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Additive synthesis creates complex sounds by adding together individual sinusoidal signals called "partials." In this module you will learn how to synthesize audio waveforms by designing the frequency and amplitude trajectories of the partials. LabVIEW programming techniques for additive synthesis will also be introduced in two examples.
This module refers to LabVIEW, a software development environment that features a graphical programming language. Please see the LabVIEW QuickStart Guide module for tutorials and documentation that will help you:
• Apply LabVIEW to Audio Signal Processing
• Get started with LabVIEW
• Obtain a fully-functional evaluation edition of LabVIEW

Overview

Additive synthesis creates complex sounds by adding together individual sinusoidal signals called partials . The prerequisite module Additive Synthesis Concepts reviews the main concepts of additive synthesis. In this module you will learn how to synthesize audio waveforms by designing the frequency and amplitude trajectories of the partials. Also, LabVIEW programming techniques for additivesynthesis will be introduced in two examples.

Frequency and amplitude trajectory design

A partial is the fundamental building block of additive synthesis. A partial is a single sinusoidal component whose amplitude and frequency are each time-varying. The time-varying amplitude denoted a ( t ) is called the amplitude trajectory and the time-varying frequency denoted f ( t ) is called the frequency trajectory . Additive synthesis requires the design of both trajectories for each partial; the partials are then summed together to create the sound.

The screencast video of [link] shows how to begin the design of a sound as a spectrogram plot, how to design the amplitude trajectory first as an intensity (loudness) trajectory in "log space" using decibels, and how to design the frequency trajectory in"log space" using octaves. Designing the partials in log space accounts for hearing perception which is logarithmic in both intensity and in frequency; refer to Perception of Sound for a detailed treatment of this subject.

[video] Design of frequency and amplitude trajectories

Example 1: fractal partials

In this first example, partials are created during a fixed time interval and then concatenated to create the overall sound. During the firsttime interval a single partial is created at a reference frequency. During the second time interval the partial's frequency linearly increases in "octave space" from the reference frequency to a frequency two octaves abovethe reference frequency. In the third interval the partial bifurcates into two partials, where one increases by an octave and the other decreases by an octave. In the fourth interval, each of the two partials bifurcates again to make a total offour partials, each increasing or decreasing by half an octave. This behavior repeats in each subsequent time interval, doubling the number of partials, and halving the amount of frequency increase or decrease.

The screencast video of [link] shows how the frequency trajectories are designed in "octave space", and then reviews the key LabVIEWprogramming techniques needed to implement this design. The video also includes an audio demonstration so you can hear the design of this "audible fractal."

The LabVIEW VI demonstrated within the video is available here: genfnc.zip . This VI requires installation of the TripleDisplay front-panel indicator.

[video] Design of the "audible fractal," LabVIEW implementation, and audio demonstration

Example 2: spectrogram art

The design of a sound using additive synthesis typically begins with a spectrogram representation of the desired sound. In this second example, straight line segments define the frequency trajectories of nine distinct partials that create a spectrum of a recognizable object, specifically, a cartoon drawing ofan individual who is happy to be wearing a French beret.

The screencast video of [link] shows how the frequency trajectories are designed in "octave space" and specified according to the coordinates of the line segment endpoints. The design of the corresponding amplitude trajectories necessary to make the partials start and stop at the correct timesis likewise discussed. Key LabVIEW programming techniques needed to implement this design and an audio demonstration are also presented.

The LabVIEW VI demonstrated within the video is available here: face.zip . This VI requires installation of the TripleDisplay front-panel indicator.

[video] Design of the cartoon face, LabVIEW implementation, and audio demonstration

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
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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
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da
Application of nanotechnology in medicine
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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
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Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
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Alexandre
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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'?
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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
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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 ?
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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
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Source:  OpenStax, Musical signal processing with labview -- additive synthesis. OpenStax CNX. Nov 07, 2007 Download for free at http://cnx.org/content/col10479/1.1
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