Without Les Paul I wouldn’t be an E-Learning Professional

Les Paul, inventor, guitar legend and sound engineering genius died yesterday.

While most of the tributes to this most rounded of individuals rightly focus on his contribution to music, both through his virtuosity on the guitar and his invention of his eponymous Gibson instrument. I'd like you to consider this: if you work in e-learning or digital media content development you probably wouldn't have a job without Les Paul’s influence and inventions.

Why?

He invented multitrack sound recording.

Multitrack recording (also known as multitracking for short) is a method of sound recording that allows for separate recording of multiple sound sources to create a cohesive whole. Today, this is the most common method of recording popular music, radio documentaries, and podcasts. Back in the day, I learned to record sound to magnetic tape (including the black art of editing sound by physically splicing bits of tape together), before moving to DAT, mini-disc, and finally recording and editing audio in a purely digital environment about 10 years ago.

Today, I use multitracked audio to create podcasts for distribution on the web and via iTunes, demos, simulations, training videos, and a host of other learning applications.

All of these developments occurred because of Les Paul's innovations in multitracking 60 years ago. He was so influential that modern digital audio editors (and digital media editing tools like Adobe Premiere and Techsmith Camtasia) still use the multi-channel / multi-track timeline user interface paradigm, and still sport controls for cutting, splicing, and cross-fading the content stream, same as in the physical magnetic tape editing I used to do many years ago.

Source audio for a podcast in a digital multitrack editor

"Big deal" I hear you say, "if he hadn't done it, someone else would have."

Maybe, but he did it. And it was his musical artistry and fame as a recording artist (with his then-wife Mary Ford) that popularized the technology in a way no 'man in a white coat' could ever have.

So thanks for the music, Les, and the guitar.

And the career. Requiescat in pace.

Les Paul (1915-2009)

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Podcasting for E-Learning: Digital Audio Basics

Really exceptional podcasts transmit a sense of "being there."

Well-designed, planned, narrated and produced audio content has the facility to engage the audience and transport the listener, providing the right cognitive environment for learning or entertainment or whatever goal the podcast seeks to achieve. As the old story goes, “there are better pictures on the radio.” Denis Nowlan, Deputy to the Controller for BBC Radio 4 describes this as

the wonder of radio [and sound] …the conjuring of magical sounds, Prospero-like, out of the silently teeming air. And the sense of joining, instantly, with a vast community of listeners.

(2005)

Of course, this cognitively experienced sense of “being there” is a completely artificial construct, none more so when you consider audio podcasting. The journey the podcaster takes us on is based on nothing in nature; that is, a narrative transmitted as binary data: electronically-mediated zeros and ones.

I will discuss this phenomenon in detail next time, but for now, read on…

Digital audio is actually very similar in concept to motion film, where a rapid series of still photographs make up a “motion picture.” Digital recording reproduces audio signals by taking many still “pictures” – or samples - of an audio waveform and then reconstructing the waveform for playback digitally (see Figure 1).

Figure 1. Digital Sampling of Audio Waveform
[Click to Enlarge]

In film, the number of still images (frames) we move through the projector per second improves the smoothness and quality of picture we see. Similarly, the size of the film's light-sensitive crystals in each frame determines the visual resolution of the image - and we all know movies look better in 70mm as opposed to the 35mm or 16mm film.

In digital audio, an analog signal is typically sampled 44,100 times a second. Each sample is created by taking a "snapshot" of the amplitude (or strength) of an analog audio signal at a particular moment in time. and converting that amplitude into a binary number.

The number of samples contained in each second of audio is called the sample rate. The greater the number of samples per second, the greater the resolution of the audio signal.

Let’s return to the film analogy: the faster the film rate through the camera, the better the ability of the film to pick up motion. For example, if you crank a film camera too slowly, then motion past a camera is not smooth since the frame rate does not capture enough frames in a given amount of time to stop the motion from appearing to jump or jerk - too much action happens in front of the camera "between frames" for the motion to appear natural.

Time for an example: The resolution of an audio CD is 16 bits and the sample rate is 44.1KHz. This means that the audio is sampled 44,100 times a second and a series of 16 zeros and ones is used to define the amplitude of the waveform at each of those 44,100 points.

This resolution – commonly called “CD Quality” and should be your baseline for recording a podcast. When recording voice-over narration, capture all of your audio at 16 bit, 44.1KHz, in mono using the WAV format in Windows, Au format for Unix-based systems (like Linux), and AIFF for Apple Mac.

More...

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References:

Nowlan, D. (2005). Radio: where the pictures are better: Denis Nowlan speaks for the medium which leads you by the ear. [Internet] Available from: http://findarticles.com/p/articles/mi_m0KZH/is_1_19/ai_n15928065/ Accessed 12 August 2009.

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Podcasting for E-Learning: Introduction to Audio Production

Having outlined the conceptual terrain of podcasting, it's time to look at the nuts and bolts of podcast production. In this part of the series, I won't delve too deeply into script-writing: I'll return to that subject in a later series of blog posts, but if you have a look at my series of articles on instructional design to understand my orientation on theoretical and pedagogical approaches to this activity.

Today, I'm going to talk about digital audio, and the basic hardware and software you'll need to begin creating your own podcasts. As I indicated yesterday, the principles of multimedia have been understood for over 80 years, but wide usage of digitally factored technology did not begin in earnest until the 1970’s, because theory had to wait for hardware and software to catch up.

Until recently, recording audio cost many thousands of dollars, used specialized and sophisticated equipment, took up lots of space (in the form of a dedicated recording studio), and required years of specialized training, followed by years acquiring hard-earned OTJ experience to make even the most basic recordings.

In the last five years however, the price of recording audio has gone down, while the quality of consumer recording devices has increased exponentially. Now, it’s even possible to create and deliver reasonable quality audio via your cell phone with a Edge connection to the internet. But we’re not going to do that today. Today, I will describe the essential hardware and software you’ll need to begin recording and producing good quality audio for integration for podcasting and e-learning.

You will need…

Activity	Requirement
Audio source	A Narrator
Capture	A Microphone
Encoding	Audio editing software Audacity Sound Forge WaveLab GarageBand
Recording Medium	Audio Tape (i.e. DAT) or PC Hard Drive
Playback	Playback Device PC Laptop PDA Cell Phone Portable Media Player Speakers Headphones

And this is the audio production process (see Figure 1).

Figure 1. The Audio Production Process
[Click to Enlarge, 145k]

Production Step	Component	Process Description
Audio Source	Voice–over narrator	Reads script based on objectives of learning initiative
Recording Device	Microphone	Captures analog sound waves and coverts to electronic signal
Conversion	PC soundcard	Turns electronic signal into a series of digital bits
Encoding	Audio Editing Software	Software saves the audio as a sound file (i.e. WAV)
Editing	Audio Editing Software	The audio file is edited, & enhanced. It is rendered in a playback-friendly format like MP3
Distribution	LAN, internet, CD, DVD, memory card	Content is published for distribution via the Web as an audio only file (i.e. podcast), in a format like Flash, or for delivery via CD/DVD, memory stick
Playback	Soundcard, Speakers, Headphones	Media is reproduced via software or hardware player

More...

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Podcasting for E-Learning – Storytelling and Teaching

Sound – especially the human voice - has been a fundamental part of the transmission of information and knowledge since pre-history.

In Western culture, for example, the oral tradition – story telling – was the primary means of passing on the learned, shared values of culture, encoded in legends, myths, and fables until the invention of writing. We still have these stories today – Homer’s Iliad and Odyssey are two examples well-known examples. Significantly, these texts begin with the words “Tell us…” and “Sing to me…” respectively, demonstrating their origins as stories told to audiences.

Half a millennium later the philosopher Plato, founder of the Academy in Athens - the first institution of higher learning in the Western world - chose to render the teachings of his mentor Socrates as a series of dialogs.

We can all think of great orators. Consider Winston Churchill’s speeches in WW2

Never in the field of human conflict was so much owed by so many to so few.

In this 40th anniversary year of the Apollo 11 Moon landing, think too of JFK’s 1962 speech:

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard…

A few years later, Martin Luther King inspired a nation with his immortal phrase:

I have a dream.

Only a few months ago, Barak Obama popularized the slogan "Yes we can" during his 2008 US presidential campaign.

We can say then, that audio has be a core component of teaching for at least 3000 years. The problem with sound though, that it is ephemeral – it is not permanent – once spoken, the words are gone forever. Until the later 19th Century, transcription was the only way to capture spoken words permanently.

This all changed in the late 19th Century, when the basic components of what we know today as multimedia were invented.

In 1876 Alexander Graham Bell patented the telephone. One year later, Thomas Edison’s invented the phonograph. These devices enabled the mechanical recording and reproduction of audio, such as spoken voice, singing, instrumental music, or sound effects for the first time in history. In 1878, the first motion-based pictures were filmed in England.

So within three years of each other, mechanically recorded audio and video, supported by an electronic transmission infrastructure were invented, and elements are still the core elements of recording, reproducing, and distributing media content.

Next time: Digital audio and podcasting for e-learning

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New E-Learning Curve’s Other Podcast episode release:

In Part 5 of Transatlantic: The Flying Boats of Foynes

Part 5: Foynes goes to War

Appeasement has failed. On September 3rd 1939 Britain and her allies declare war on Germany after the Invasion of Poland. In neutral Ireland, the government initiates a state of emergency, an official euphemism used by the Irish Government during the 1940s to refer to its position during World War II. The flying boat service In the west coast town of Foynes in County Limerick. Rationing is introduced, but the influx of passengers and cargo ensures that this town on the River Shannon has it a little easier than the rest of the country…

Click here to listen to the podcast.

Click here to view the transcript of this podcast (PDF, 24K).

Even though this is an e-learning blog, the observant among you will notice that the podcast isn’t about e-learning. That’s OK – the point of e-learning is to provide training professionals with a means of creating and distributing content that enables people to acquire information, knowledge, skills, and expertise on a diverse range of subjects: as e-learning practitioners, it’s our job to facilitate this process.

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