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1answer
24 views

Looking for a way to monitor raw microphone digital output?

This is sort of a cross between a data processing and Physics question, but I would be grateful if anyone here could help me. My objective is to calculate the sound pressure level (in dB) of a sound ...
0
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1answer
72 views

I have a pressure signal and want to do SPL analysis on it

Signal I have an acoustic signal from a Ffowcs Williams Hawkings CFD analysis and would like to convert it to the frequency domain and see the SPL and OASPL. I know I need to use fft() but I am ...
3
votes
1answer
67 views

Acoustic room simulation - Craven's hypothesis

I'm reading Udo Zölzer's "Digital Audio Signal Processing" and there's a piece about acoustic room simulation. This question will be more about maths and acoustics, but I assume anybody who does DSP ...
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0answers
46 views

White noise sound vs harmonic sound reverb

I use a microphone array to localise a sound source in a small lecture theatre. I tested it with white noise and a bird noise source. I found out that the white noise source give very good results. ...
3
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1answer
86 views

Acoustical Design considerations for Active Noise Cancellation Project for Air vent

I am working on ''Active noise cancellation for air vent'' project. I am using NI myRIO1900, Audio Technica ATR 3350 omni directional microphones and Tevion Loudspeakers. I have done the programming ...
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2answers
144 views

How many samples per cycle(time period) is actually enough to reproduce the sine wave sound properly?

I have been working on Active Noise Cancellation in real time for Air vent in kitchen. Initially for the demonstration purpose, I am using sinusoidal sound ( 40k Hz Fs,1000 samples, 2 kHz frequency, 1 ...
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2answers
71 views

How does mic combined with loudspeaker work?

There is variety of loudspeakers on the market that have built-in microphone so that they can produce sound and perceive it at the same time (and do it surprisingly well). How they managed to ...
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0answers
10 views

Acoustic characteristics of thoracic diaphragm

I am looking for any kind of information about the acoustic characteristics of the thoracic diaphragm. In particular, I'm looking for characteristics which will allow to differentiate it from other ...
3
votes
1answer
47 views

Proof from wave equation of upper limit of active noise cancellation

Anybody know of a proof of the hard upper frequency limit of active noise cancellation using the ear canal volume as a boundary condition to solve for the upper frequency limit? I keep on encountering ...
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0answers
60 views

Reverberation time reliability evaluation (ISO 3382-2)

I am processing reverberation times using the reverse-integration method described in ISO 3382-2 and I am a bit puzzled by the conditions sfor checking the result reliability indicator. One of them ...
1
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1answer
108 views

Normalize Fourier Transform For Video Game

I am in the process of developing a video game where I would like to sync a character's mouth with an audio clip of their speech that is playing. I found this great website that shows the profiles of ...
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0answers
77 views

MATLAB band-stop filter design for room reverberation?

I took acoustic measurements of a room using sine swept method, and I also used Pioneer sc-37 to obtain more accurate data. I used RoomEQ wizard software and measured the impulse response of the room,...
0
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2answers
141 views

How to take acoustic measurements of a clasroom

I'm an electrical engineering major and I have a question regarding a project I'm working on. I'm supposed to design 3 band-stop filters on MATLAB for echo cancellation/suppression. My problem is ...
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1answer
307 views

What is the best method for measuring of room reverberation time?

I want to measure a reverberation time in the room. What is a best way to do that? What kind of signal should be used? I know about balloon and pink noise, but are there any better methods?
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2answers
73 views

separate static echos from acoustic signal (ICA?)

Iam using acoustic waves to measure the thickness of material. My problem is that the acoustical lense produces static echos in the signal. I try to seperate both because there is a short interference ...
0
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2answers
40 views

Acoustic record and store devices

I am working on a project involving analysis of bird sounds and I want to record these sounds in slightly remote locations. It is enough if the device can only record and store them (maybe in an SD ...
0
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2answers
281 views

Convolving Room Impulse Response with a Wav File (python)

I have written the following code which is supposed to put echo over an available sound file. Unfortunately the output is a very noisy result which I don't exactly understand. Can anybody help me with ...
2
votes
1answer
219 views

How is LMS/FXLMS noise cancelling different than simple polarity inversion?

Consider a noise-cancelling headphone: If I have a noise signal from the outside world, mic it, flip the polarity by multiplying by -1 (with an op-amp or digitally), delay by the appropriate amount, ...
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2answers
3k views

Confusion regarding reverberation time (RT60) calculation

I have some confusions regarding reverberation time (RT60). I need to calculate reverberation time from a given power envelope. This is what I get. As you might see the line is curved close to zero (...
3
votes
1answer
113 views

Underwater Acoustic Positioning

I have to develop an underwater positioning system which has to determine the position of a ROV. Four buoys will be placed on each corner of a swimming pool. Each one of these buoys will be equipped ...
0
votes
1answer
41 views

what is standard acoustic volume

In Audio Experts book, it's given as Sound pressure meters must be calibrated at factory to a standard acoustic volume. So what doth this ...
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0answers
21 views

Diference between Specific,perceived and perceptual Loudness

i came across many terms describing loudness ! I understood perceived loudness which is what the user perceived and is related to the user. What is specific loudness and perceptual loudness? ...
3
votes
2answers
76 views

Dealing with echoes / dead-spots in digital transmissions

I'm looking at communicating digital data through the air as soundwaves. To illustrate the problem, I generate a 10-cycle 2kHz wave, play it out through my MacBook's speakers and pick it up on my ...
2
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2answers
86 views

is there a second order approximation to perceived loudness

Quoted from this As a first order approximation it takes ten times the energy to double the perceived loudness So is there a 2nd order approximation. If so then how much change in RMS value ...
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0answers
40 views

Echo detection for localization

I was reading about active sonar and couldnt quite understand how the echos are recognized. My doubt is, when the sound signal is reflected back, it is greatly attenuated and distorted due to many ...
3
votes
1answer
888 views

Acoustic feedback detection algorithm

I am woking on an sound processing application where I have limited processing resources. I need to be able to detect acoustic feedback and then signal that such an event occurred. I am not concerned ...
3
votes
1answer
124 views

Estimating harmonic loudness

I'm working with data that looks something like this: ...
6
votes
1answer
260 views

How do Phons relate to loudness?

Let's say I have the very same signal stored in 2 .wav files. And lets say I process each file using a function, and it is established that one file is 20 phons ...
5
votes
1answer
691 views

What are reasonable levels for the ERLE (Echo Return Loss Enhancement) in acoustic echo cancellation?

I am working on acoustic echo cancellation which has a double talk detector. During the single talk, the ERLE (Echo Return Loss Enhancement) exceeds 100dB and during double talk around 20dB to 40 dB. ...