Integrating Technology in the Foreign Language Classroom

Incorporating sound in a presentation or WWW page involves preparing the original sound and digitizing it in an appropriate format.  Because we tend to be visually oriented, sound production can be harder to do well than video production, so you'll probably need to spend more time on it than you might think.

Sound fills the air all around us, and our ear is working all the time to filter out unimportant sound from our consciousness so we can pay attention to the important information. This means that we are largely unaware of how much sound surrounds us at all times.  If you concentrate on what you hear, you will find that silence is very hard to find.  A microphone does not have an intelligent filter, so it will pick up everything (depending on how sensitive it is).  By carefully preparing your recording environment, you can eliminate a lot of the background noise that might otherwise spoil your soundtrack.  Getting a clean recording at the outset will mean less work trying to fix problems later.

Your microphone should be suited to your recording equipment and to the sort of recording you are doing. Poor quality equipment or a noisy environment will introduce noise into your recording, interfering with the signal that you are trying to capture. Basically, signal is what you want, noise is the sound you don't want. An omni-directional mic picks up sound from all directions and is good for recording background noise, music from several directions, or several people talking.  A uni-directional mic is pointed at the sound coming from a single source - one speaker, one instrument, etc.  Clip-on mics can do a great job recording individuals in conversations because they are placed so close to the person's mouth, but if you have more than one or two participants, you may need to think about mixing sounds from multiple mics to control different sound levels.  Table mics are nice for several people sitting around a table but will pick up the sound of someone touching or bumping into the table, shuffling papers, etc., so subjects need to take care if you use these.  Microphones that are built into a tape recorder, camcorder or computer tend to pick up machine vibrations from motors (more noise) and are difficult to place close enough to a subject. A long microphone cable may act as an antenna that could pick up static from fluorescent lighting or even a local AM radio station.

If a microphone's specifications include "signal to noise ratio", a high signal to noise ratio will sound best. Another way to improve your microphone's sound is to use a pre-amp (see below).

Sound is made when objects vibrate producing pressure waves that can be picked up by our ears. These waves can be captured when they vibrate the membrane of a microphone and can be re-created by the amplified vibrations of the membrane in a speaker.  If we graph the intensity of this wave or of the motion of the microphone membrane over time, we will get a smooth waveform curve in which the frequency of a sound is the number of peaks per second (Hertz = cycles per second).  The distance between two peaks is the wavelength.  As with most physical properties (e.g. temperature, pressure, velocity, the shape of the groove of an LP), this is an analog signal. In other words, between any two moments in time we might make infinite number of different measurements of intensity, between any two points on the scale there can be an infinite number of different values. Although the graph shown below looks very simple, real waveforms (a graph of intensity/amplitude) can be quite complex because many different frequencies are actually present simultaneously (a spectral graph will show the distribution of frequencies in a sound).
As with any data stored in a computer, we need to represent the analog signal by a digital approximation that we can think of as a series of numbers measuring samples of the height at intervals along the analog curve.  Computers by their nature can only have space for a limited number of measurements (not infinite) and each value can have a precision limited by the space (number of bytes) allotted to each number (Consider the difference in measuring something on a scale of 1 to 10 vs. a scale of 1 to 1000000). In this way, a series of numbers can be used to produce a signal that approximates the original analog signal, but it can never be truly the same. The more numbers you have (sampling rate in kHz - thousands of cycles per second) and the more precise those number are (resolution of each sample in bits), the more closely the digital sound will resemble the original, but the larger your sound files will be. A digital waveform can never be completely smooth. This is how music on a CD or in an mp3 file works.
The advantages of digital recordings are that the sound can be manipulated computationally, there is no degradation from an original to a copy, and the signal can be sent for long distances over telecommunications links without picking up noise. The disadvantage of digital representation is that it is always just an approximation of the real sound (though this approximation may be so close that our ears can't hear the difference).

The sound card in a computer can create sound, process sound from input sources, and send sound to output destinations. A sound recorder may capture sound from a microphone (mic in) or from an audio device (line in).  It is possible to control which source will be used by opening the volume control.  This utility controls the output or playback volume of a number of devices (microphone, line in, CD audio, midi, wave, etc.).

For Playback


For Recording:


Controls in Windows XP are similar.

 


By resetting the options/properties from playback to recording, the input source (mic, line in, CD, midi) may be selected.  If you are recording from a microphone, you may need to check that the mic is selected here, that the mic volume is adequate but not too loud, and, perhaps if needed, that the microphone is boosted (under Advanced properties). You have to play with it to see what works for your current recording conditions.
 

In Windows 7, the microphone levels can also be adjusted.

Pre-Amp: The quality of microphone inputs can vary enormously from one computer to another. If you need better quality recording from a microphone, it may be worth investing in a pre-amplifier that will amplify the microphone input. This gives you more control over strength of the signal that your computer receives. The sound card in your computer probably has a pretty cheap amplifier for the microphone. A pre-amp will do a better job boosting the microphone's signal.



The output from the pre-amp would then be plugged into the computer's line-in jack (rather than the microphone input jack). When using a pre-amp, you may need to be careful of clipping in both the pre-amp and the sound card.

Microphones may be unidirectional (best at capturing sound coming from a single direction) or omnidirectional (captures sound coming from all directions).



Amplified Lavelier mics clipped onto the speaker's clothing have the advantage of getting more of the speaker's voice than background simply because they are close to the speaker.



For quick interactive communication, a simple monophonic mic & earphone are very easy to set up without wasting time.



 

Sound Recorder

One of the oldest ways to make a recording using Windows' built-in tools is to open the entertainment accessory, (start / all programs / accessories / entertainment) Sound Recorder. Click on the red recording dot to begin.  Save the file in .WAV format using File / Save, and be sure to select File / New to begin another recording from scratch.  Under the menu (Edit / Audio Properties / Customize) it is possible to select a particular frequency and resolution other than the old default 22,050 Hz 8 bit mono.  The best frequency and resolution are always a tradeoff between quality and size.  Music is more demanding than voice. We recommend using at least 22,000 Hz 16 bit for voice recording for projects in this class. However, we absolutely do NOT recommend using Sound Recorder at all! You can download free software that is infinitely better.

Sound Recorder from Windows 7

  

Sound Recorder from Windows XP	AU Samples
	44,000 Hz  16 bit 110 KB	44,000 Hz  8 bit 90 KB
	22,000 Hz  16 bit 61 KB	22,000 Hz  8 bit 45 KB
	8,000 Hz  16 bit 16 KB	8,000 Hz  8 bit 13 KB

A much greater degree of control and more extensive features for manipulating sound files are available in sophisticated sound applications Adobe Audition, and Sound Forge.  The main features needed are selecting and cropping a sound as you might a photo, normalizing a sound as you might adjust the brightness of a photo, and saving the sound in a variety of formats commonly supported by multimedia applications and Web browsers.

 

The Edit / Trim menu will crop (or trim) a selected portion of the sound.  File / Save as... offers a wide variety of options including .AU .WAV, .RA (RealAudio), and .Mp3. Mp3 format is widely accessible and uses an excellent compression CODEC (compression-decompression) to make file size smaller while maintaining very good sound quality.

Audacity

Audacity is a good quality, free sound editing program that has all the features you are likely to need. http://audacity.sourceforge.net/

 

Sound editing will be covered in a later lesson.

There are also other low cost programs available for sound editing that will do a fine job for most of your needs.

Recording Tutorial:
http://www.nch.com.au/kb/10010.html

AUDIO RECORDING AND EDITING FOR THE WEB AND IPODS:
http://people.bridgewater.edu/~rbowman/acadcomp/AudioRecording-print.html

Equipment for Audio Recording of Speech:
http://www.phon.ucl.ac.uk/resource/audio/recording.html

Audacity 2.0 Manual
http://manual.audacityteam.org/o/

Audio Basics from Audacity: Tutorials
Editing and existing file: http://manual.audacityteam.org/o/man/tutorial_editing_an_existing_file.html
Your first recording: http://manual.audacityteam.org/o/man/tutorial_your_first_recording.html

Audacity Tutorial for Podcasts
http://www.how-to-podcast-tutorial.com/17-audacity-tutorial.htm

Sound Advice: 10 Tips for Better Audio Gathering:
http://www.videomaker.com/article/9426/

Sensitivity of the Human Ear:
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/earsens.html

Sound recording: Microphones:
http://www.hrelp.org/archive/advice/microphones.html

A Primer on Microphone Preamps:
http://www.tweakheadz.com/microphone_preamps.htm

Record Your Own Radio Documentary:
http://www.soundportraits.org/education/how_to_record/

How to Create Your Own Podcast - A Step-by-Step Tutorial
http://radio.about.com/od/createyourownpodcast/ss/How-to-Create-Your-Own-Podcast-Make-Your-Own-Talk-Show-Music-Program-or-Audio-Stream.htm