for portability.

Future postings on this site will include information on how Cochlear Concepts re-creates 3D listening in the laboratory--just as sounds exist in the real world. Interested parties are encouraged to read related articles from The Hearing Journal and Acta Acustica united with Acustica. It should be noted, however, that our Ambisonic surround system incorporates live recordings in addition to auralization techniques utilizing room impulse responses (RIRs). Cochlear Concepts will also provide information on the development of ergonomic participant interfaces utilizing embedded microcontrollers. The microprocessor-based interfaces are used to automate stimuli presentation and data acquisition for experiments performed in virtual listening environments. While this website is new, Cochlear Concepts will soon be adding links to our research, articles on Ambisonics (with permission from their respective authors and publishers), and the mathematics behind spherical harmonics. Note: Spherical harmonics should not be confused with the usual definition of "harmonics" that we often encounter while discussing sound or music. Spherical harmonics are, in a nutshell, the angular portion of a set of solutions to Laplace's equation, first introduced by Pierre Simon de Laplace (click here for Wikipedia link to spherical harmonics). Ambisonics was largely developed by the late Michael Gerzon (Professor of Mathematics, University of Oxford); it is mathematically based on spherical harmonics.

Above: The beginnings of Cochlear Concepts surround system: This photo was taken before various acoustic treatments -- a combination of diffusers and absorbers -- were put into place. The radius of the circular array of speakers is 1.4 meters. Below: Same speakers, same room, but in a semi-circular configuration (radius = 2 meters). Using the closely-spaced speaker arrangement shown below, it should be easy for listeners to localize to a sound emanating from a single loudspeaker-source location. The first research question to be answered is this: Using Ambisonics and live recordings, can polyhedra arrays consisting of only six or eight loudspeakers give the same sense (or accuracy) of sound-source direction, even when listeners move their heads, as when localizing to a speaker in the closely-spaced array shown below? Conventional, level-only panning among five or seven speakers in typical "surround" mixes doesn't permit such localization accuracy--this is especially true for sounds intended to originate from the extreme left or right sides or for sounds emanating from behind the listener.