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An individual who can whistle with vibrato can be well-modeled by a sinusoidal oscillator, an attack-sustain-release envelope with a moderate attack and release time, and a low-frequency sinusoidal frequency modulation. In this mini-project you will develop code to model the whistler as a LabVIEW "virtual musical instrument" (VMI) to be "played" by a MIDI file.
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


An individual who can whistle with vibrato can be well-modeled by a sinusoidal oscillator, an attack-sustain-release envelope with a moderate attack and release time, and a low-frequency sinusoidal frequency modulation. In this mini-project you will develop code to model the whistler as a LabVIEW virtual musical instrument ( VMI ) to be "played" by a MIDI file.

Prerequisite modules

If you have not done so already, please study the pre-requisite module Vibrato Effect . If you are relatively new to LabVIEW, consider taking the course LabVIEW Techniques for Audio Signal Processing which provides the foundation you need to complete this mini-project activity, including working with arrays, creating subVIs,playing an array to the soundcard, and saving an array as a .wav sound file.


  • All LabVIEW code that you develop (block diagrams and front panels)
  • All generated sounds in .wav format
  • Any plots or diagrams requested
  • Summary write-up of your results

Part 1: tone generator with vibrato

In this part you will create a basic tone generator with vibrato. The tone generator will be a sinusoid of the form y ( t ) = sin ( ϕ ( t ) ) , where the phase function ϕ ( t ) has the following form ( ):

ϕ ( t ) = 2 π f 0 t + Δ f sin ( 2 π f R t )

where f 0 is the tone frequency, Δ f is the frequency deviation (vibrato depth), and f R is the vibrato rate in Hz. Use the "Play Waveform" Express VI to listen to your end result y ( t ) , and experiment with the parameters to find suitable values for rate and depth to simulate the sound of a whistler. Refer to the screencast video in the module Frequency Modulation (FM) Techniques in LabVIEW for coding tips for this part.

Part 2: attack-sustain-release envelope generator

Create LabVIEW code to generate a time-varying intensity envelope for the overall attack, sustain, and decay of the note. Your code will require attack time and decay time (both in seconds), as well as the total number of required samples, and will produce an envelope composed of three straight-line segments as plotted in .

Attack-Sustain-Release envelope

The maximum intensity is fixed at 0 dB, and the minimum intensity is -40 dB. The attack and release times are fixed parameters that you adjust, and the sustain time is "stretchable" depending on the total number of required samples. If you have the inclination, make your envelope generator more robust so that it can handle the situation where the requested number of samples is less than the number of samples required for your attack and release intervals.

Part 3: attenuator

Create LabVIEW code that accepts an "amplitude" parameter in the range 0 to 1 and converts this parameter to attenuation in the range -40 dB to 0 dB. The amplitude parameter will ultimately be supplied by MIDI_JamSession and represents the MIDI "note-on" velocity. Your code will map linear velocity onto a logarithmic intensity.

Part 4: overall amplitude envelope

Combine the code fragments you developed in Parts 2 and 3 to create an overall intensity envelope. Remember that when you use intensity values in decibels, you simply add them together. Next, "undo" the equation for decibels to convert the intensity envelope into an amplitude envelope (hint: you need a value of "20" someplace). Choose a representative set of parameter values and plot your overall intensity envelope and your overall amplitude envelope.

Part 5: whistler vmi

Design a virtual musical instrument ( VMI for short) that sounds like someone whistling with vibrato. Your VMI will be played by "MIDI Jam Session." If necessary, visit MIDI Jam Session , download the application VI .zip file, and view the screencast video in that module to learn more about the application and how to create an instrument subVI, or VMI. Your VMI will accept parameters that specify frequency, amplitude, and length of a single note, and will produce an array of audio samples corresponding to a single note. Use the tone generator you developed in Part 1, and apply the amplitude envelope you generated in Part 4. You may wish to keep all of your parameters as front-panel controls and add the "Play Waveform" Express VI to listen to your VMI during development. Adjust the parameters to obtain pleasing and realistic settings, then convert the front-panel controls to constants and remove "Play Waveform." Your finished VMI must not contain any front panel controls or indicators beyond those provided in the prototype instrument.Choose a suitable MIDI file and use MIDI_JamSession to play your whistler VMI. MIDI files that contain a solo instrument, slow tempo, and long sustained notes likely produce better results, for example, Johann Pachelbel's "Canon in D." Try Pachelbel_Canon_in_D.mid at the Classical Guitar MIDI Archives . You can also find a more extensive collection at ClassicalArchives.com , specifically Pachelbel MIDI files . Create a .wav file of your finished work.

Optional: modifications to basic whistler vmi

Following are some suggested modifications you could try for your basic whistler VMI:

  • Make the vibrato rate proportional to the intensity envelope. This characteristic is common for vocalists and many types of instrumentalists.
  • Make the vibrato depth proportional to the intensity envelope. This is another characteristic common for vocalists and many types of instrumentalists.
  • Vary either the vibrato rate or depth (or possibly both) according to the "amplitude" parameter provided by the prototype VMI. For example, higher amplitudes could be mapped to a faster rate or more depth.
  • Duplicate the tone generator two more times with frequencies of 2 f 0 and 3 f 0 and intensities of -10 dB and -20 dB, respectively, to create some overtones. Each of the tone generators should have the same vibrato rate and depth. The overtones make the whistler sound a bit more like a flute or a singing voice.

Questions & Answers

are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
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..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
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.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Musical signal processing with labview -- tremolo and vibrato effects (low-frequency modulation). OpenStax CNX. Nov 07, 2007 Download for free at http://cnx.org/content/col10482/1.1
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