2.3. Grabador de sonido
2.3. Recording sound played in a PC
Objectives: To learn a procedure to record sound played by different programs in a computer.
Recording sound played in a PC
In a PC, the default recording device is the Microphone. But the mike (el micro) only allows recording sound coming from outside the computer, for example, your voice. In this activity we are going to learn how to record sound played in your own computer. For example, imagine you are watching a youtube video and you want to record the sound to play it whenever you want.
To start doing it, we must first set up (configurar) LLiurex, in order to set the soud card instead of the microphone as the sound input device (dispositivo de entrada).
ACTIVITY 1. CAPTURING A SONG IN INTERNET
This can be easily made using the LLiurex program Control de sonido.
- Open the program selecting Aplicaciones->Herramientas del sistema->configuración del sistema-> sonido
- A window with five tabs (solapas, pestañas) opens. The tab Aplicaciones shows the programs now playing some audio. For example, if you start playing a youtube video, your web browser appears with the name: ALSA PLUG-IN
- Start the web browser Firefox, and open this link http://freemusicarchive.org/ . All the music in this website has no copyright and we can download and use them. The songs are classified by gender Hay miles de canciones clasificadas por genre (genero músical). To avoid waisting your time looking for a song you like, open the song linked below
- Play the song. the playing button is a little black triangle under the song name.
- Open administrador de sonido. In the tab aplicaciones, there must be shown the browser Firefox playing the song (as ALSA Plug-in).
- In the Eixida/Salida tab are shown the physical devices which are playing sound. By default, the output device are the speakers, or the headphones if they are connected.
- Clic in the tab ENTRADA. Here you can set the input device (dispositivo de entrada). The input device is the soud source used for your computer to record audio.
- Finally use the tab Salida/Eixida to select the options dispositivo audio interno and the option sortida estereo analògic/salida estereo anlògica as shown in the image. There are three possible sources of sound input.
- Line in socket. This is the pale blue socket (zócalo), beside the speakers out socket (green). This socket is used to connect an external source of sound like a syntetizer or a radio set.
- Mic socket: the pink socket. It's used to connect the microphone jacket.
- Intern audio device: This is the sound produced by the software running in the computer and unlike the line in and mic, it doesn't need a physical socket. For example the sound produced by a youtube video played in the browser. As we want to record a song from internetwe must select this device as input sound device.
To record the song wer are going to use Audacity
- Start Audacity
- Press the record button (the one with the red dot in the center)
- Go back to the web browser and play the song.
- Open the Audacity window again. You will see how the sound is recorded. The evolution of the sound track will be shown in a track.
- Stop the recording. Play the recorded track in Audacity.
- Export the track to MP3. Select Archivo->Exportar, select MP3 in the format drop down menu.
- Look for another song you like
- Record 10 seconds
- Export it to MP3. In the metadata windows fill in the fillds author with your name
- Make an script capture of your desktop and upload it to Moodle
- Upload to Moodle the 10 seconds mp3 using the link CAPTURAR CANCIÓN INTERNET.
ACTIVITAT DOCUMENTARY PODCAST
Let's make a short spoken documentary about the Marx brother's. The objective is to make up an audio piece, puting together a voice reading some short texts mixed with some famous short clips of the Marx brother's movies, and a background music.
- Download the mp3 files you are going to need in order to carry out this exercise. Copy to your browser this line, and download the file. Then extract the compressed file to get the sound clips needed
- Instead of using the microhone, we are going to let an Internet robot to read the short texts. Open the page http://www.lumenvox.com/
- By default the robot is Amy, who reads in british english. Select the robot Lorena for spanish north american. There is also a male voice, Luis, for spanish north american.
- Press play to listen how the Lumenvox robot reads the default text)
- Write another text and see how Lorena reads it. For example: "Hola esto es una práctica de informática para el instituto de enseñanza secundaria el Cabañal de Valencia"
Both spanish, voices Luis and Lorena, will alternate reading short texts about the Marx's brothers artistic career. Between the speechs we will place some famous short clips from their movies. In the background there must be a song of your choice from http://freemusicarchive.org/ The outcome must be something like the clip podcastMarx.mp4
- First select the soundtrack (banda sonora). Everey student must choose a song (you are suppose to choose something different from your classmates). Capture it as seen in the previous activity and insert it in a track. You need around 2:30 minutes of music.
- Then record the different short text speeches using Ivona in different tracks.
- Capture the Marx brother speeches.
- Move the clips in order to be played in the correct moment.
- Decrease the intensity of the background music while the speakers Lorena, Luis and the Marx brothers are talking
- Leave the sound louder during some seconds between the speeches.
The key to get the work properly done is to modulate correctly the volum of the music. It must gradualy fade out just when a speech is about to start and fade in when it ends.This can be done in a very acurate way using the wrapping tool (herramienta envolvente)
|Starting point. A track with the default volume.
||With the wrapping tool the playing volume can be increased or decreased in a track seccion. Every click yo do on the track creates a white dot which allows to change the geometry of the curbe representing the track volume.
This is the planned script for our documentary.
- Clip 1: Ask Lorena read this text and record it using Audacity Place it after the previous clip interspersing it with some seconds of music.
Los hermanos Marx, (Zeppo, Gummo,Chico, Harpo y Groucho), fueron unos cómicos estadounidenses, originarios de Nueva York.
- Clip 2: Ask Luís read this text and record it using Audacity. Place it after the previous clip interspersing it with some seconds of music.
Cinco de sus películas están incluidas en la lista de las 100 mejores comedias del American Film Institute.
- Clip 3: Ask Lorena read this text and record it using Audacity, Place it after the previous clip interspersing it with some seconds of music.
En los Cuatro Cocos, su primera película, Groucho es el director de un hotel en bancarrota cuya vida se complica enormente con la llegada de dos granujas, Harpo y Chico
- Clip 4:. Import the sound clip Empleados hotel and place it after the previous clip interspersing it with some seconds of music.
- Clip 5: Ask Luís read this text and record it using Audacity. Place it after the previous clip interspersing it with some seconds of music.
Sopa de Ganso (1933) fue su primer gran éxito. Groucho es el delirante presidente de Libertonia un extraño país europeo a punto de entrar en guerra con Sylvania.
- Clip 6. Import the sound clip quitarles hora del almuerzo.mp3 and place it after the previous clip interspersing it with some seconsds of music
- Clip 7. Ask Lorena read this text and record it using Audacity. Place it after the previous clip interspersing it with some seconds of music.
En una noche en la opera el promotor Groucho embarca a las grandes estrellas de la Ópera de Milan con rumbo a Nueva York, apareciendo abordo unos polizones inesperados: Harpo y Chico.
- Clip 8: Ask Luís read this text and record it using Audacity. Place it after the previous clip interspersing it with some seconds of music
Entre los tres revolucionan el barco, organizan un escandalo en Nueva York y convierten la noche del estreno en una locura
- Clip 9 Import the sound clip La parte contratante.mp3
- Clip 10 Ask Lorena read this text and record it using Audacity. Place it after the previous clip interspersed with some seconds of music
La última película de los hermanos Marx (Amor en Conserva) se estrenó en 1949. Después siguieron carreras por separado en el teatro y la televisión durante los años 60 y 70
- Clip 10 Import the sound clip taxistas africanos.mp3 and place it after the previous clip interspersing it with some seconds of music
- Clip 11 Finally import the sound clip bocina harpo.mp3
HOW TO UPLOAD THE ACTIVITY TO MOODLE
Moodle only allows us to upload files of a maximum size of 1Mb. It's very likely that your song weighs at least 3 or 4 Mb. So in oder to upload the file, we might reduce the sampling frequency (frecuencia de muestreo) and split the file in several pieces
* Select a sampling frequency of 16.000hz. The image below shows how to do it.
* Export the first minut to an
mp3 file and upload it to Moodle to the link ACTIVIDAD GROUXORAP
1. To do this follow the next steps:
o Select the first minute in any of the tracks (whatever)
o Select the menu option Edicion->Seleccion->Todas las pistas. This select the first minute in all the tracks
o Select the menu option Archivo->Exportar Seleccion
- Fill up the metadatos window with your name, your course and the year.
o Name the file and export it with mp3 format