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Misha comments on Harry Potter and the Methods of Rationality discussion thread, part 15, chapter 84 - Less Wrong Discussion

3 Post author: FAWS 11 April 2012 03:39AM

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Comment author: [deleted] 11 April 2012 10:43:29PM 15 points [-]

I'm experimenting with reproducing the sound of the really horrible humming in Mathematica. I haven't changed the duration of notes yet, but I've experimented with trying to make things sound as horribly off-key as possible. I've started out with just changing the pitches of the notes by adding normally-distributed noise. So far the main discovery I've made is that for greater effect, the magnitude of the change should be proportional to the length of the note. Any ideas for things to try?

I'm using MIDI sounds, which are the simplest to set up, but also have the drawback that every pitch must correspond to an integral semitone, which limits how horrible things can sound. Also, what is a good standard MIDI instrument for simulating humming?

Comment author: 75th 12 April 2012 11:02:21PM *  8 points [-]

I'm not sure how much music you know, and I'm not sure how much music Mathematica knows, so if this is all Greek or too hard, disregard it all:

Try different diatonic modes and different scales altogether. Switch from Major to Phrygian in the middle of a phrase. Switch to different sets of keys depending on whether consecutive tones are ascending or descending. Use a lot of Locrian mode, it is generally wrong-sounding. Try mapping diatonic scale degrees to octatonic ones somehow, and switch between the two octatonic scales at random. See if you can produce a portamento between two notes, and use it a lot when two notes are separated by only a semitone.

Comment author: Bill_McGrath 16 April 2012 02:23:26PM 0 points [-]

Additionally, switch tunings at random. This would be extremely difficult, but I'd imagine the disorientation caused would be related to how difficult it is. Switch from 12-ET to Pythagorean to Arabic to some obscure Baroque tuning, and base them all on different pitch centres.

Comment author: gjm 16 April 2012 08:54:18PM *  2 points [-]

When what you're listening to is purely melodic (like humming) I think such differences would either be unnoticeable or indistinguishable from just humming out of tune, to all but the most expert listeners.

A whole Pythagorean comma -- i.e., all the out-of-tune-ness you can get from Pythagorean tuning, crammed into a single interval -- is only about a quarter of a semitone. A quarter-comma meantone "wolf fifth" is actually even worse than this, but it's still only about 1/3 of a semitone.

If you have a computer with Python on it, you could grab the code from my discussion elsewhere in the thread with thescoundrel and experiment; I think you'll find that the sort of tuning-switching you describe would be altogether too subtle to be very effective as psychological warfare. [EDITED to add: in particular, I found that to my ears a quarter-tone error is quite often obtrusively unpleasant but a quarter-semitone is generally no worse than "a bit out of tune".]

Comment author: Bill_McGrath 17 April 2012 09:49:23AM 0 points [-]

Hmm. You're probably right. I've experimented with different tunings but I didn't play anything purely melodic. The effect is probably a lot more apparent when you're dealing with intervals rather than just pitches.

That said, changing the central pitch that the temperament is based around makes the differences bigger again; but that's not too useful as a tool for actually creating this melody. I think it'd be noticeable for the arabic tuning system too; that's extremely different to Western temperaments.

Comment author: [deleted] 12 April 2012 07:53:14PM 17 points [-]

After several hours of experimentation, I have figured out what the trick is. Quirrell did nothing except hum the same song for four hours. The Auror's mind filled in the rest. After four hours of listening to the same fifty-one notes over and over again, I'd be calling code RJ-L20 too.

Comment author: loserthree 13 April 2012 01:11:17AM 3 points [-]

On the one hand, I once listened to "Why Don't We Do It in the Road?" for three days straight. I had not stopped enjoying it when I stopped listening to it. (My roommates and guests did not share my enthusiasm, but I don't think they ever liked the song.)

On the other hand, while attempting to transfer a customer to the appropriate party I once listened to "Unchained Melody" for almost an hour. I didn't snap (it was a mill of a call center, so public nervous breakdowns were not unheard of), but the piece gained the ability to infuriate me even without the extra hours and fuck-with-your-brain inconsistency.

Comment author: buybuydandavis 12 April 2012 08:21:56AM 5 points [-]

EY is one hilarious fellow. He should do standup. The Horrible Humming was just too funny.

And interesting too, because you wonder if it could work.

Comment author: David_Gerard 12 April 2012 08:06:36PM *  9 points [-]

I am reminded of the first time Australian musician Lester Vat did his famous show Why Am I A Pie? (there's audio and video there.) He got up on stage at a rock'n'roll pub - it was a "What Is Music?" weird noise festival, but no-one expected this - went up to the microphone, and for forty-five minutes, just repeated the words:

"Why ... am I ... a pie?"
"Why ... am I ... a pie?"
"Why ... am I ... a pie?"

After fifteen minutes people didn't even have the energy left to tell him to fuck off. By twenty minutes people were slamdancing to it.

Repetition. It's powerful stuff.

Comment author: Jonathan_Elmer 13 April 2012 05:50:34AM 0 points [-]
Comment author: Alsadius 13 April 2012 03:45:25AM -2 points [-]

After three minutes, I'd be out of the bar and telling the manager not to expect me back.

Comment author: pedanterrific 13 April 2012 03:57:36AM 3 points [-]

it was a "What Is Music?" weird noise festival

Comment author: Alsadius 13 April 2012 05:28:10AM 1 point [-]

Correction: After I saw the sign, I'd realize that people have far too much time on their hands, and go home without setting foot in the bar.

That said, even the sort of people who go to such events probably have some limits.

Comment author: Percent_Carbon 13 April 2012 06:33:13AM 4 points [-]

That said, even the sort of people who go to such events probably have some limits.

Yes. It sounds like it takes them twenty minutes to start making the best of things.

Comment author: Percent_Carbon 12 April 2012 09:47:37AM 10 points [-]

Tolerance for rejection is a much harder qualifier to meet for success in standup than being funny is. Just, you know, so you know.

Comment author: kilobug 12 April 2012 04:12:57PM 2 points [-]

The Horrible Humming was great in itself, but it felt a bit artificial to me : why didn't the Auror just cast a Quietus charm ? Silencing prisoners with a gag is not that unusual in the Muggle world, and I would definitely except the wizards to use a Quietus charm or equivalent if a prisoner started to bother the Aurors with sound. It's not like Wizard Britain is very respectful of human rights of prisoners and that gags (mundane or magical ones) would be felt a non-acceptable behavior.

Comment author: loserthree 12 April 2012 04:18:24PM 7 points [-]

Quirrell would probably have sneezed it away, again.

Comment author: kilobug 12 April 2012 04:38:44PM *  1 point [-]

I also really doubt that any police force would let a prisoner resist them that way again and again, they would call reinforcement and break him. Even if he didn't do anything before, just resisting police forces is a criminal in many places, and it would really surprise me if Wizard Britain, with its awful human rights record, would let that go.

Edit : unless there is something much, much deeper at work here. Like Quirrel imperiusing or controlling in another way some high-ranking officers.

Comment author: loserthree 12 April 2012 05:03:35PM 5 points [-]

I also really doubt that any police force would let a prisoner resist them that way again and again, they would call reinforcement and break him.

It happens they did not. We know that, because he isn't broken and there's no sign they tried, other than the mention that he has apparently sneezed more than once. Also, he's not under arrest.

The Defense Professor of Hogwarts was being detained, not arrested, not even intimidated.

Magical Britain has a history of exceedingly powerful individuals that the muggle world just doesn't. It is not unreasonable that law enforcement developed differently as a result.

Comment author: pedanterrific 12 April 2012 05:01:02PM 11 points [-]

Wizarding police have to allow for the fact that some possible prisoners (Dumbledore, Grindelwald, Voldemort) are capable of beating up the whole police department put together. When someone displays surprising power, it makes sense to back off, at least until you're sure you can take him.

Comment author: kilobug 12 April 2012 06:01:17PM 1 point [-]

Hum, in canon at least, when they try to arrest Dumbledore at the end of tome 5 (HP and the Order of the Phoenix) they don't seem that hesitant to arrest him, as soon as they have proof he's doing something illegal, and they seem quite surprised he escaped.

But that could be a point of divergence between canon and HP:MoR, especially if the head of the Auror is very intelligent in HP:MoR, she could know about not escalating conflicts too easily.

Comment author: pedanterrific 12 April 2012 06:16:47PM 11 points [-]

Yeah, MoR has a much more well-thought-through concept of what it means to be a powerful wizard, and the difference between that and a normal wizard.

And even in canon, I'm not sure it makes sense for them to be surprised he could escape- everyone thinks of Dumbledore as the most powerful wizard alive- but they could have conceivably been expecting him not to attempt to resist arrest, because he's generally more law-abiding than that.

Comment author: Velorien 12 April 2012 04:55:24PM 3 points [-]

To cast the charm would be effectively to admit defeat before an unarmed prisoner (in a way that calling in a replacement according to standard procedure wouldn't), and also to be roundly mocked by other Aurors if they found out. Or so the Auror in question presumably thought.

Comment author: buybuydandavis 12 April 2012 08:10:54PM 5 points [-]

Listening and watching - monitoring - appears to be part of the job.

Because of the humor, I'm willing to suspend belief a little on realism. It's not a fundamental plot point. But it is funny.

Comment author: gwern 12 April 2012 08:06:08PM 1 point [-]

Casting the charm is also an admission of defeat.

Comment author: thescoundrel 11 April 2012 10:50:45PM 12 points [-]

I would think the real key to horrible humming would not be to have it be uniformly horrible, but so close to brilliant that the horrible notes punctuate and pierce the melody so completely that it starts driving you mad- a song filled with unresolved suspensions, minor 2nds where they just should not belong, that then somehow modulate into something which sounds normal just long enough for you to think you are safe, when it collapses again, and the new key is offensive both to the original and to the modulation. This is not just random sounds, this is purposeful song writing, with the intent to unsettle- in my mind, something like sondheim at his most twisted, but without any resolution ever.

Comment author: [deleted] 11 April 2012 10:58:17PM 5 points [-]

Well, first we're dealing with variations on a specific tune. The reason I suspect that random variations might work well is that if the probability of a change is sufficiently low, it would have exactly the effect you suggest: mostly the original "Lullaby and Goodnight", but with occasional horrible. Of course, if I were actually a cruel genius, I could do better, but it would be foolish of me to admit to being one.

Another reason random changes might work well is that they are by definition unexpected. If I did something purposeful, it would have a pattern; the real Quirrell might break that pattern by observing his victim's reactions, but not having a pattern at all might also be an interesting thing to try.

Comment author: Percent_Carbon 12 April 2012 07:01:29AM 1 point [-]

My music theory is rusty and anyway underdeveloped. But I don't think individual notes can be disturbingly off key. It is the relationship between notes that takes them out of key. A single note of any frequency will produce harmonics with anything in the environment that is capable of responding, and thus create its own meager, on key accompaniment.

I think MIDI keeps you from even approaching the kind of terrible close but not quite right tones you want to reproduce.

Comment author: 75th 12 April 2012 11:10:21PM *  2 points [-]

Changing one individual note in a monophonic tune absolutely can be horribly off key. Melody is harmony, and harmony is counterpoint; even with a single voice humming, if the tune is "classical" enough your brain understands intuitively where the chord changes are and what the bass line should be.

You don't need microtonal pitches to violently defy people's expectations.

(EDIT: Though you almost certainly do need microtonal pitches to precisely mimic the effects described in the text. But I think you certainly could do something horrible without them.)

Comment author: thescoundrel 12 April 2012 01:44:33PM 1 point [-]

I don't think you need to even venture into the world of quarter pitches in order to create horrible humming. To give an idea of a song that twists your expectations of keys and time signatures and melodic progression, and breaks it in specific ways to ramp tension, check the epiphany from sweeney todd.

Comment author: Alsadius 13 April 2012 03:35:06AM 0 points [-]

I didn't really notice anything wrong with that. it jumped around a lot, and it wasn't especially good, but it didn't much bother me.

Comment author: thescoundrel 13 April 2012 03:45:32AM 0 points [-]

I forget that when I listen to it, I have the background of the story and buildup already, so I start with different expectations- perhaps not the best example.

Comment author: Alsadius 13 April 2012 04:03:00AM 0 points [-]

Also, I've listened to a fair bit of weird proggy music.

Comment author: Percent_Carbon 12 April 2012 02:01:26PM *  0 points [-]

There's a continuous spectrum of pitch. The character is kind of showing off, like he always kind of is.

He's probably hitting notes that are multiples of irrational numbers when described in Hertz.

Retracted because it seemed the best way to acknowledge the correction: the vast majority of common musical notes are multiples of irrational numbers when described in Hertz.

Comment author: arundelo 12 April 2012 02:59:03PM 8 points [-]

FYI, in the tuning system commonly used for western music, all notes except A are irrational frequencies in hertz. Example: A below middle C is 220 hertz, and middle C is

(220 * (2 ^ (1/12)) ^ 3) hertz ~= 261.6255653006 hertz.

(To go up a half step, you multiply the frequency by the 12th root of 2.)

Comment author: Alsadius 13 April 2012 03:41:47AM 2 points [-]

At risk of derail, how the hell did they ever get a twelfth root into music?

Comment author: [deleted] 13 April 2012 04:08:49AM 6 points [-]

We think of intervals between tones as being "the same" when there is a constant ratio between them. For instance, if two notes are an octave apart, the frequency of one is twice the other.

Thus, if we want to divide the octave into twelve semitones (which we do have twelve of: C, C#, D, D#, E, F, F#, G, G#, A, A#, B) and we want all of these twelve semitones to be the same intervals, then we want each interval to multiply the frequency by 2^(1/12).

Comment author: Alsadius 13 April 2012 05:26:52AM 2 points [-]

Every part of that makes sense except for the lack of E# and B#, and why x2 is called an octave. Thanks for the info, and for reminding me why musical theory is one of three fields I have ever given up on learning.

Comment author: Benquo 13 April 2012 04:07:19AM *  2 points [-]

Look up "equal temperament." There are 12 half-steps in an Octave, after each octave the frequency should double, and the simplest way to arrange it is to make each step a multiplication by h=2^(1/12) so that h^12=2.

Many people report that "natural" intervals like the 3:2 and 4:3 ratio, sound better than the equal temperament approximations, though I don't hear much of a difference myself.

Comment author: thomblake 13 April 2012 08:08:39PM 0 points [-]

It's really obvious if you expect any decent math to invoke exponents of 2.

Comment author: thescoundrel 12 April 2012 02:11:23PM 4 points [-]

The vast majority of humans don't have perfect pitch, so the specific pitch of the note is far less important than the relationships to the notes surrounding them. I agree that he is rather showing off, but unless you spend a very large amount of time ear training, you likely cannot tell when a note is a quarter tone sharp or flat. However, just like there are cycles of notes that always sound amazing together when you run them through variation (see the circle of 5ths), there are notes that sound horrible and jarring. Furthermore, the amount of time it takes to reliable sing quarter tones is ridiculously high- it is something that life long trained musicians cannot do. (Of course there is another discussion about how our formulation of music causes this, but lets set that aside for now.) I think it is far more likely that he has studied a circle of 7th's and 2nd's, or something to that effect- he has created a musical algorithm where the pattern itself is so convoluted, it is not intuitively detected, and the notes/key changes produced so horrible, it wears on the mind.

Comment author: gjm 12 April 2012 04:06:39PM 1 point [-]

Even without a lot of ear training, you can quite likely hear if a note is a quarter-tone out relative to its predecessors and successors.

Comment author: thescoundrel 12 April 2012 05:09:11PM 3 points [-]

Here is a quarter tone scale. While the changes are detectable right next to each other, much like sight delivers images based on pre-established patterns, so does hearing. When laid out in this fashion, you can hear the quarter tone differences- although to my ears (and I play music professionally, have spent much time in ear training, and love music theory) there are times it sounds like two of the same note is played successively. Move out of this context, into an interval jump, and while those with good relative pitch may think it sounds "pitchy", your mind fills it in to a close note- this is why singers with actual pitch problems still manage to gain a following. Most people cannot hear slightly wrong notes. However, none of this approaches the complexity of actually trying to sing a quarter tone. The amount of vocal training required to sing quarter tones at will is the work of a master musician- much like the the person who can successfully execute slight of hand at the highest level is someone who spends decades in honing their craft.

Comment author: gjm 12 April 2012 08:49:51PM 7 points [-]

I just tried some experiments and I find that if I take Brahms's lullaby (which I think is the one Eliezer means by "Lullaby and Goodnight") and flatten a couple of random notes by a quarter-tone, the effect is in most cases extremely obvious. And if I displace each individual pitch by a random amount from a quarter-tone flat to a quarter-tone sharp, then of course some notes are individually detectable as out of tune and some not but the overall effect is agonizing in a way that simply getting some notes wrong couldn't be.

I'm a pretty decent (though strictly amateur) musician and I'm sure many people wouldn't find such errors so obvious (and many would find it more painful than I do).

Anyway, I'm not sure what our argument actually is. The chapter says, in so many words, that Q. is humming notes "not just out of key for the previous phrases but sung at a pitch which does not correspond to any key" which seems to me perfectly explicit: part of what makes the humming so dreadful is that Q. is out of tune as well as humming wrong notes. And yes, the ability to sing accurate quarter-tones is rare and requires work to develop. So are lots of the abilities Q. has.

(Of course that doesn't require that the wrong notes be exactly quarter-tones.)

Python code snippet for anyone who wants to do a similar experiment (warning 1: works only on Windows; warning 2: quality of sound is Quirrell-like):

import random, time, winsound
for (p,d) in [(4,1),(5,1),(7,3),(None,1), (4,1),(5,1),(7,3),(None,1), (4,1),(7,1),(12,2),(11,2),(9,2),(9,2),(7,1),(None,1), (2,1),(4,1),(5,3),(None,1), (2,1),(4,1),(5,3),(None,1), (2,1),(5,1),(11,1),(9,1),(7,2),(11,2),(12,4)]:
if p is None: time.sleep(0.2*d)
else: winsound.Beep(int(440*2**((p+1*(random.random()-0.5))/12.)), 200*d)
Comment author: David_Gerard 12 April 2012 09:04:49PM *  1 point [-]

See, I'm the sort of person that reads that and wants to buy that record. Probably from the small ads in the back of The Wire.

(Breaking musical rules sufficiently horribly is a well-established way to win at music, even if you're unlikely to get rich from it. Metal Machine Music actually got reissued and people actually bought it.)

Comment author: q4-g03olf 12 April 2012 02:35:39AM 3 points [-]

You might check out a program called Max/MSP if you want to get really deep into this stuff. It handles conversions between MIDI and audio signal pretty elegantly. Other ideas..

You might try making notes that change pitch continuously You might try putting the breaks in parts of the music where we expect it to continue. MIDI "doo" or other synth voice instruments tend to sound pretty maddening on their own without much special effort. Maybe layer in helicopter sounds or applause to simulate breathiness?

Comment author: David_Gerard 12 April 2012 09:03:49PM *  1 point [-]

The FluidSynth sound fonts are quite nice within their instruments' usual range, but do try going up or down a bit far for great lulz.

Comment author: enoonsti 13 April 2012 05:21:03AM 0 points [-]

Just out of curiosity, what's your set-up (MIDI controller, software, etc)? I have an old Oxygen 8, Ableton Live 8, and some VSTs. My music sucks.

Comment author: David_Gerard 13 April 2012 07:50:10AM 0 points [-]

LMMS, a cheap'n'cheerful open source knockoff of FruityLoops. It's basically a toy (e.g., it has no undo. Seriously). But fun.

Comment author: Bill_McGrath 12 April 2012 06:00:55AM *  2 points [-]

When I was reading that part, all I could think was "Man, I have to try do that..."

I'm using MIDI sounds, which are the simplest to set up, but also have the drawback that every pitch must correspond to an integral semitone, which limits how horrible things can sound.

There are ways around this: a program called Scalar allows you to build microtonally tuned scales and set them up to be controlled by MIDI. Also, Native Instruments' Kontakt allows you to change the tuning of instruments and map the new tuning to a keyboard.

Scalar is free but hard to use: I was never actually able to figure out how to set it up to hear the scales I'd built - but my laptop seems to have a grudge against MIDI devices anyway. Kontakt is a lot easier to use but costs a couple of hundred euro.

Comment author: Bill_McGrath 12 April 2012 10:00:21AM 0 points [-]

Also: Most decent DAWs will have a pitch bend function, that might be an easier way again to get around it. I'll check if Reaper can do it, and get back to you. (Also, I might do this myself once the semester is over.)

Comment author: Bill_McGrath 16 April 2012 02:29:37PM *  1 point [-]

This is might be my favourite comment thread on all of Less Wrong. Terrible pity that the poster left!

EDIT: Semi-relevant.

EDIT 2: I have a great love for some technically awful music that I find still entertains me loads. I inflict The Shaggs on my friends in college every excuse I get.