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The more reliable guitar tuners do something like this. You clip them on the neck, and they detect vibrations in the wood rather than from sound in the air.
oddly, this is how I learned to tune my guitar. I'm pretty tone deaf, but can feel the difference between the reference string and the string I'm trying to tune through the guitar.
Thanks for sharing.
This sounds neat, but I think I owned a tuner for about 6 weeks before I could do it by ear... EADGBe isn't that hard.
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oddly, this is how I learned to tune my guitar. I'm pretty tone deaf, but can feel the difference between the reference string and the string I'm trying to tune through the guitar.
This is fascinating. Thanks for sharing.
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The CIA…plug a set of regular headphones into a microphone jack, open a recording application and speak into the headphone speaker, you don’t need a 3 letter agency for that physics open secret.
I am crap with physics but was going to say I think the last 50+ years of speaker development has been about making them less a microphone than they inherently are.
This has some very interesting privacy and security risks. If the tech can do more complex frequency analysis, then couldn't it essentially be used as a microphone for a device that doesn't need permission.
It's a pretty well-known exploit that the CIA is capable of turning a lot of electronics with speakers into microphones. I imagine there is an entire classified backlog of things they can turn into microphones without the target's knowledge.
This has some very interesting privacy and security risks. If the tech can do more complex frequency analysis, then couldn't it essentially be used as a microphone for a device that doesn't need permission.
It's a pretty well-known exploit that the CIA is capable of turning a lot of electronics with speakers into microphones. I imagine there is an entire classified backlog of things they can turn into microphones without the target's knowledge.
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The CIA…plug a set of regular headphones into a microphone jack, open a recording application and speak into the headphone speaker, you don’t need a 3 letter agency for that physics open secret.
I am crap with physics but was going to say I think the last 50+ years of speaker development has been about making them less a microphone than they inherently are.
Dynamic loudspeakers and dynamic microphones are the same thing. They always have been the same.
They've got the knobs for the design variables turned in different directions, but they're still the same.
They even have the same frequency response whether they're being used as speakers or microphones at the moment.
Which brings up a valid way to measure the response of a microphone's design:
Use two of them. One as a speaker, and the other as a microphone. Play measurement-sounds out of one, and record the results on the other. Plot it out.
The deviations are magnified, but eliminating that magnification is just a math problem -- not an instrumentation problem. :)
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The accelerometers that protect the average hard drive are easily subverted for this purpose.
There is something better. The little sensor that maintains the distance between the spinning platter and the armature is sensitive enough to be a reasonable microphone. But it is inside a heavy metal box (the HDD) so you do need to shout at it. https://physics.aps.org/articles/v12/24 >> They tapped into the feedback system that helps control the position of the read head above the magnetic disk. When the head is buf…
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Don't have a handle on it, unfortunately. But the algorithm is in here: https://github.com/tautme/phone-sensors/blob/main/guitar-tun... . Esp. lines 221–257 and 373–417.
The code mentions "autocorrelation" method: this is a method where you multiply the signal with delayed version of itself: result = sum(x[i] * x[i - delay] for i in some range). You vary the "delay" and pick the value that maximizes the result. This is based on the idea, that the sequential periods of the signal should be similar to each other. Not a very good method, prone to octave errors (showing pitch one octave…
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heh, a subacoustic G#?
I think the tuner is off by an octave - it has a lot of harmonics and sounded like a G on a bass guitar.
Unless it didn't function like a string at all, then the harmonics would be all wrong.