# 0.10 Jbs2060-a player piano simulator  (Page 13/17)

 Page 13 / 17

Listing 22 shows a for loop that is used to compute the amplitude at the current time in the current sample including the possibility oftwo or more keys being pressed. When two or more keys are pressed simultaneously, the amplitude of the output is computed as the sum of theamplitudes of the individual keys. This code shouldn't require an explanation beyond that provided by the embedded comments. Note that the name of the key isused to extract the frequency for that key from the Hashtable object that was created by the method named getPiano that was called in Listing 19 .

Listing 22 . Process each piano key that is pressed.
```for(int element = 1;element<array.length;element++){ //Iterate on the piano keys defined in the array.//Get the name of the next key and make sure that it is upper-case. String noteName = array[element].toUpperCase(); try{//Use the noteName and get the corresponding frequency from the // hashtable. Note that results are retrieved from the list as// type Object and must be cast to the correct type. freq = (double)piano.get(noteName);}catch(java.lang.NullPointerException ex){ ex.printStackTrace();System.out.println("noteName: " + noteName); }//end catch//Compute the amplitude for this note at this time and add it to// the sum unless it is a musical rest. if(!noteName.equals("X")){//This is not a musical rest. sum += Math.cos(2*Math.PI*(freq)*time);}//end if //Go back to the top of the loop and get the next key from the// array, if any. }//end for loop```

## Use a scale factor to shape the note

If you press a key on some electronic keyboards and hold the key down, the sound intensity will remain constant with time. However, if you press a pianokey and hold it down, the sound intensity decreases over time. The code in Listing 23 attempts to achieve that same effect.

Listing 23 . Use a scale factor to shape the note.
```scaleFactor = gain*((beats*audioParams.sampleRate/beatsPerSec) - cnt) /(beats*audioParams.sampleRate/beatsPerSec);//Scale the amplitude value and put it into the output array. byteBuffer.putShort((short)(scaleFactor*sum));//Go back and compute the next sample values for this set of keys // until the note duration is satisfied.}//end for loop //Go back, retrieve, and process the next set of keys for a given// duration value. }//end while}//end makeMusic method```

At this point in the creation of the audio sample, the amplitude values for all the keys that were pressed simultaneously have been added together.The resulting amplitude value is scaled so that each note has a maximum amplitude at the beginning and a zero amplitude when the duration has expired. Alinear scale factor is used to accomplish this.

The remaining code in Listing 23 shouldn't require an explanation.

Listing 23 ends the for loop that began in Listing 21 , ends the while loop that began in Listing 20 , and signals the end of the makeMusic method.

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
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
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
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
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?
what is a peer
What is meant by 'nano scale'?
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 ?
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?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
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
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!