Recent content by QAMatt

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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    Take a look at delta pick and place machines. If the thing you are moving is very light, the delta machines are unbelievable simple and they scale easily to very large sizes. Every axis is identical. There are a lot of hobbyists going this route for large 3D printers and so there's a fair bit of...
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    Hi @Dave Zan MEMS are all omni. Invensense has a plot in their beamforming document (see fig 2 in the link below). The final mechanics has a much larger impact on the pattern, of course > The TDK in your second link is low noise but much worse frequency response compared to the AD devices...
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    Hi Dave, these impressive noise levels have been pretty common now for years in MEMS mics. Link 1 is digital TDM MEMS mic with 88 dB DR and 65 dB SNR, noise floor of -91 dB FS (20K bw A weighting) and AOP of 117 dB (10% THD). Link 2 is an analog MEMS mic with 105 dB DR (!!!) and 67 dB SNR...
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    No, they can be quite good and they have to be because Amazon et al are trying trying to do speech recognition from across the room. The noise floor on modern MEMS is around 30 dBA or -105 dBV. And if you are testing at 90 to 100 dBSPL, there should be plenty of SNR.
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    Does the math require only two radii are used? Or could the system still be solved if you had a point cloud of measurements, each at a different radius?
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    Hi Hayabusa, yes, there's a word clock to ensure that all mics start sampling at the same instant. In that mode you need to inhale the 64 channels of mic data simultaneously (64 data bits). But that's no problem for an FPGA. The folks doing mic arrays/beamforming/etc have driven the requirements...
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    DIY 3D Speaker Scanner - the Mathematics and Everything Else

    NTK this is impressive what you've published here. You might consider a semicircle of MEMS mics to eliminate the need for a vertical axis and mic positioning axis (if needed). What has happened in the last 5-7 years around digital MEMS mics is nothing short of amazing, IMO. The demand from...
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    Review and Measurements of QuantAsylum QA401 Audio Analyzer

    Hi Dana, with the QA401 app (written in C#), the API interface is DotNet remoting. It's really easy if you are writing in managed C++, C# or VB. But if you are writing in a language not inside the MSFT "managed" languages bubble, then it's not so easy. Now, LabView has the ability to load a...
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    Review and Measurements of QuantAsylum QA401 Audio Analyzer

    Yes, true, but for better or worse that ship has sailed long ago. The days of a menu item for each settings have given way into grouped sea of controls, with mouse wheel playing a big role in selection and actuation. Take a look at the video below on how scroll wheels get used on ProTools. This...
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    Review and Measurements of QuantAsylum QA401 Audio Analyzer

    >> Hi Matt. Of course, just ask. Awesome and thanks! Some notes/observations from various comments in the thread: > I am not a fan...The rotary controls for example show no values. Yes, agree it could be better. But it's not without precedent as this is true for modern desktop scopes too...
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    Review and Measurements of QuantAsylum QA401 Audio Analyzer

    Hi @Amir, thanks for the analysis! I'm scratching my head a bit on the measurement with -60 dBr (relative to 2V) because that noise floor seems lower than if input was shorted. But I can report back in 24-48 hours. Is there a chance you could make another measurement if I had a clear request...
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    Audibility thresholds of amp and DAC measurements

    Yes, agree, the ability to warp the spectrum would be very useful too. I just posted a new thread in case anyone wants to try and report their results. https://www.audiosciencereview.com/forum/index.php?threads/qa_abx-test-results.8210/#post-204202
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    QA_ABX Test Results

    This is a continuation of the post here. I hope some others can give a try and share results here as I think it's very important to find those that can demonstrate unique skill in this area. I'm using source material from LessLoss--the 24-bit/96k version of Mephisto Waltz Excerpt #1. You might...
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    Audibility thresholds of amp and DAC measurements

    Agree. There is a tool I helped worked on a few years ago located here. The tool allows you to start with a reference wav file of your choice, and then it will introduce different types of distortion on-the-fly (crossover, bit depth, amplitude, clipping, TANH). You can set the intensity of each...
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    Measuring RME ADI-2 Pro with QuantAsylum QA401

    Looks like it went out on April 19. Amir has explained he has a lot of stuff in the queue, which I completely understand.
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