I think this was a sarcastic comment. Obviously "reproducing the ultrasonics" don't actually matter for music reproduction....
"Reproducing the ultrasonics" here is a sarcastic reference to any sampling rate higher than 24 kHz (it actually backs back well before digital music). Audiophiles often prefer it because it's claimed that it has a wider frequency response, a lower quantization noise by oversampling, increased transparency after recording and remixing, while critics believe it's a point of diminishing return, and increases the odds of unwanted distortion that actually decreases the fidelity.
His point is that once oversampling and filtering is done in hardware, the final output only needs to be encoded in a low sampling rate for its benefits, and all high-quality DAC and ADC already oversample the signal under the hood. Using 192 kHz for its output or music distribution is unnecessary, and only introduces drawbacks like additional IMD and wasted space.
What makes you think I am unfamiliar with the background?
Was it the polite way I pointed out that you had clearly missed the sarcasm?
Either way, the hostility is unnecessary.
> the polite way I pointed out that you had clearly missed the sarcasm?
That wording makes your comment just as hostile as theirs. If that's the intent you had in your first comment, well, you went first. Not much room to complain about low-level tit-for-tat hostility at that point.
But I think tone on the internet is difficult to read.
And I had no negative intent in noting the sarcasm. I didn't think the replier realised it, and I'm still not convinced they do.
- Christopher "Monty" Montgomery, the original author of the Ogg codec, founder of the Xiph.org Foundation, a real audio engineer.
It was to scare away the stone marter family that had made themselves a home under my parents' roof tiles. They are a protected animal where I live, so you can't just do anything to get rid of them. But they also tend to chew on cables in your car (they really do), making them dangerous. Also make a LOT of noise when they go hunting at night.
Looking up various ways to get rid of these animals (apparently they also really dislike the smell of toilet fresheners, which you can place under your car hood or something), I found an ultrasound device but it was kinda expensive for single use.
So I generated a bunch of high frequency tones, to make it extra annoying I had it do random(10,20) seconds of beep, then random(10,20) seconds of silence.
I burned this to a CD, made three tracks at 15kHz, 17kHz and 19kHz. I didn't go higher because I had no way to find out if the speakers would be able to reproduce that tone :) I could clearly hear 15k, and my parents a little. I could nearly hear 17k, and my parents swore they heard nothing. Neither of us could hear the 19k, even at the loudest volume.
Since I don't live there, we decided to put the 17k track on repeat, at max volume, because at least we knew it made a sound (that I could barely hear). The CD player was placed next to an open window close to the nest.
That very night, the stone marter family got up and left. We assumed they probably just moved a few houses over, or something. However ...
Just to be sure they wouldn't return, my parents left the CD player on repeat for an entire week. After that week when my dad turned off the CD, five minutes later, he walked into the garden ...
"Hey, the birds are back!"
(... and to think there's a popular route close to their house for people walking their dogs ...)
So yeah, that definitely worked. It's just not very specific :-P
Drove the dogs a little crazy until I found it.
FWIW, I have a cat myself, and I'm not the kind of person to annoy animals on purpose.
I dunno how hard they are to build (that guy was pretty skilled), but I think you can also just buy these devices ready made. Probably called "bat detectors" or something.