Abstract: We describe a straightforward method/device that provides the “ideal” compensation to small micro-speaker acoustic transducers, such as those in current large-scale use in earbud headphones. This compensation results in an audio transducer that provides an output that precisely reproduces the input sound quality to the listener. The transducer thus has a “flat” reproduction for input sound; i.e. the reproduction is linear and independent of the sound frequency over a designated frequency range such as 20 Hz to 20,000 Hz. Applications for music appreciation and for speech comprehension enhancement for mobile phone communications are discussed.

Abstract: When an in-ear earbud is inserted into the ear canal, a front side sealed enclosure is created. The enclosure volume is sealed at the near end by the in-ear earbud and at the far end by the eardrum. The air trapped in the ear canal provides a stiff reactive volume that is comparable to the rear sealed enclosure volume provided by the earbud housing. An in-ear earbud simulator that closely replicates the ear canal volume and shape permits real-use measurements of the in-ear earbud frequency response. Such measurements lead to a transfer function that provides a frequency near flat frequency response. The transfer function is implemented with first order high pass and first order low pass circuits, either analog or digital in their embodiment. Additionally use of the approach for speech comprehension enhancement for cell phone conversations is implemented.

Abstract: A small hand-held optical scanning device for the accurate and precise scanning of lines of text characters is described. The scanner does not require any mechanical means of providing tachometer-like or encoder-like scanning signals in order to establish an accurate reproduction of the scanned text. An auxiliary single element detector samples the scanned text at an advanced (retarded) position relative to the main one dimensional scanner of the device. This advanced detector sensor, together with appropriate and disclosed software algorithms, permits the accurate correction of baseline imperfections as well as corrections for scan-speed non-uniformities and basic scan-speed errors. The processed scanner output is sufficiently faithful to the scanned text that optical character recognition (OCR) software can precisely interpret the scanned images and subsequently provide an accurate ASCII representation of the scanned text.