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Instructions for using the auto-tune program yourself.

Installation instructions

This .zip archive contains the main function, autotune.m, as well as the helper routines pitchShift.m, fusionFrames.m, and createFrames.m. To install the program, first you must extract it from the archive. In Windows, this can be done by right-clicking on the .zip and selecting “extract here.” Similar methods exist for other operating systems. Next, copy all of the files to your MATLAB directory, or any other directory in your MATLAB path. If you copy the files as part of a folder, then the folder must be included in your MATLAB path for MATLAB to find the autotune function.

The pitch shifting code is a slight modification of the “Guitar Pitch Shifter” from this site . Note that while it is open-source, there may be legal issues with redistributing this code. Do so at your own risk. These issues can be avoided by substituting the pitch shifter for your own pitch shifting code, replacing the call to pitchShift() in autotune.m.

Using the program

The autotune function takes in five arguments, X, pMin, pMax, w, and Fs.

X is the input signal, which is a matrix of amplitudes in either mono (one column) or stereo (two columns). This matrix can be extracted from a .wav file with the wavread command in MATLAB.

pMin is the minimum frequency in which we expect to find a peak, and pMax is the maximum, in Hz. We suggest passing in 60 for pMin and 1050 for pMax to cover the human vocal range, but this interval may need to be expanded for other instruments. In general, the narrowest possible interval covering all played notes is preferable, as this grants the greatest chance of correctly detecting the correct note.

w is the width of the window to correct as if it were an individual note. Note that the current version of the code rounds w to the next power of two, for simplicity. Theoretically, higher values of w would result in less distortion, but also poorer time resolution, where the boundaries between notes would be less precise. We found that 256 was a good value for this parameter.

Finally, Fs is the sampling frequency, in Hz, of the input signal X. This value can be obtained as the second return value of the wavread command, and is commonly either 22050 or 44100. Here is an example of the proper MATLAB commands to auto-tune a vocal sample:

[X, Fs] = wavread('path to input file'); % Read input from .wavout = autotune(X, 60, 1050, Fs); % Process signal wavwrite(out, Fs, 'path to output file'); % Write output to .wav

Alternatively, the output can be played from the MATLAB command line with the following command:

soundsc(out, Fs);

Note that the current version of the code compresses stereo input to mono output, and that execution time can be greatly reduced by processing only a portion of the input song. Please enjoy our code, and feel free to modify and improve upon it!

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
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Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
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Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
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s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
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for screen printed electrodes ?
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s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
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Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
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I'm interested in nanotube
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Ramkumar Reply
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Sravani Reply
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preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
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Source:  OpenStax, Auto-tune. OpenStax CNX. Dec 20, 2012 Download for free at http://cnx.org/content/col11474/1.1
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