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February 22

Graphic equalizers with perceptual frequency scale

Last time, I made the graphic EQ that use arbitrary frequency scale for spacing center frequencies. So the question is why most graphic equalizers have logarithmic frequency scaling in regards to spacing for center frequencies? And is it better to use 24-band Bark scale than typical log2 and 1/3rd octave spacing for GEQ since our hearing is actually linear at bass and logarithmic at anything else? 2001:448A:3042:7FD9:75AE:9537:3A9B:A23F (talk) 03:15, 22 February 2023 (UTC)[reply]

You also have to look at the effort for the operator to apply the settings. It should not be too many frequencies, otherwise it probably will not be set optimally , and if it was, there would be a lot of slider pushing. If you were using linear spacing, for high frequencies there would be far too many that could not be easily separated audibly. Also for the electronics, it is going to be much easier to make a algorithmically spaced set of controls, as the circuitry is going to be as simple as possible, without having a high-Q, with narrow bands. Graeme Bartlett (talk) 11:14, 22 February 2023 (UTC)[reply]

Most graphic equalizers have logarithmic spacing of center frequencies for the same reason my piano does. See A primer on graphic equalizers. Equalizers are used to modify music and here the human perception of pitch is well modelled by the Mel scale which is a logarithmic function of frequency. Aural discrimination of frequency occurs in the Cochlea of the inner ear. Each piano key maps to a position along the cochlea, bass notes deepest. I confirm that a semitone step at the lowest or the highest end of my piano sound similar, so the correctness of the logarithmic frequency model is apparent, at least to this western music listener. A graphic equalizer has a number of adjustable FIR (Finite Impulse Response) filters that typically varies from 7 on a domestic or in-car unit (center frequencies 60 - 150 - 400 - 1kHz - 2.4kHz - 6kHz - 15kHz), to 10-band (octave step), 15-band and 31-band (1/3-octave step) professional units. An extreme graphic equalizer with 88 steps duplicating each piano key in the Equal temperament scale of successive 2^1/12 ratio frequency steps could be built though I don't see a need for it. An operator may use a graphic equalizer to shape the sound power distribution in frequency to achieve various effects or to compensate for room acoustics and/or for the non-linearity of ear sensitivity which is always quantified on logarithmic frequency scales such as Robinson–Dadson curves (1956) or Fletcher–Munson curves (1933). I can't support the OP's implication that human hearing changes from logarithmic to linear near a bass music extreme such as piano A₀ 27.5 Hz. Graphic equalizers intended for other purposes than music may have different frequency step allocations. A device that lets you choose your center frequency, narrow or widen the bandwidth of surrounding frequencies that are affected, and also adjust the slope of those frequencies is called a parametric analyzer and is likely to use second‑order IIR (Infinite Impulse Response) filters. Philvoids (talk) 17:06, 22 February 2023 (UTC)[reply]

@Graeme Bartlett and Philvoids: In regards to the effort for the user to apply settings to EQ curve, while its true it takes a lot of effort to change a frequency curve of 120-band GEQ (which I don't see the need for it) given the fact adjusting the sliders takes time (maxing out first 2 bands on 10-band equalizer or first 5 bands on third-octave EQ to get a bass boost effect), I would agree that using different frequency scale affects the resolution and the amount of effort tradeoff for each frequencies; logarithmic frequency scale provides equidistant spacing on the same frequency scale as note frequencies (however, the bass frequencies will suffer from pre-ringing artifacts when it is in linear-phase mode as auditory perception is linear at bass frequencies and logarithmic at anything else, same goes for time resolution on constant-Q transform visualizations), while setting to linear frequency scale definitely gives too many control on higher frequencies and too few on bass frequencies. Most if not all frequency scales modeled on auditory system are approximately linear at bass frequencies and logarithmic at higher frequencies, so the resolution for a 24-band GEQ spaced on a Bark scale is somewhat in-between 7-band GEQ for the bass frequencies and slowly transitioning to 31-band one for higher frequencies. For the regards to EQ types, the parametric EQ is for anything precise and this is something that isn't being used often on casual listeners while commonly-used graphic EQs are easier to control as all the user have to do is just adjust the curve until the user found out the pleasant curve. Also, the FIR filters doesn't have to be linear-phase and most graphic EQs actually use IIR filters and the frequency response sometimes isn't perfectly flat when all bands are set to minimum or maximum value. 2001:448A:3046:59C8:693C:6C8F:8FD2:B68 (talk) 00:40, 23 February 2023 (UTC)[reply]

Chemistry

What is electrolyte — Preceding unsigned comment added by 129.0.99.165 (talk) 15:14, 22 February 2023 (UTC)[reply]

I think the article on oral rehydration therapy may be more useful than the electrolyte article. Abductive (reasoning) 15:34, 22 February 2023 (UTC)[reply]

Maybe so but see Electrolyte. An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Philvoids (talk) 17:13, 22 February 2023 (UTC)[reply]

Movie trivia

The following discussion has been closed. Please do not modify it.

It's NOT what plants crave. Or at least they'll tolerate pouring one drop per millennium of Gatorade, Powerade, Brawndo and similar drinks but if you keep increasing that amount at some point they die. Sagittarian Milky Way (talk) 19:17, 22 February 2023 (UTC)[reply]

What is going on with this question? Sorry for bolding/shouting, but the responses to this question are really making me wonder what exactly is expected for behavior on this reference desk? The IP asked a very simple definitional question. The first response suggests something that may be entirely unrelated as nothing in the IP question implies they are asking about sports beverages or anything that we would consume. The second answer, from Philvoids, actually seems like a good answer to the question. Then we have a third and completely random, to the point of being a non-sequitor, going off on a tangent about watering plants with Gatorade. Was anything involving plants even in the IP question, or any subsequent responses before that? Nope. So what is going on here? --OuroborosCobra (talk) 23:59, 22 February 2023 (UTC)[reply]

https://www.imdb.com/title/tt0387808/ Sagittarian Milky Way (talk) 00:14, 23 February 2023 (UTC)[reply]

That's not an answer to my question, and if you were trying to mimic that movie, I'm again asking what are we doing here? Is your purpose here to dumb things down to nonsense with your answers to questions? --OuroborosCobra (talk) 00:20, 23 February 2023 (UTC)[reply]

It's a funny comedy about a millennium-long reverse Flynn effect starting in the near future allowing 2 ubiquitous sports drink slogans to persuade USA to convert all tap water systems and irrigation to more profitable drinks causing soil electrolytes to rise till an average Joe of 2006 (botched suspended animation experiment) convinces the government to irrigate with water so America doesn't starve to death. Which takes a whole hour cause Brawndo's What Plants Crave! and It's Got Electrolytes! After an hour of using logic and reason Joe gave up and told everyone that he could talk to plants and they wanted water and that convinces them. Sagittarian Milky Way (talk) 01:33, 23 February 2023 (UTC)[reply]

So you are trolling legitimate questions on this reference desk. Cool. Again, why are we here? --OuroborosCobra (talk) 15:45, 23 February 2023 (UTC)[reply]

How close to men being irrelevant?

I'm curious how close science is to being able to taking two cells (either Monoploid like eggs or Diploid "normal cells") from Mammalian females and producing a viable cell with the genetic material from both females that can grow to adulthood? I don't have a good feeling for where we are on the scale of A) "They did it with mice last year, cows last month and Gibbons are scheduled for April" to B) somewhat more difficult than Star Trek Warp Drive. Naraht (talk) 19:06, 22 February 2023 (UTC)[reply]

You'd need artificial Y chromosomes to make cismen. Unless you have a transgender human (no transmen, that won't work). Sagittarian Milky Way (talk) 19:24, 22 February 2023 (UTC)[reply]

We could clone humans right now. All the males could die (or all but a rather high number (up to thousands) of random fertile men plus all other males which would mean death by genetic bottleneck without technology) and they could do the Dolly the sheep thing. _{I don't know if it's possible for the clone to not die quickly young like Dolly. But even if clone life expectancy is full-blown "life expectancy of donor at donation minus age of clone since conception" then if the lady is 18 the clone would probably have at least a few decades of adulthood.} Sagittarian Milky Way (talk) 20:45, 22 February 2023 (UTC)[reply]

As far as we know, cloned sheep do not have a reduced lifespan. Dolly died of an illness that appears unrelated to having been cloned. --Lambiam 22:34, 22 February 2023 (UTC)[reply]

If you're interested in reading about specific examples to see outcomes, we have List of animals that have been cloned and Category:Cloned animals. DMacks (talk) 22:40, 22 February 2023 (UTC)[reply]

My mistake. Why do I even remember generation old wrong hypotheses? Sagittarian Milky Way (talk) 22:47, 22 February 2023 (UTC)[reply]

See [1] Nil Einne (talk) 05:13, 23 February 2023 (UTC)[reply]

The technique would be similar to that used in cloning, but would be different in detail. In cloning, the nucleus of an oocyte is removed and replaced by that of a stem cell of the donor. In what you are proposing, the nucleus of the recipient oocyte would not be removed, but that of a donating oocyte would be added. I don't know if this has been attempted. --Lambiam 22:44, 22 February 2023 (UTC)[reply]

Girl Child of two Female

OP here. I am *not* talking about cloning a single individual. I am talking about creating a female from the Genetic material of two females, each parent contributing genetically half of their DNA. I don't think any of the above responses replied to that.Naraht (talk) 14:24, 24 February 2023 (UTC)[reply]

I think my last one did. --Lambiam 18:34, 24 February 2023 (UTC)[reply]

So I asked chatGPT "If the Great Basin were filled to overflowing, how deep would it be?"

as well as "where would the deepest point be?", and "where would it overflow?".

Hi!

of course all I got was very well structured and rapid (robot) hand waving, and "it depends", but,

What are the answers?

Thanks Saintrain (talk) 20:53, 22 February 2023 (UTC)[reply]

Given a good contour map, the point of overflow should not be hard to determine; it will correspond to a saddle point, where closed contours become open. Local minima should be inside small closed contours; if there are many it will take some effort to spot the lowest. Unfortunately, I did not find a usable contour map online. This one comes close, but is cut off at the edges before we can see the saddle point. --Lambiam 22:25, 22 February 2023 (UTC)[reply]

This is wrong. That park isn't close to all of it. Sagittarian Milky Way (talk) 22:38, 22 February 2023 (UTC)[reply]

Specifically, the Great Basin is vastly larger than Great Basin National Park. Cullen328 (talk) 00:20, 23 February 2023 (UTC)[reply]

@Lambiam Boy did that get me started! :-)

From: https://water.usgs.gov/GIS/metadata/usgswrd/XML/ha694c_ha1000gb.xml#stdorder

I downloaded: https://water.usgs.gov/GIS/dsdl/ha694c_ha1000gb.zip

which I converted to kml at: https://mygeodata.cloud/converter/shp-to-kml

to open in google earth, where I can draw a path around the perimeter and see the profile.

Fun times, Saintrain (talk) 23:44, 22 February 2023 (UTC)[reply]

It's probably near sea level and Mexicali. The bottom is Death Valley. Sagittarian Milky Way (talk) 00:32, 23 February 2023 (UTC)[reply]

So, how much sea-level rise would it take to convert Mexicali into North America's future Byzantium? {The poster formerly known as 87.81.230.195} 51.198.55.125 (talk) 08:22, 23 February 2023 (UTC)[reply]

Mexicali says it (probably downtown or a median or average) is eight meters above sea level, Great Basin shows a squiggly diagonal line from extreme southeast California to the southernmost part of the basin (in the Baja mountains), if that map is right the lowest point on that squiggly line should be where it'd overflow. Sagittarian Milky Way (talk) 17:01, 23 February 2023 (UTC)[reply]

The endorheic watershed is much larger than the lake you'd get if you filled it until overflow, because it also contains areas above the saddle point where the overflow would happen. So if you filled the Great Basin with water, you'd get multiple lakes, each overflowing via one saddle point into a river, connecting it to the next lake or eventually the sea or another watershed. For each of these lakes, one could find the deepest point and the overflow point. Just download the elevation data (see for example ASTER data) and write some code to find the contours. PiusImpavidus (talk) 10:07, 23 February 2023 (UTC)[reply]

Indeed it'd be low thousands of feet deep at the lowest part of Death Valley (282 feet below sea level) but only low hundreds of feet deep at the lowest part of the Salton Sink which reaches ~mid-200s feet below sea level. The Greatest Possible Salt Lake rim would be higher than the 4,236 ft altitude Bonneville Salt Flats bed, it couldn't possibly be the same lake as the Salton Sink. Sagittarian Milky Way (talk) 15:24, 23 February 2023 (UTC)[reply]