<< Chapter < Page Chapter >> Page >

The subVI requires the single indicator (output) envelope , an array with values in the range 0 to 1.

Show that your ADSR VI functions properly by plotting the envelope for at least two distinct cases. Plot both the dB form of the envelope as well as its non-dB form.

The following screencast video provides coding tips and other suggestions to help you develop your subVI.

[video] Coding tips and suggestions for ADSR.vi

Part 2: sound generator

Make a subVI called SoundGen.vi that combines a signal source with the ADSR envelope generator. Use a case structure with an enumerated data type control that allows you to choose one of several different "voices" or "instruments." The case structure then defines the ADSR input parameters to choose the type of signal source (or noise source for a percussive instrument).

The subVI requires the following controls as input parameters (units specified in brackets):

  • duration [s] - total duration of note
  • fs [Hz] - system-wide sampling frequency
  • fref [Hz] - reference frequency
  • note - note frequency as described by an integer value that denotes the number of semitone intervals from the reference frequency; note can be a negative, zero, or positive value
  • instrument - enumerated data type with values of your choice; your SoundGen.vi should have at least three different tone-type sounds and at least two different percussive sounds. Use a variety of envelope shapes.

If the discussion in Item 4 for the note control seems mysterious, review the module [INSERT NAME AND MODULE LINK] to learn how to calculate the frequency of a semitone interval using equal temperament .

Show that your sound generator VI functions properly by developing a top-level VI that plays a chromatic scale. Vary the duration of the notes. Plot the waveform to ensure that the envelope shape makes sense. Save your generated sound to a .wav file to be included with your deliverables.

The screencast video of offers coding tips and other suggestions to help you develop your subVI.

[video] Coding tips and suggestions for SoundGen.vi

Part 3: multi-voice composition

Compose a simple piece of music using analog synthesis techniques of your choice. Better compositions will include variety, e.g., different envelope parameters at different times, multiple channels (chords), stereo, percussive sounds, and so on. Write a paragraph or two that describes your compositional technique. Better compositions are click-free, i.e., joining the notes together does not produce any pops or clicks.

    Hints:

  • You may wish to use a familiar melody (remember, you've got an equation that converts a note from the equal-tempered scale into frequency), or you may want to use a musical "experiment" based on an algorithm as the basis for your composition.
  • Operate multiple instances of SoundGen.vi in parallel (each with a different instrument setting) and add their outputs together.
  • Import multiple spreadsheets to define your note lists (use "File IO | Read Spreadsheet"). Spreadsheets are the easiest way to hand-edit the contents of arrays.
  • Remember to normalize your finished output before saving it to a .wav file. Use QuickScale ("Signal Processing | Signal Operation | Quick Scale") for this purpose.
  • View your finished composition as a waveform plot. Confirm that the envelope shapes make sense, that the waveform is symmetrical about the zero axis (it should not contain any constant offset), and that the waveform fits within the +/- 1 range.

Alternative part 3: multi-voice composition using midi file

The overall objectives of this alternative Part 3 are the same as described above, but the technical approach is different.

Go to MIDI JamSession to learn all about a LabVIEW application VI of the same name that reads a standard MIDI file (.mid format) and renders it to an audio file (.wav format) using "instrument" subVIs of your own design. You have already done all of the work necessary to create your own instruments, and it is a simple matter to place them inside a standard subVI wrapper (or "Virtual Musical Instrument," VMI) that MIDI JamSession can use.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Musical signal processing with labview (all modules). OpenStax CNX. Jan 05, 2010 Download for free at http://cnx.org/content/col10507/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Musical signal processing with labview (all modules)' conversation and receive update notifications?

Ask