Instruction manual - Pizzicato 3.6.2 | EN900 - Revision of 2013/05/29 |
Audio tracks
Subjects covered:
Audio or MIDI? [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
Up to now, we have only used MIDI to manipulate music and hear the notes. Pizzicato plays the score by creating a series of MIDI events. The sound card of your computer or your external synthesizer uses those MIDI events and transforms them into a real sound that you can hear through the speakers. This working method is quite satisfactory in many cases. Most music information can be indeed represented by a sequence of MIDI events.
However, there are cases where MIDI can not be used. For instance, if you want to add your voice to a music arrangement, or if you want to play a real instrument and record the exact way it sounds, MIDI is of no use. In that case, the program must record and store the sound itself (or at least its mathematical representation).
As we have seen in a previous lesson (see the "Music notation" lesson), a sound is simply a vibration of air. It has four main qualities: the pitch, the amplitude, the timber and the duration. When an acoustic instrument plays, it vibrates at certain frequencies and transmits that vibration to the air around it. This vibration finally comes to your ear and you get the sensation of sound, with its various qualities.
To record sound, we need to measure the position of a particle of air, around its central position, so that we can thereafter reproduce the same vibration. For practical purpose, we can say that the zero value will represent the position of a particle of air when no sound travels through it. If the particle is pushed forward, we can measure its displacement from its central position and write it down. Such a measure is called a sample.
As the vibrations of sound are quite fast, we must do so a lot of times per second. In fact, as the human ear can only perceive up to about 20 to 22 thousands vibrations per second, there is a mathematical principle that tells us that we must measure the air position at least two times that frequency, so that the sound is recorded and stored accurately. This is the reason why, on a music CD, the frequency has been fixed to 44100 samples per second. This frequency is also called the sample rate and is expressed in Hertz (abbreviation Hz) which means "vibrations per second".
If we record a sound with a much lower sample rate, a part of its vibrations are lost when we reproduce it. Indeed, the information is missing in the record and the sound quality deteriorates. The most common example is a telephone line. In the beginning, they used an 8000 sample rate. As the human voice is not using the full spectrum of sound vibrations, the phone quality was enough to transmit an understandable conversation. But try to listen to a full symphony orchestra through a phone and you will hear that the sound quality is quite poor, indeed.
Another important parameter is the precision with which the position of an air particle is measured. You could measure on a scale that contains 10 positions or 10000 positions or more. If there are too few positions on the scale, there will be an approximation of the position. To give a comparison example, if you measure the dimensions of a room with a meter that do not have any centimeter graduations, you could then say the room is 3 meters or 4 meters, but you could not say exactly 3 meters and 23 centimeters. By transmitting the information that the room is 3 meters, it would not be exact and if an architect creating a big building would use that precision level, there is no doubt that the building would fall apart very soon. So the precision is quite important. For the CD quality, a scale has been set that goes from -32768 to +32767. The specificities of those numbers come from the binary system used to encode them. Indeed, 2 to the 16th power equal 65536 so that there are so many possible values to a sample (65536 = 32768 negative values + 32767 positive values + 1 value for zero). So we say that the quality of a CD is in 16 bits (a bit is a BInary digiT).
As a summary, we can say that an audio recording is a series of numbers that represent a sound and that may be used to recreate that sound at any moment through the speakers of a computer. In CD quality, one second of music is represented by 44100 times 2 numbers (because stereo is used, so there are two channels), each one of them being in the range from -32768 to +32767. When we put those numbers on a graph with time, we get a picture like this:
where the upper part is the left channel and the lower part is the right channel. Those curves represent in fact the position of an air particle when this sound is heard. Most software working with audio will represent sound as above.
What is an audio track? [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
An audio track is the representation of a sound for a specific duration. For instance, you could have a track of 4 seconds in duration. By playing this track, you will hear the sounds it contains.
Pizzicato lets you add one audio track (or several with Pizzicato Professional or Composition Pro) to a score. You can specify when the audio track begins, in relation to the score and Pizzicato will play it together with your score.
Each audio track is in fact represented by a wave file (".wav" extension on Windows). There are lots of existing audio file formats. Pizzicato works with WAVE files, as they are very common and can be used on Windows as well as on the Mac. You will find various software format converters on the Internet, so that you can use wave files and then convert them into or from mp3, aiff and many other audio formats.
You should well understand that the audio information is stored in the wave file and not in the Pizzicato document. The Pizzicato document contains a reference to the wave file, so that it can play it at the same time than the score. If you want to send a Pizzicato score containing audio tracks to a friend, do not forget to send also the corresponding audio files. Existing audio files may be inserted in the score, but you can also create an empty audio file and record it yourself, with a microphone.
Adding an audio track [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
Depending on the Pizzicato version you have, you access or add an audio track differently. For most versions, do the following:
- Starting with a new document, select the Associated audio track... item from the Windows menu. The audio track selection dialog appears.
For Pizzicato Professional or Composition, do the following:
- Starting with a new document, open the conductor view (Windows menu, Conductor...).
- Right-click (Alt-click on Mac) on the main score represented by a large rectangle, and select the Add an audio track... item. The audio track selection dialog appears.
The audio track selection dialog appears as follows:
This dialog lets you specify the associated audio wave file. You may either select an existing audio file or create a new one. We will first open an existing audio file.
- Click on the Select... button. A standard dialog box lets you open a wave file. If you do not have such files, you may download wave files from the Internet. On Windows you may also go in the Windows directory, in the Media sub-directory where you will find the various sounds used in Windows. For instance, we have here opened the file named "The Microsoft Sound.wav". The Quality and Duration frames now display the specification of the file:
It is an 8 bits, mono, audio file, with a sample rate of 22050 samples per second and its duration is 6 seconds and 122 milliseconds.
- The left frame with the Start in score label specifies the starting point of this audio file in relation to the score. By default, it starts at measure 1, beat 1 with no additional delay. The Unit label specifies a number of units where one quarter note is the equivalent of 480 units. So if you want the file to start on the first half beat, you would specify 240 units.
- In the lower part of the dialog, two sliders specify the volume with which the sound file will be played, for the left and right channels.
- Click on the OK button. For Pizzicato Light and Beginner, the audio editor appears. Just close that window for the moment.
- You may add some notes on the score and Pizzicato will play both the score and the audio file that you just added.
You may also create a new audio file and associate it with the score.
- Close this document without saving and create a new one. Then call the same dialog as above.
- You may specify the quality and duration of the audio file you want to create. By default, the quality is the best (CD quality) and the duration is 10 seconds. Click on the Create... button.
- A file dialog opens so that you can specify the file name and location. You may in fact create the audio file in any directory you want, not necessarily in the same directory as the Pizzicato file. A reference to that directory will be saved with the Pizzicato file.
- This audio file is created with nothing in it but a silence of 10 seconds. We will be able to record it with the audio editor in the next lesson.
The Delete button is used mainly for the Pizzicato versions with one audio track. Clicking on it just removes the reference to the audio file from the Pizzicato score. Notice that the audio file itself is not destroyed.
Multiple audio tracks [Professional] [Composition Pro]
With Pizzicato Professional or Composition Pro, you may add several audio tracks to the same score. You may start the audio tracks at different position in the score. When an audio file has been added, it appears just below the score as a colored band, at the position where it will start to play and with the length showing its duration in relation to the score:
The little icon on the left bottom of the score rectangle shows that this score has associated audio tracks. Clicking on it switches between viewing the audio tracks below the score or not viewing them.
To add another track, just do exactly the same as explained above. In fact, you may add the same file more than once, at various positions in the score. When adding more tracks, the conductor view will display something like this:
For each track, you may specify the starting point in the score as well as the volume of the audio file. The starting point may also be adjusted by directly dragging the yellow bands horizontally. While doing so, there is a magnetic grid that positions the starting point at multiples of half a beat, so as to accurately place the audio file, but you may disable that magnetism by holding down the CTRL key.
When you click with the right mouse button (alt-click on Mac) on an audio track, three menu items appear:
- Edit audio track... is the equivalent of double-clicking the audio track and calls the audio editor. This audio editor is the subject of a specific lesson.
- Audio track properties... calls the dialog that we have seen in this lesson. You can then change the file, create a new file or specify its volume.
- Remove audio track just removes the track. The audio file itself is not destroyed.
Audio setup [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
The audio setup should work correctly by default. You may access it in the Options menu, Audio setup...:
- Interface used: you may select the audio input/output used to play/record audio. By default, the standard input/output are used.
- Sound quality: specifies in which sound quality the sound card will function when working in Pizzicato.
- Audio manager setup: those parameters are technical parameters that Pizzicato uses to play and record audio. You should leave them as they are, except if you experiences difficulties like hearing the sound in a jerky way. On Mac, they are not available, because the audio manager works differently than in Windows. Pizzicato uses audio buffers in a cyclic way. These parameters specify the number of buffers, how many buffers are used together and the size of the buffers, both for output and input.
If you experience a jerky sound, increase the size of the output buffer by steps of 100 until you hear a correct sound. Conversely, to experience the shortest delay possible between the coloring of the note and its sound, try to reduce the output buffer size by steps of 50 or 100. When you close this dialog, you may need to exit and restart Pizzicato for the changes to be taken into account.
The Default values button lets you reset the parameters to their default values.
If you experience a delay between the score (MIDI instruments) and the audio track, you must add the same delay to MIDI, so as to compensate. This is done by the MIDI play options... item of the Options menu. There is a slider named MIDI delay in milliseconds (correction for audio). Adjust its value so that MIDI and audio are played exactly togther.
The ASIO Setup... button will be explained in the next section.
Using an ASIO driver [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
Since version 3.5.2, Pizzicato can work with an ASIO driver to handle audio. ASIO (Audio Stream Input/Output) is a standard protocol to manage a sound card efficiently. It can reduce the latency time, which is the delay between the moment that Pizzicato writes sound data to the card and the moment when you hear it. Many sound cards running on Windows have a latency time that creates a delay that is disturbing when you play on the MIDI keyboard and want to hear the Papelmedia sound library delivered with Pizzicato.
Some sound cards have their own ASIO drivers, but you can always download and install a universal ASIO driver called ASIO4ALL, which is free, on page: http://www.asio4all.com/
If you want to use the ASIO driver with Pizzicato (only on Windows), click the "ASIO setup..." button in the Audio setup dialog (Options menu).
The following dialog appears:
The menu entitled "Select ASIO driver to use" let you choose the driver to use, as you can indeed find several ASIO drivers installed on your computer. Try them all if necessary and check the one that is running fine with Pizzicato (in case of problems if Pizzicato won't start anymore, see the remark at the end of this section).
You have four other menus to select the left and right channels, for ouput and input.
The "ASIO control panel..." button calls a dialog that depends on the ASIO driver. This control panel is used to set up the driver according to the audio hardware you have. The default value should work, but for more details, see the documentation of the ASIO driver or sound card.
If you want to go back to a normal audio setup, without ASIO, click the Do not use the ASIO driver... button and it will display the normal audio setup dialog.
Confirm the ASIO setup by clicking on the OK button.
Warning: Installing and setting up an ASIO driver and making it work with Pizzicato is not always easy, according to the hardware and software you have. In case of problems, it may require technical skills to solve the situation. We cannot here enter into such setup complexities. We have described the basic procedure, that should work in most cases.
If after trying to setup ASIO with Pizzicato, Pizzicato won't start or crashes at startup, here is how to solve the situation. Just remove the following file:
My documents / Pizzicato 3.x / Prefs / Audio.dat
Then start Pizzicato and the default audio setup will be recreated (without ASIO).