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Ask the Expert

Ask the Expert

Harold Hildebrand

Harold Hildebrand, or "Dr. Andy" as he is widely known, founded Antares Audio Technologies in 1990. Antares develops high-tech digital signal processing (DSP) products for the music industry. Its first product was the Infinity software. Allowing string ensembles and other complex sounds to be used in synthesizers, the program cleared the final technological hurdle that enabled symphonic film scores and CDs you hear today to be created entirely by synthesizers. Dr. Andy's most significant development at Antares is Auto-Tune, which puts a singer's pitch in tune, in real-time, without artifacts. Virtually all music studios today use Auto-Tune to fix singers' intonation (a practice whose virtues music-industry pundits vigorously debate). Dr. Andy also designs and manufactures hardware versions of Auto-Tune, and he is working on DSP products specifically for singers. Before founding Antares, Dr. Andy worked in the geophysical industry and was a cofounder of Landmark Graphics, where he designed and implemented software applications for 2-D and 3-D interactive seismic-interpretation products. Dr. Andy received his Ph.D. in electrical engineering from the University of Illinois in 1976, specializing in random processes and estimation theory. He and his wife, Georganna, live in a redwood forest near Felton, California, where they have two dogs, two cats, and uncountable raccoons. Dr. Andy's hobby is fine woodworking, from felling and milling native trees to building furniture and making art.

On July 7, 2009, Harold "Dr. Andy" Hildebrand answered viewer questions about Auto-Tune, the implications of its use among professional musicians, and more. Please note we are no longer accepting questions, but see Pitch Perfect and the Links & Books section for additional information.

Q: Dr. Hildebrand,

Do you think that recording artists from the previous era (before digital recording techniques like Auto-Tune were available) were more talented because they actually had to know how to sing in tune? And do you think there are famous singers who don't know that they're singing out of tune because they rely on Auto-Tune so much?
Ryan, La Mesa, California

A: Hi Ryan,

How about Marilyn Monroe singing "Happy Birthday" to JFK? That sounded pretty bad. Cheating in the old days used endless retakes to get a final result. It's easier now with Auto-Tune. The real impact of Auto-Tune is that it changed how studios produce vocals.

Famous singers who use Auto-Tune likely learn new distinctions about intonation as they develop as artists.

Q: Auto-Tune is capable of shifting individual pitches to produce a more desirable sound, but can the software be used to change the key of an entire song in a few clicks, or would you have to shift each note manually? Also, would the clarity of the track be distorted if this was achieved?
Matt Snyder, Toledo, Ohio

A: Matt,

The latest Auto-Tune has a pitch-shifting control that, when used with formant compensation, allows easy key changes while preserving the original character of the performance (including pitch errors, if desired).

Q: There has been mountains of controversy regarding your software and how it's turning non-singers into singers who can only perform in the studio. Don't you think that's cheating the public, who might not be aware that these so-called singers can only sing in tune with the help of your software? Isn't there enough fluff and superficiality in the entertainment industry as it is?
Dan Marois, Canada

A: Dan,

Just as GM (R.I.P.) didn't set out to create auto accidents, we didn't intend non-artistic uses of Auto-Tune. Pop music is entertainment, like movies. Is the actor who plays Batman "cheating" because he can't really fly?

Q: Do you think there is any particular genre of music in which Auto-Tune is prevalently used? Also, is there any possible way for listeners to discern the difference between music altered with Auto-Tune or music without?
Grade 11, Crescenta Valley High School, La Crescenta, California

A: Dear Grade 11,

Good questions!! Auto-Tune is pervasively used, often just to touch up a note or two in a song. When used without excess, it's difficult to notice Auto-Tune's presence. However, being a trained musician, it's clear to me that if every note of a singer's performance is in tune, Auto-Tune has been used.

Q: What kind of mathematics are used in your Auto-Tune software?
Nikhil Kunapuli, Bridgewater, New Jersey

A: Nikhil,

Multiplications, additions, and a few divisions, but designed by an extensive theoretical foundation in Digital Signal Processing encompassing the physical principles of sound production, physics of hearing, disciplines of modeling, filtering, linear systems theory, estimation theory, numerical analysis, calculus, music theory and other disciplines. Pretty much.

Q: Hi Dr. Andy,

I read on your website that Auto-Tune is based on software you wrote to interpret seismic data for oil companies. It seems like a bit of a stretch to go from analyzing seismic waves to a singer's voice. Can you explain how your work as a geophysicist was useful for creating music software?

A: Hi Anonymous,

Seismic data processing involves the manipulation of acoustic data in relation to a linear time varying, unknown system (the Earth model) for the purpose of determining and clarifying the influences involved to enhance geologic interpretation. Coincident (similar) technologies include correlation (statics determination), linear predictive coding (deconvolution), synthesis (forward modeling), formant analysis (spectral enhancement), and processing integrity to minimize artifacts. All of these technologies are shared amongst music and geophysical applications.

Q: I converted some of my old LPs into MP3 files so I could listen to my old music, but it has picked up all of the scratches from the vinyl records. Could the Auto-Tune software correct for the scratches? Is this available commercially??
Roger Griffin, Irvine, California

A: A: No. Yes. In that order.

Q: Could Auto-Tune be built into microphones on karaoke machines and therefore save us from all of those awful renditions of loved songs?
Rajah, Houston, Texas

A: How about an iPhone? (hint, hint)

Q: As a music lover and a computer programmer, I am so intrigued by Auto-Tune. I have two questions:

1) What language(s) is/are used to program it?

2) Jay-Z, a hip-hop icon, has a new album to be released later this year with the first single called "Death of Auto-Tune." Care to comment?
Leckey Swanson, McCook Lake, South Dakota

A: Auto-Tune is programmed in C++ for the Mac and PC platforms. It runs as a plugin in software applications called DAWs (Digital Audio Workstations) published by various other companies. Auto-Tune also runs on various 56K class DSP chips for which it is programmed in assembler.

Concerning the Death of Auto-Tune, see

Q: I think I can usually detect the use of Auto-Tune, but I've never scientifically tested myself. How often can people tell that a track has been auto-tuned? Have any controlled studies been done?
Sam Kennerly, Philadelphia, Pennsylvania

A: At one extreme, Auto-Tune can be used very gently to nudge a note more accurately into tune. In these applications, it is impossible for skilled producers, musicians, or algorithms to determine that Auto-Tune has been used. On the other hand, when used as an effect, such as in hip-hop, Auto-Tune usage is obvious to all. Everything in between is subject to an individual's unique listening skills.

Q: What do you personally think of the "out-of-this-world" uses the recording industry has put Auto-Tune to?
Chip Davis, Lumberton, North Carolina

A: I find the obvious popularity of Auto-Tune to be personally gratifying because I feel I have made a difference to the music community.

Q: Are you a good singer, Dr. Andy?

A: I am a trained performing musician (flute) and composer. I have voice training and have participated in choirs and musicals. I can carry a tune just fine, but my voice is not particularly attractive.

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