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New Bruel & Kjaer 5128 added

1/3/2019

 
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The Bruel & Kjaer 5128 is the latest state-of-the-art Head and Torso Simulator (HATS) for acoustic measurements. IAR has recently added this new binaural HATS, allowing us to expand our test capabilities and setups.

This includes:
  • high-resolution headphones
  • handsfree devices
  • superwideband speakerphones.
  • ETSI 202-391-1 and ITU-T P.570 room calibrations
​ Please contact us if you need hi-resolution device measurements or setting up test rooms with simulated background noises!

Simulation of Microphone Arrays

3/19/2018

 
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 Many far-field voice devices employ beamforming microphone arrays to improve speech recognition and communication performance. However, often the simulation of the acoustic wave during DSP design only includes phase differences due to array spacing and neglects more complex geometry such as element porting, enclosures, tables or walls.  These objects cause diffraction and reflections of the incoming acoustic wave around the sensor can lead to errors in beamforming and direction-of-arrival algorithms. IAR can use Comsol Multiphysics or Lumped Element Simulation (depending upon the complexity of geometry, frequency range of interest and available time) to provide simulated complex acoustic pressure “vectors” to DSP designers to improve the performance of the array including geometric features, prior to any prototype production or PCB fabrication.

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Central Indiana AES Visits IAR

3/23/2017

 

Larry Marcus and Marc Reese

The Central Indiana Section of Acoustical Engineering Society (CI-AES) held its March meeting at Indy Acoustic Research LLC with approximately 20 members in attendance.

Humorously dubbed "now for something completely different" (echoing Monty Python), IAR demonstrated the world of embedded audio- where a "large, full-range" speaker is 40 or 50mm diameter. Participants observed testing of voice-controlled virtual assistants in the anechoic chamber, headphone testing in interfering noise in the sound booth and simulation examples of headphone design.
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Glenn explains details of acoustic testing on cloud-based virtual assistants.
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Method for displacement measurement to obtain T-S Parameters

IAR Turns ONE

4/4/2016

 
By: Marc Reese and Larry Marcus
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Indy Acoustic Research celebrates its first year! 

A lot of effort has gone this year into building our lab's capabilities to ensure we can support our customer's needs and timing. Below are some pictures of some of our activities in the past few months.
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Indy Acoustic Research now has the capability to measure speaker displacement directly though a non-contact laser.
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We're just baffled! An IEC-60268 spec baffle allows for testing speaker components up to 3" diameter.
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Simulation improvements have been made for leaky ear models (4195, shown), Transmission Line models of circular and rectangular tubes and radiation patterns of loudspeakers.
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Perceptual Objective Listening Quality Analysis (POLQA) testing on HATS in a customer-defined diffuse noise profile requires that SoundCheck, DAW and POLQA software are run simultaneously
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One of the annoyances in the venerable B&K 4128 HATS is that the chin clip for holding the mic splits due to the stress concentration from inserting the mic. A fuse clip costing less than a dollar is an economical fix with no measurable change to the acoustic field.

Bell Labs Indianapolis Anechoic Chamber History

11/17/2015

 
by: Larry Marcus

Built in 1984, the IAR Anechoic Chamber is like me: it’s old but it still works. It has a cutoff frequency of about 120Hz and is about 3 meters by 3.7 meters by 2.6 meters tip-to-tip.  Compare the photo here with the more recent one below in this blog series with the four intrepid IAR founders!

Significant products developed and studies conducted in our anechoic chamber include many IEEE and TIA standards contributions, the first gradient microphones with speakerphones, first extensive ISDN and VoIP testing, first mechanical-acoustical analysis of conference phones, etc., not to mention days upon days of other transducer development and product testing.
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Former Bell Labs colleague Rich Sachs stringing floor cables
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The wedges were white? Must have absorbed so much sound over the years that they've turned yellow!

Diffuse Field Booth

9/18/2015

 
The Diffuse Field Booth is a large audiometric booth and features 8 pro-audio surround speakers and one subwoofer. This setup is calibrated per IEEE 269 to accurately simulate a diffuse noise field, so it's perfect for testing the noise rejection of headset or handset microphones, or noise isolation of headphones (either passive or active noise-cancelling types).  
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HATS in the simulated surround field.
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