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Noise File Comparison Tool

7/22/2021

 
Whether you’re in a teleconference, a live music setting, or simply working in an office, noise and room reverberation time can affect your ability to pleasurably listen.  With our new Noise Files Comparison Tool, you can hear and easily compare different kinds of noise to aid in self diagnosing issues quickly and efficiently.  For example, you can toggle between 60Hz, Bluetooth, GSM, and Wi-Fi noise interferences to help find the source of unwanted sounds.  Also included are different types of broadband and background noise such as pink noise, white noise, city traffic, and a crowded pub.
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Additionally, recordings of the in-house Head and Torso Simulator (HATS) playing back an IEEE standard speech file were taken in an anechoic chamber, an acoustically treated room, and a highly reverberant non-acoustically treated room. These can be compared to highlight the impact partial and full acoustic treatment has on speech intelligibility.  

We can also use this tool to create custom recordings of your product in different noise conditions, tuning configurations, or other impairments- for subjective evaluation without a trip to our lab. For dB-accurate reproduction we ship you a DAC and Reference Headphones with Comparison Tool files corrected for both the headphone response and binaural HATS Head Related Transfer Function (HRTF).
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By: Shannon McConnell

Voice Coil: March 2021 Article

3/1/2021

 
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Indy Acoustic Research collaborated with Listen, Inc. to bring the data behind the article "How to Measure Free-Field Speaker Response without an Anechoic Chamber" featured in the March 2021 Voice Coil article, linked below!

The hybrid splice method of loudspeaker frequency response measurement compares well with an anechoic chamber for a single loudspeaker if the splice frequency can be determined. However, complex devices require the greater flexibility in setup conditions and off-angle measurements afforded by a full chamber. 
article_vc_mar2021_simulated_free_field.pdf
File Size: 8919 kb
File Type: pdf
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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!

3D Printing in-House

3/21/2018

 
To speed iterative prototyping and fixture creation for some assemblies and housings, IAR has brought reliable and low-cost FDM prototyping in-house. Common items we print include speaker baffle adapters, customer housing mockups for probe microphone measurements, or other fixtures to support device assembly or measurements. Maximum print size on this device is approximately 9 x 8 x 8 inches. High-resolution SLA and smaller assemblies will continue to be sourced from a handful of Indianapolis-based prototyping shops.
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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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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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