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Algorithm For Identifying the Notes

Step 1: Convert the music segment into frequency domain

Because our recorded music files are chopped into fixed finite length segments, all we have to do is apply DFT to the sample. Considering speed of computation, we decided to use the method of computing with the DFT matrix .

We know that DFT samples are defined by

,

Where

Thus can be expressed in matrix form as

Where

By using the matrix method to compute the DFT, we can calculate the DFT of many pieces of same length and same sample rate music segments at the same time using the same matrix. This will increase the overall speed of our program and enable tune identification for lengthy music that consists of thousands of segments to be analyzed.

Step 2: Find the peaks in the frequency domain representation of the segmented music. Identify the peaks whose frequencies are near integer multiples of each other and group them into the same category.

We know that notes played by instruments have harmonics which the frequencies are integer multiples of the base frequency. Often the note that’s being played is the base frequency or the first odd harmonic of the base frequency. Thus, peaks which frequencies are near integer multiples of each other indicate that they are mostly likely to be the harmonics of a base frequency and the note that’s being played lies within it.

To identify the harmonics we used findpeaks function in Matlab and grouped them in a matrix which the i-jth entry is the frequency of the jth peak over the frequency of the ith peak. We then look for near integer entries in the matrix to determine peaks whose frequencies have integer multiples relationship and categorize them together. The peak with the lowest frequency in each category is the base band while the other peaks in the same category are its harmonics.

Step3: Use the power of peaks to determine the most significant categories.

Because there may be noise and other random vibrations when an instrument is played, there are categories which do not contain the note that’s played by the instrument. On the other hand, when multiple notes are played at the same time (aka a chord), there may be multiple categories which contain notes that are played. To correctly analyze the notes that are being played, we pick out the category which has the most power and categories whose powers are larger than one-tenth of that. The way we calculated the power of each category is by summing up the power(frequency*peak^2) of all the harmonics in that category. After this process, ambient noise and vibrations should be excluded and the remaining categories should contain the notes that are being played.

Step 4: Determine the notes that lie in each category.

Mostly, the base frequency of each category is the note that’s played by the instrument. However, we’ve learned that the note played by some instruments is either the base frequency or the first odd harmonic of the base frequency. To determine which note is being played, we compared the sum of the power of odd harmonics versus the sum of the power of the even harmonics in each category. When the power of even harmonics is larger than a certain times of the power of the odd harmonics, we say that the note is the base frequency; otherwise, we say that the note is the first odd harmonic of the base frequency.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Tune identification. OpenStax CNX. Dec 20, 2011 Download for free at http://cnx.org/content/col11399/1.1
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