Integrating Technology in the Second Language Classroom

Incorporating sound in a presentation, and activity or Web 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 image 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/brain 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.  Capturing 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 sounds, 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 (some of the recordings might be louder than others).  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. Boom mics can help avoid noise from objects.  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. Digital recorders help avoid this problem because they have no moving parts. A too long microphone cable may act as an antenna that could pick up static from fluorescent lighting or even the signal from 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 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 could potentially make an 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 and overlap 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. (We saw this with images, and the same is true of sound.)  Computers by their nature can only have space for a limited number of measurements (not infinite) so 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 or bytes), 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. (IOW The numbers don't change.)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 really can't hear the difference).

The sound circuits 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, you might need to try different sound input ports to be sure you have one that works well with your microphone. These might be on the front or the rear of the computer or may be at the back of a sound card or even in a USB port or webcam. One of these selections can be set as the default recording source in the Recording Devices property such as this tab in Windows 7/8/10. If you are using a program such as Audacity, you can select one of the recording (input) devices directly in the program.


 

In Windows 7 or 8 or 10, the microphone levels will likely need to be adjusted through the microphone properties. You may have to tweak the settings (sound levels) in the microphone properties tab (Microphone boost and Microphone level) to find the level that works best for your devices and environment.

Note that if you are trying to adjust the levels but you are still not getting any sound, you might be adjusting the wrong microphone!

Note that you can also record the sound being played by your computer (for instance rom an online radio program). For this you need to enable the Stereo Mix frature in your sound recorgind options.

https://www.howtogeek.com/217348/how-to-record-the-sound-coming-from-your-pc-even-without-stereo-mix/

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 decent pre-amp will do a better job boosting the microphone's signal. This is likely to be overkill for most applications.



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 computer sound input.

Microphones may be unidirectional (best at capturing sound coming from a single direction) or omnidirectional (captures sound coming from all directions). Microphones can also be mono or stereo. Plugging a mono microphone into a steeo jack may result in unwanted noise on one of the channels.



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. A good option for wireless Lavelier mics is the Audio-Technica ATR288W. These work great of the subject might be moving around.



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



 

USB sound recording devices

Some microphones connect to the computer using a USB connection. Since USB is digital, the quality of the sound will depend only on the quality of the USB microphone. Some more expensive USB microphones such as the Blue Yeti have high quality analog to digital conversion, multiple configurations (stereo, omni-directional, cartoid, figure 8, and built-in monitor jacks. USB Webcams usually also have built-in microphones; so you could also use your webcam as a microphone. Their quality varies considerably.

 

Other personal recording devices

Most people already have a variety of devices that might be capable of recording sound. Your voice recorder, iPod, mp3 player, or cell phone, especially a smart phone with a voice recording app can be used to capture sound and then transfer it to your computer. Get to know your own device. Where are the sound files located? What format is used (WMA, M4A, MP3)? How can you transfer them easily to your computer? Make sure that your sound editor is configured to edit your sounds and save them as mp3.

 

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

	Samples
	44kHz, 16bit, 110 KB	44kHz, 8bit, 90 KB
	22kHz, 16bit, 61 KB	22kHz, 8bit, 45 KB
	8kHz, 16bit, 16 KB	8kHz, 8bit, 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.

There's an App for that.

Your cell phone could be used for this function as well. There are lots of free sound recorders that turn your cell phone into a digital voice recorder. One example is Hi-Q MP3 that has lots of useful features. Paired with a utility like AirDroid that provides wireless file transfer between phone and computer over the Internet, or by using utilities such as Google Drive to transfer the files wirelessly, one can quickly capture audio without any significant setup time or need to configure the computer microphone properties. The sounds can then be transferred to your computer without having to connect a wire.

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

Audacity Tutorial for Podcasts
http://www.howtopodcasttutorial.com/17-audacity-tutorial.htm

Sound Advice: 10 Tips for Better Audio Gathering:
https://www.videomaker.com/article/c4/9426-sound-advice-10-tips-for-better-audio-gathering

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

How to Create Your Own Podcast - A Step-by-Step Tutorial
https://www.thoughtco.com/how-to-create-your-own-podcast-2843321

HOW TO MAKE A SUCCESSFUL PODCAST
https://www.digitaltrends.com/how-to/how-to-make-a-podcast/2/

Call Recording - Record a guest for your class over the phone
https://www.tapeacall.com/blog/make-podcasting-easy-with-iphone-and-android-call-recording/