
The Mathematical Genius of Auto-Tune - wallflower
https://priceonomics.com/the-inventor-of-auto-tune/
======
jeremysalwen
>The equations that do autocorrelation are computationally exhaustive: for
every one point of autocorrelation (each line on the chart above, right), it
might’ve been necessary for Hildebrand to do something like 500 summations of
multiply-adds... >Hildebrand realized he was limited by the technology, and
instead of giving up, he found a way to work within it using math. “I realized
that most of the arithmetic was redundant, and could be simplified,” he says.
“My simplification changed a million multiply adds into just four. It was a
trick — a mathematical trick.”

I think this is the article's way of dramatizing the standard way of
calculating the autocorrelation using the convolution theorem:
[https://en.wikipedia.org/wiki/Autocorrelation#Efficient_comp...](https://en.wikipedia.org/wiki/Autocorrelation#Efficient_computation)

~~~
make3
at the era of deep learning, no one is impressed by their 500 summations of
multiply adds, or 1 million multiply adds. A geforce 1080ti does 11.3 TFlops,
with a T, that's 11 300 000 000 000 floating point operations per second..

~~~
jdietrich
Audio DSP has become much more sophisticated now that we've got cycles to
burn. RX and Melodyne are practically voodoo.

[https://www.youtube.com/watch?v=OVD7unKgkYo](https://www.youtube.com/watch?v=OVD7unKgkYo)

[https://www.youtube.com/watch?v=9FScFKuXXM0](https://www.youtube.com/watch?v=9FScFKuXXM0)

~~~
TheRealPomax
I have no idea how RX6 does some of the stuff I make it do - all I know is
that it does it better than I could have asked for.

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renaudg
It's worth mentioning that even if Auto-Tune has pioneered the field and is
now almost a mainstream househould name (much like Photoshop), nowadays all
the cool kids are on Melodyne, which is frankly black magic :
[https://www.youtube.com/watch?v=9FScFKuXXM0](https://www.youtube.com/watch?v=9FScFKuXXM0)

~~~
renaudg
Another crazy application of Melodyne : turning minor key "sad" songs into
"happy" major key ones

[http://theweek.com/articles/467109/sad-songs-made-happy-
amaz...](http://theweek.com/articles/467109/sad-songs-made-happy-amazing-art-
turning-minorkey-songs-major)

------
svantana
Oh dear, this guy has no limit to his self-aggrandizement, and the interviewer
surely does very little to fact-check his outrageous statements. The facts are
more like: auto-tune is the combination of pitch detection and pitch shifting,
two problems that were extensively researched already. Even the details, like
using autocorrelation via FFT, was standard in the field at the time. This
type of pitch correction had already been done in academia, but passed off as
a curiosity. The truth is, the guy was at the right place at the right time,
nothing more than that. Computers were just becoming fast and cheap enough,
and plugin formats making this type of product practical were just being
deployed.

~~~
Nition
_Detecting_ pitch may be easy enough, but a lot of programs still seem to have
trouble adjusting pitch transparently without weird artifacts (without simply
changing the speed). That's something Auto-Tune does seem to manage better
than most.

~~~
svantana
Well there's a huge difference between monophonic and polyphonic pitch
shifting. Monophonic pitch shifting (especially in the sub-semitone range that
Auto-Tune does) has been done with high quality since the 1970's.

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bllguo
I thought from the title that it goes into the mathematics. Unfortunately all
the article says w.r.t math is a hand-wavy explanation of autocorrelation. But
it was an interesting story about the life of Auto-Tune's creator.

~~~
jsjohnst
Yeah, the “mathematical genius” is describing the author of Auto-Tune, not
Auto-Tune itself. Through me off a bit too.

~~~
pizza
I've worked with Hildebrand myself - he's one smart cookie, for sure.

edit/tidbit: he told me that the interview process for hiring new developers
goes like this: all the questions are straight out of K&R's _C Programming
Language_ , you have to get all of them correct, and so far only one
programmer has :P

~~~
jsjohnst
I have an eidetic memory and have read that book multiple times, so there’s a
fair chance I’d pass. That said, if I was given that interview as you
described, I’d get up and walk out. Interviews like that prove absolutely
nothing useful to evaluating a candidate and thus are a waste of time.

~~~
the_d00d
Why read it multiple times? Just close your eyes

~~~
mikestew
Because the eidetic memory only lasts for a few minutes. The commentor might
have meant to use the phrase “photographic memory”, but that has thus far been
shown to be myth. But, really, the post was about “I’m smart, and I’d just
march right out of that interview”, ignoring that it was just a cute anecdote,
so I guess it’s irrelevant. Nice catch, though. :-)

~~~
jsjohnst
Mostly just a cute anecdote is fair, but wasn’t what I was replying to one
too? ;)

Seriously though, I’m tired of folks doing stupid counterproductive interviews
and then parading them as a good thing.

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MichailP
Are there some examples of Auto-Tune used with more subtle settings? Famous
Cher song used it at setting 0, robotic sounding one, but there are 10 more to
go, and they are increasingly more subtle.

Also related to this, at least I think, is the issue of turning recording into
midi or sheet music. Now that would be a killer app... There is some good
software out there, such as Melodyne, but it requires a lot of manual work and
tweaking.

~~~
taco_emoji
I _suspect_ this is one example:
[https://www.youtube.com/watch?v=BYmn4E-kPSo](https://www.youtube.com/watch?v=BYmn4E-kPSo)

The lead singer's voice just sounds so thin, and unnaturally on-key (no
vibrato).

I think you'd be hard-pressed to find verifiable examples because those higher
settings are probably mostly used to cover up poor singing, and so nobody
involved is going to volunteer that information.

~~~
criddell
As someone who isn't a fan of vibrato, I've always suspected that some singers
use it strategically to cover up pitch issues.

FWIW, I don't think modern auto-tune plugins have a problem pitch correcting
singers using vibrato.

~~~
vkjv
Melondyne is great with this. Complete lack of vibrato is usually an obvious
sign.

I think auto-tuners get a bad rap. As an amateur musician, subtle corrections
in post-production can save me _days_ of recording to get the right take.

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pcsanwald
The ubiquity of auto-tune is particularly interesting because most people
don't seem to have a lot of pitch sensitivity. Tons of very famous recordings
are slightly out of tune and no one seems to complain, ever.

I'd imagine its popularity is more due to convenience rather than demand.

~~~
amelius
I think slightly out of tune often sounds better (more natural) in all genres
except perhaps classical.

~~~
mrob
The one genre I can think of where perfect tuning is essential is barbershop
music. The defining feature of the genre is chords sung with just intonation
and no vibrato, which makes it easy to hear if any of the singers are out of
tune. See:

[https://en.wikipedia.org/wiki/Barbershop_music#Ringing_chord...](https://en.wikipedia.org/wiki/Barbershop_music#Ringing_chords)

~~~
baddox
A lot of barbershop albums, probably most recent ones, are pretty heavily
pitch-corrected. It doesn’t bother me that much, but I almost always prefer
live barbershop recordings.

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smelterdemon
I had always assumed that Auto-Tune had evolved from or was an advanced form
of Vocoder (likely from the similar "robot" effect extreme applications of
Auto-tune gives).

I've been working on a relatively simple real time music/audio processing
project on an Arduino (identifying tempo and using it to create interesting
lighting effects for a Halloween costume) and it's an interesting challenge.
Extracting any kind of useful information about the underlying musical
structure from polyphonic audio is an incredibly hard problem. Add to that
limited hardware and the kind of sampling rate you need to capture music
(upwards of 40kHz if you want to capture everything you can hear) and you have
to get creative.

~~~
soylentcola
It's definitely a challenge with something like a microcontroller. My coding
skills are borderline nonexistent (but then again, that's part of why I'm
experimenting with Arduino in the first place) but I've messed around with
using some FFT code published by others to get audio to affect some LED
strips. So far the results have been mixed.

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pizza
What he (Andy, or was it someone else at Antares? I forget..) told me is that
raspy heavy metal vocals are the one type of vocal that doesn't really _work_
with Auto-Tune that nonetheless constantly get requested to get to work

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purequest
wondering if anyone has listened to Guns N Roses live this past year or so.
Axl Rose's voice sounds amazing, considering his age, style of singing, and
his well documented hard living. Having listened live at coachella and watched
online, im wondering if its possible they are doing it live in real time now.

~~~
renaudg
Of course it's being done live :

[http://www.antarestech.com/products/detail.php?product=Auto-...](http://www.antarestech.com/products/detail.php?product=Auto-
Tune_Live_2)

Also as a $349 rack device : [https://www.amazon.com/Tascam-Producer-
Processor-Antares-Aut...](https://www.amazon.com/Tascam-Producer-Processor-
Antares-Autotune/dp/B004OA6JU2)

