Wikipedia:Reference desk/Archives/Science/2023 November 23

= November 23 =

looking for term: sound effect when trying to sync up audio tracks of slightly different playback speeds
sound effect increases in pitch as the two tracks get closer to where they're in sync (before going down again), also cymbals sometimes sound washed out --2003:DD:E712:D329:9B0:7091:5F78:68E1 (talk) 01:10, 23 November 2023 (UTC)


 * Beat (acoustics). Modocc (talk) 02:22, 23 November 2023 (UTC)
 * Dubbing. 41.23.55.195 (talk) 09:28, 23 November 2023 (UTC)
 * Modocc, I don't thinks it's beat. I'm talking about pitch going up (then down) once and not a periodic variation in volume. If you'd like to hear it for yourself, import any song (preferably one with cymbals) into your audio editor twice, multiply playback speed of one of them by 0.001, add a few ms of silence (should be somewhere between 0 and difference in length), listen closely to section where tracks in sync (ignore parts where this is obviously not the case). --2003:DD:E712:D329:9B0:7091:5F78:68E1 (talk) 10:13, 23 November 2023 (UTC)
 * Pitch shifting, beatmatching. Or maybe even portamento? --Wrongfilter (talk) 10:17, 23 November 2023 (UTC)


 * I'm not familiar with the effect. That may be because I never deal with music. But I know that music has a spectrum with many frequencies and the lower frequencies would be in sync (offset less than a certain fraction of the period of the wave) before the higher frequencies. So slightly before getting in sync, the low frequencies show destructive interference whilst the high frequencies are added incoherently, leading to a perception of increased pitch. Even closer to sync, the low frequencies show constructive interference whilst some high frequencies show destructive interference, but music has a few powerful low frequencies (the fundamental, maybe the first harmonic) and many, weaker high frequencies (the higher harmonics), so this effect is less pronounced.
 * I don't know a term for this, other than interference. Maybe loss of fundamental? PiusImpavidus (talk) 11:01, 23 November 2023 (UTC)


 * It's essentially the same thing as Flanging, although there are several minor variants such as chorus. The linked article describes the effect and the origin of the name. 2A01:E0A:D60:3500:68C5:7DDC:3DF9:BA4D (talk) 13:54, 23 November 2023 (UTC)
 * Thanks for the explanation, PiusImpavidus, and yeah, flanging seems to be correct answer here. --2003:DD:E712:D3E2:F5A3:CC69:CD0C:8EA4 (talk) 01:48, 24 November 2023 (UTC)
 * Not only did I link to the wrong term my bits couldn't recall the term heterodyning (it was late). When tuning analog superheterodyne receivers (AKA radios) to a station one hears substantial differences in both volume and pitch. I haven't installed an audio mixer, thus I'm uncertain if the analog tuning effect matches yours. I recall it being different from the chorus effect of flanging. Modocc (talk) 14:47, 26 November 2023 (UTC)

Obstetrics
In humans, what was the fastest-ever childbirth in the world, from onset of active labor to the full expulsion of the baby (but excluding the time required to deliver the placenta)? (Question inspired by Flight Simulator X mission "Whiteout".) 2601:646:9882:46E0:C86:F258:B5A7:C94F (talk) 03:59, 23 November 2023 (UTC)
 * I know this isn't what you are asking, but an OB/GYN resident friend of mine performed an emergency C-section from first incision to "baby out" in 29 seconds. They must be timing these sorts of things, perhaps another person here has information on natural childbirths. Abductive  (reasoning) 04:42, 23 November 2023 (UTC)
 * Right, I should have been clear from the start that I'm asking about natural childbirths, not C-sections. 2601:646:9882:46E0:F81B:1D07:2C0A:DEA6 (talk) 23:51, 23 November 2023 (UTC)
 * I doubt that anybody was timing them. Clarityfiend (talk) 02:46, 24 November 2023 (UTC)
 * They absolutely time births, as they need to know how long the baby has gone without oxygen. See perinatal asphyxia. Abductive  (reasoning) 06:37, 24 November 2023 (UTC)
 * Isn't that after birth? Clarityfiend (talk) 09:40, 24 November 2023 (UTC)
 * Some before, some during, some shortly after. Read perinatal asphyxia. Abductive  (reasoning) 09:55, 24 November 2023 (UTC)
 * That's under what we call standard operating procedures for modern-day births. But there were literally billions of births from earlier times that occurred under all manner of different circumstances, and virtually none of them were ever timed, and those that were timed were not recorded in any systematic or searchable way. So, whatever data you may find to answer your question is going to be very severely limited to the recent past, and hence pretty meaningless, I'd have thought. -- Jack of Oz   [pleasantries]  21:56, 26 November 2023 (UTC)
 * Here's an article in The Atlantic that says a woman had her baby 12 minutes after her water broke. "It felt like being hit by a truck and dragged along behind." Abductive  (reasoning) 05:11, 27 November 2023 (UTC)
 * Wow, 12 minutes??? I've seen a video of one which took only 37 minutes, but this is probably the world record!  (Oh, and regarding the comment by User:JackofOz: I thought it was obvious that I was looking for recorded statistics???) 2601:646:9882:46E0:6DCC:D03D:49B0:1236 (talk) 08:41, 27 November 2023 (UTC)
 * Fair enough, but you did say "fastest-ever childbirth". Perhaps you meant to ask about "fastest recorded childbirth"? -- Jack of Oz   [pleasantries]  19:55, 27 November 2023 (UTC)
 * "Recorded" is implicit, because it's obvious that we'll never know about ones which haven't been recorded. 2601:646:9882:46E0:51DF:AAD3:4B5D:617C (talk) 00:11, 28 November 2023 (UTC)