Dan Lopez Dan Lopez Ben Rohner Ben Rohner Erin Loutzenhiser Erin Loutzenhiser

Directionally Adaptive Microphone For use in classrooms, conference rooms, or anywhere else needing a multidirectional microphone. For use in classrooms, conference rooms, or anywhere else needing a multidirectional microphone. Uses digital signal processing (DSP) and custom algorithms to “follow” conversations taking place around it. Uses digital signal processing (DSP) and custom algorithms to “follow” conversations taking place around it.

Directionally Adaptive Microphone Pod shaped design – 9” diameter Pod shaped design – 9” diameter Uses 8 directional microphones Uses 8 directional microphones Active microphone(s) are determined based on Sound Pressure Level (SPL) detected at each microphone. Active microphone(s) are determined based on Sound Pressure Level (SPL) detected at each microphone. Microphone threshold settings Microphone threshold settings On/Off and Mute functions On/Off and Mute functions Ceiling mount or tabletop Ceiling mount or tabletop

Directionally Adaptive Microphone Two segments of the system were modeled: Two segments of the system were modeled: Microphone - DSP Algorithms and decision making process Microphone - DSP Algorithms and decision making process Environment - Room environment and sound interface with system Environment - Room environment and sound interface with system

Microphone Model Input Power Analysis Input Power Analysis Calculate average power of 50 ms block of data using the mean of the squares Calculate average power of 50 ms block of data using the mean of the squares Stored separately from audio data (Original data is retained) Stored separately from audio data (Original data is retained) Threshold Comparison Threshold Comparison Compare average power calculated to a set threshold level for each microphone Compare average power calculated to a set threshold level for each microphone If power is less then threshold, that input is considered zero for processing purposes If power is less then threshold, that input is considered zero for processing purposes

Microphone Model Decision Making Process Decision Making Process For each 50 ms block all 8 average powers are compared and the two greatest are passed on. For each 50 ms block all 8 average powers are compared and the two greatest are passed on. Upon initialization microphones 1 and 2 are selected as outputs Upon initialization microphones 1 and 2 are selected as outputs A microphone must be greater than the current selected microphones for at least 200 ms before a switch occurs A microphone must be greater than the current selected microphones for at least 200 ms before a switch occurs Prevents rapid switching Prevents rapid switching

Microphone Model Reconstruction Reconstruction The selected microphones and sound source are used to reconstruct the output The selected microphones and sound source are used to reconstruct the output Data is outputted as standard audio Data is outputted as standard audio

Microphone Model Demonstration

Sound Attenuation The sound attenuation due to distance was modeled as the inverse of the distance The sound attenuation due to distance was modeled as the inverse of the distance ATTN=1/R ATTN=1/R Environment Model

Microphone Coverage Microphones arrayed at 45 degree intervals Microphones arrayed at 45 degree intervals Each microphone has a coverage range of 48 degrees. Each microphone has a coverage range of 48 degrees. Adjacent microphone coverage zones intersect at 5 feet from the DAM-360 Adjacent microphone coverage zones intersect at 5 feet from the DAM-360 Environment Model

Test area is a room 20’x20’ with the DAM- 360 at the center with data points at 1” intervals Test area is a room 20’x20’ with the DAM- 360 at the center with data points at 1” intervals Overall environment model created by combining the sound attenuation and the microphone coverage Overall environment model created by combining the sound attenuation and the microphone coverage

System Evaluation

Demonstrations Microphone and Environment Models Microphone and Environment Models User Interface Model User Interface Model

Potential Improvements Final audio processing Final audio processing File and data format, etc. File and data format, etc. Individual threshold levels Individual threshold levels Input filtering Input filtering Real-time implementation Real-time implementation

Potential Improvements

Future Work Create Prototype Create Prototype Implement Mute Button, On/Off Button, and LED indicators Implement Mute Button, On/Off Button, and LED indicators Market Analysis Market Analysis Determine potential market for device Determine potential market for device