My father’s in his mid 70s and his hearing isn’t very good in the frequency range that would be useful for finding his vacuum leaks.

I was thinking about setting him up with a directional microphone and a pitch-shifter app to bring environmental sounds down a couple octaves so he can hear them. There are tons of Android/iPhone apps that will pitch-shift in post, but none of the trial/freemium ones seem to work on a realtime monitor stream, especially on an external USB (UAC) microphone. I don’t want to start buying dozens of apps just to try them.

Any app suggestions or other ideas for him?

  • morbidcactus
    4·
    11 days ago

    If I recall, doesn’t a leak need to be pretty substantial to detect in the audible frequency range?

    I’ve trialed and pushed usage of ultrasonic tools for this when I worked in maintenance engineering, some of my colleagues used then quite extensively and were able to justify the costs after the found a single tool air leak. Were also pretty interesting for bearing inspection, could pick up on damage far earlier than it’d be detectable with vibe or acoustic tools (certainly far earlier than thermal), they enabled some interesting lubrication practices too, aiming to prevent over-lubrication.

    I found this USB ultrasound microphone that’s supposed to be compatible with any recording application. My experience, just a UT microphone was more than enough to pick up leaks, it’s very directional and presumably you’re going to be fairly close to the source, it is expensive at €250, might be something to keep in mind.

    I like the idea that was brought up to maybe try a frequency analyser first? Spectroid on android or Sound Spectrum Analysis were recommend by Voron Deaign for 3D printer tuning purposes (belt tension, though I use a printed tensiometer for that these days). Only thing I can think of is yeah, will a vacuum leak be detectable in the audible frequency ranges? Probably worth a try regardless.

    • dylanjusticeOPEnglish
      2·
      11 days ago

      Thanks! Found a couple of much cheaper ultrasonic detectors that claim to do this, so we’ll try those (and the spectrum analyzer) first. The usb mic looks great if those don’t pan out!

      • morbidcactus
        1·
        10 days ago

        I’d be totally interested to see how those work, what sensors did you grab?

        • dylanjusticeOPEnglish
          1·
          2 days ago

          We bought this AllSun adapter . It was able to confirm some smaller dropline leaks, but it missed more than it found. It was completely useless at finding the larger leaks (mostly in saddles and 3/4" tees) that seem to be the bulk of our problem.

          So I’m pushing him to try the hearing aid apps – this one is expensive, but seems to have a good combination of EQ and pitch shifting that may make it possible for him.