I was just doing research and landed on this exact page last night! I was wondering if anyone knows how someone could mic a room and record audio from only a specific area. For my use case I want to record a couch so I can watch TV with my friends online and remove their speech + show noise from the audio. Setting up some array of mics and using them for beam steering would probably work but there's not a lot of examples I could find on GitHub with code that works in real time.
Phased Array Microphone (2023)
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Re: Phased Array Microphone (2023)
#12I once did a project to do multilateration of bats (the flying mammal) using an array of 4 microphones arranged in a big Y shape on the ground. Using the time difference of arrival at the four microphones, we could find the positions of each bat that flew over the array, as well as identify the species. It was used for an environmental study to determine the impact of installing wind turbines. Fun times.
I would love to do something like that to track the bats in my garden, how feasible would it be for an amateur to do as a personal project?
Any good references on where to start.
Re: Phased Array Microphone (2023)
#13I wonder how well this would work with laser microphones on a pane of glass. Can you infer keystrokes with near infrared laser? That is, can you identify the heatmap of keystroke events to infer which keyboard they're using, then replay the tape to identify the strings of characters being typed? Can you localize the turning of pages with UV?
Re: Phased Array Microphone (2023)
#14What is the most practical application for this technology? Could you use it to pinpoint sounds coming from a car like a squeak?
I've always wanted this for videoconferencing room. A microphone array around the screen should be able to dynamically focus on the active talkers and cancel out background noise and echos to get much better sound quality that the muddy crap we usually get.
If there were a speaker array around the screens too, you might be able to localize the audio for each person so that it seems like the sound is coming from where their head is on the screen.
Re: Phased Array Microphone (2023)
#15"As part of the calibration, the speed of sound is also a parameter which is optimized to obtain the best model of the system, which allows this whole procedure to act as a ridiculously overengineered thermometer."
Reminds me of the electronics adage: "all sensors are temperature sensors, some measure other things as well."
Re: Phased Array Microphone (2023)
#16I was just doing research and landed on this exact page last night! I was wondering if anyone knows how someone could mic a room and record audio from only a specific area. For my use case I want to record a couch so I can watch TV with my friends online and remove their speech + show noise from the audio. Setting up some array of mics and using them for beam steering would probably work but there's not a lot of exam…
From the article "The simplest method of beamforming is delay-and-sum (DAS)". Measure distance from a point (couch) to each microphone, delay the signal in time domain by the time the sound takes to travel from point (couch) to microphone, and add up the signals. Pretty trivial. Basically you want the microphones receive the couch signal at the same time, even though they are different distances away.
Make sure there is enough variation in microphone distances for this method to be effective.
Re: Phased Array Microphone (2023)
#17I once did a project to do multilateration of bats (the flying mammal) using an array of 4 microphones arranged in a big Y shape on the ground. Using the time difference of arrival at the four microphones, we could find the positions of each bat that flew over the array, as well as identify the species. It was used for an environmental study to determine the impact of installing wind turbines. Fun times.
Honestly, that sounds like amazing work. I wish I could afford to get out of enterprise software engineering and just do academic software development like that.
Re: Phased Array Microphone (2023)
#18I once did a project to do multilateration of bats (the flying mammal) using an array of 4 microphones arranged in a big Y shape on the ground. Using the time difference of arrival at the four microphones, we could find the positions of each bat that flew over the array, as well as identify the species. It was used for an environmental study to determine the impact of installing wind turbines. Fun times.
What were the results of your study? I’ve heard that bat lungs are so sensitive that when they fly across the pressure differential of large turbines their capillaries basically explode
Re: Phased Array Microphone (2023)
#19I was just doing research and landed on this exact page last night! I was wondering if anyone knows how someone could mic a room and record audio from only a specific area. For my use case I want to record a couch so I can watch TV with my friends online and remove their speech + show noise from the audio. Setting up some array of mics and using them for beam steering would probably work but there's not a lot of exam…
Loud show noise and your online friends' nearby audio is going to be reflected around the room as well as off of your bodies.
What you want isn't microphone or beamforming tech, it's echo cancellation the same as every videoconferencing software uses.
You just need to feed the show audio and friend audio in, and apply echo cancellation to each.
Re: Phased Array Microphone (2023)
#20What is the most practical application for this technology? Could you use it to pinpoint sounds coming from a car like a squeak?
I've always wanted this for videoconferencing room. A microphone array around the screen should be able to dynamically focus on the active talkers and cancel out background noise and echos to get much better sound quality that the muddy crap we usually get. If there were a speaker array around the screens too, you might be able to localize the audio for each person so that it seems like the sound is coming from where…
Shure sells a variety of array microphones (and the software) that handles similar things. I've never used one, but heh.