5 ms·
18-20khz is not really ultrasound. Many people can still hear this range, and it's very unpleasant when played (at least to me). For comparison, medical imagin
by lxe 1y ago
18-20khz is not really ultrasound. Many people can still hear this range, and it's very unpleasant when played (at least to me).
For comparison, medical imaging ultrasound is 2-20 MHz (that's MEGA hertz) I think,
- thfuran 1y agoYeah, 18 kHz isn't really ultrasound, but 50 kHz definitely is and nobody's hearing that. You definitely don't need to go up into the MHz range and can't if the goal is to use existing audio equipment.
- lxe 1y agoThey are using the 18-20Khz range though (https://halcy.de/blog/images/2025_06_27_fsk.png https://halcy.de/blog/images/2025_06_27_fsk.png)
- dylan604 1y agowould the stock equipment be able to produce MHz? consumer gear is targeted specifically at making sounds humans can hear. Since the 18-20kHz is within the 44.1-48kHz audio tends to playback, it makes since why it would be near-ultrasound frequencies. The headline specifically mentions without any special equipment
- lxe 1y agoTheoretically, yes! With 192kbps sample rantes you can probably render up to 96khz, but the limitation is the speaker and amp components all the way from your DAC to the main amp to the speaker.
- dylan604 1y agobitrate isn't really what we're concerned with here, though is it? if you use 96kHz sampling rate, you can reproduce 48kHz frequencies according to Nyquist. the bitrate would then be the sampling rate * bit depth * #channels. your 192kbps would potentially be the 96kHz * 2 channels, but you've left out the bit depth or using a 1-bit sample???
- madaxe_again 1y agoYou can also produce UHF sound with hardware other than the speaker. For instance, you can overdrive caps in various systems - most commonly LCD display drivers - and make them squeak in the audible or inaudible range. Can’t find much out there on the topic, but here’s a Reddit thread touching on it: https://www.reddit.com/r/InternetIsBeautiful/comments/2ruq45/on_some_lcd_monitors_this_page_will_cause_the/ https://www.reddit.com/r/InternetIsBeautiful/comments/2ruq45...
- AStonesThrow 1y ago[dead]
- deleted 1y ago[deleted]
- sneak 1y agoSure, but he’s using computer/phone speakers and mics and audio interfaces. These can’t generally produce or sample frequencies above 24kHz.