First posted: Jan 4, 2001
Last update: Jan 14, 2001
Audio for Online (Enhanced) Courses
Taped lectures (or parts thereof) as well as special guides (not unlike
those audio tapes available in some museums and exhibitions) can be a great
added value for online (enhanced) courses -- no matter whether these are
technology enhanced traditional classroom based courses, hybrid courses,
or genuine distance learning courses. As long as a teacher is simply taping
him/herself, there are not even any copyright problems. In case of guest
lectures, of course, proper permission to make and use a recording must
There are two major distribution modes to consider:
Recent technological advances have made both options truly feasible and
have put the means of producing such materials in the hand of (almost)
any instructor. Distribution of multimedia or audio material via CD is
nothing new. However, with an investment of some $200 an instructor can
now add a CD-R/RW drive to his/her station and can produce such material
him/herself on short notice. Bought in bulk, CD-Rs are now about 75 cents
a piece, the cost of a HD diskette not too long ago. While file size is
not a major concern for distribution via CD, it stood in the way of efficient
distribution via course web sites for quite some time.
Via a course web site, which is possibly part of a larger course management
system (e.g., ERes, Blackboard, WebCT)
Via CD-R or CD-RW
However, it now possible to create (voice) audio files of relatively
modest size. Even a 50 minute lecture need not take more than about 6 MB,
or roughly 125 KB/min -- not stereo hifi sound, but decent quality. With
even basic computer models now offering 10 and more GB hard disk space,
storage is certainly not a problem anymore. Still, even a 6 MB audio would
take a long time to download over a telephone modem connection. But thanks
to "streaming" technology, playback starts almost immediately without any
long wait. And 16 Kbps (between one third and a half of the "bandwidth"
a 56K modem connection offers on average) are sufficient for decent voice
audio. This means that a student can listen to the audio and explore the
Web or some (learning) software on his/her station following the instructions
and/or listening to the comments of the teacher at the same time.
Whether an instructor opts for CD or for Web distribution depends on
the teaching style and the target group. With courses that are largely
set with little room for spontaneity and inclusion of recent material,
it makes more sense to prepare one or more CDs before the start of the
course and distribute these in advance. Web distribution, in contrast,
offers the chance to react to need and to opportunity. To need, in the
sense that an instructor can react to students' additional need for explanation
or guidance, reacting immediately to an assessment of the learning and
discovery process. To opportunity, in the sense that -- contingent upon
course topic -- new events may unfold that an instructor want to include
(imagine, in contrast, someone having taught "American Government" in the
fall of 2000 without supplementing his/her original course materials finalized
in the summer of 2000) or an unexpected chance to have a guest speaker
in the class.
While web distribution requires an extra step and may not always work
perfectly given Internet congestion and/or server problems, it is the much
more exciting option from a learning/discovery point of view -- though
this may vary by field and specific topic.
Here is what you need to make this happen -- if push comes to
shoves, with no extra investment at all (check out my
Computer with sound card and the more memory the better, but 64MB should
be fine. Make sure to reboot your computer before you do any sound digitizing
and avoid to have anything else not absolutely needed running at the same
time and competing for "system resources" (memory).
Windows OS. I assume it can be done with a Mac as well, but I don't know
Real Producer (the free basic version will do for starters) -- for web
CD-R/RW drive -- for CD distribution (this may require an extra investment)
Here are the steps
(see also shortcuts below)
Record the lecture (instructions, "tour") with
an ordinary tape recorder. A good tape recorder and a good (external)
microphone help, but this sample
audio tape was made with an over 20 year old handheld cassette recorder
using the built-in microphone. With better equipment (microphone), better
results. Though it may seem extra work, there is some advantage in
creating a conventional tape first -- even if you are sitting next to the
computer recording and could use the microphone connected to your computer
directly. But feel free to experiment.
Digitize your conventional tape. For
this you connect the "line out" jack(s) of your tape recorder, boom box,
walkman, or whatever you use to play back your conventional tape to the
"line in" jack of the sound card of your computer. (The sound card has
three jacks: for microphone, for the speakers/headphones, and the "line
in". You find these jacks on the backside of your computer.) Depending
on the type of device on which you play your tape, you may have to invest
$5 for a "Y cable/connector" at Radio Shack. You need this if you have
a stereo unit with two separate "out" lines. -- Once tape player and computer
are connected, two pieces of software that come as part of Windows can
be used to do the actual digitalization:
Depending on which version on Windows you have, you may find these programs
in slightly different places. On my Win98 SE ("second edition") version,
they are in "Start"/"Programs"/"Accessories"/"Entertainment". But you can
always search for them using the real program names given in parentheses
above. Here is the first of these two programs:
Volume Control (sndvol32.exe)
Sound Recorder (sndrec32.exe)
Volume control is a truly crucial piece for the success of the whole
operation. Note that what you see when it opens (shown above) is not
what you need to look at. This is the playback view, but we need the recording
view. To change, go to "Options"/"Properties" and then select "recording".
Note that "line in" corresponds to "Auxiliary". Make sure that only
the "Select" button in this column is checked -- or you will record sound
from other sources at the same time. The left most column "Recording" is
inactive till you actually start the recording. The bar which looks empty
and gray right now will indicate the recording level by dark green, light
green, yellow, and red squares which form columns of steadily changing
height. The trick is to adjust the incoming volume (by dragging the level
in the "Auxiliary" column on the right) such that you see the column on
the left ("Recording") mostly ending with light green squares (occasional
yellow and even red is not a problem). Both too high and too low a volume
will result in an audio file of very poor quality. Practice a bit with
shorter clips till you get the right feel.
And to practice you need to start the "Sound Recorder" while keeping
"Volume Control" on the screen. By default, the Sound Recorder records
audio clips up to only one minute in length. Enough to practice, we talk
about a work around in a moment.
All you have to do is to click on the button to the right, and click
the "stop" button next to it when you have enough. In the beginning, it
may suffice to record just 20-30 seconds to hear whether the volume control
needs further adjustment. Note that you need to start and stop your tape
recorder independently; great, if you have a remote control. Whether you
hear the tape while you record is up to you and depends solely on whether
you have speakers or headphones connected to your computer and to which
volume level you have set these. Note that this volume level is independent
from the one we have just discussed. And your playback unit probably has
its own speakers/headphone. I recommend to cut off (turn to zero) speakers/headphones
connected directly to the playback unit and just listen to the tape via
computer speakers or headphones.
After stopping a recording, Sound Recorder lets you go back to the start
(leftmost button) and replay (button in the middle), so you can check immediately
whether the sound quality is acceptable. Practice by recording short pieces
till you are reasonably satisfied with the recorded digital audio.
Ready for big time? Here comes the trick to make Sound Recorder do recordings
longer than one minute (I found this in Microsoft's "Knowledge Base" on
Now, it's time to turn the tape recorder on and then click the record button
on Sound Recorder -- all the while keeping an eye on Volume Control to
make sure that the input is of the right volume. When you are done recording
because the 15 min (=900 sec are up) or you have a shorter take to start
with, simply "save as" the recorded file under a name and in a subfolder
Keep the "line in" (your tape playback unit) quiet and record a minute
of silence. Save this file ("File" menu) as "blank1.wav"
Now, select "Insert file" from the "Edit menu" and insert the just saved
Repeat this process, another 13 times, and then save the file as "blank15.wav".
This file "blank15.wav" is huge, almost 20MB, but it will not get bigger
by recording on it. Think of "blank15.wav" of standard template. It is
a good idea to restrict your recordings (and subsequent processing) to
blocks of 15 minutes. You may even deal with smaller blocks of say 10 minutes
if you get error messages about lack of memory.
The first step is completed, but you have a pretty big file at hand. However,
if you plan to distribute the audio file via CD-R, you are done with recording.
The Sound Recorder has several built-in options to shrink file size, however,
so if size should become an issue (e.g., only so many MB left before a
second CD is needed), it is worthwhile to check these out.
You get there via "File"/"Properties"/"Convert Now ....". As you can see,
the sample file was recorded using the default settings: PCM 22,050 Hz,
8 Bit, Mono. But the file size can be reduced considerably, though
sound quality is likely to suffer as well. I will not pursue this avenue
any further since, in general, file size is not an issue for CD distribution
and we will deal with this issue differently for web distribution
Burn your CD (as an alternative to web distribution).
As this process is pretty straightforward, but also depends on the exact
type and model of CD-R or CD-RW drive and its supporting software, I will
not discuss this step in any detail. Let it suffice to say, that "burning"
a CD is about as difficult as writing a floppy -- it just takes longer
and you better don't do anything else on your computer during the "burning"
of the CD. This, of course, is quite a nuisance.
Prepare the audio file for web distribution.
There are currently at least three different vendors offering "streaming"
video/audio. "Streaming" means that playback on the student's station starts
after just a fraction of the file has been downloaded; download and playback
occur at the same time. These vendors are: Real Networks (still the industry
leader), Microsoft, Quicktime. I will focus on Real. All three vendors,
however, offer free "players" -- software that students need in addition
to the regular web browser to play such specially formatted audio files.
The RealPlayer (current version: 8) comes packaged with Netscape. Many
students may have the software already installed, some possibly without
knowing. But I am jumping ahead, we are at the point where we need to create
an audio file in this specific format in the first place.
The needed software tool is the Real
Producer. It comes in both a basic free version and a "Plus" version
which currently sells for $150. I would strongly recommended to try the
free basic version first. This is how I started out (some time in the fall
of 1998). However, the screen shots below are taken from the Real Producer
Plus; the two version look the same on the surface though. Thanks to a
recording "wizard" it is extremely simple to set up a recording (converting)
Here I will only discuss the simplest case, to "record from file". In
other words: to convert an existing audio file (e.g., in the generic .wav
format) to the special Real streaming format. Most of the screens presented
by the wizard are completely self-explanatory. I will comment only on two
choices in this process:
Checking "single-rate" is a safe strategy and does not not require anything
special that your college would have to provide. And for voice only audio
this is sufficient. Note, however, that it is possible to create video/audio
files which adapt to the Internet connection speed of the requesting user
(student). Keep this in mind if you want to move beyond simple voice audio.
Select "28K Modem" (not 56K) as target audience, then you don't have to
adjust the default settings and you get an 16K audio stream automatically.
And this is a good choice if you want your students to be able to listen
to the audio and do something else on the Web at the same time -- all assuming
they have a 56K modem connection. The wizard gives us a final look at what
we have decided to do:
Clicking "Finish" gets you back to the main window. Note the three buttons
on the lower left: "Start", "Stop", "Play". The screen shot is taken after
"Start" has been pressed, and you see a bit of the volume indicator in
the middle between the two green boxes. These boxes would show video input
and output. When "recording (from file)" audio only, you don't hear anything
as the recording (conversion) is faster than what it takes to play the
The blue bar (on the right) is the progress indicator; this screen shot
was taken early on. For the rest just follow the instructions, all straight
forward. If you want to hear how the converted audio file sounds, just
click "Play". This will start the RealPlayer. Assuming, the file still
sounds fine, you are done; you have produced a file in streaming Real format
or an .rm file for short. Using our sample file to demonstrate: the file
size shrank from almost 20MB to 1.6MB with little noticeable loss in audio
quality. Mind you, this original tape recording was not grand due to an
over 20 year old tape recorder.
The "Plus" version of the Real Producer has a number of nice extras,
including the ability to cut and splice Real files. But let's not get into
this for now. There is one more step to go before your students can access
the audio file.
Put the audio file on the server. What
you should find out first is whether or not your college has a "Real Server"
and whether you are allowed to put material on this server. Though this
approach requires some assistance -- at least, the first time you have
produced such a file -- using a "Real Server" has distinct advantages.
To cut through the technical details: your students have a better chance
to hear your audio track in good quality. If you are at Hunter, then, yes,
we do have a "Real Server" and -- at least for now -- I am still the person
you talk to about getting your files up on the "Real Server". After this
is done, you simply put a link to this location on your own course page
(in BB, in ERes, wherever). For example, the sample file here has the following
explicit URL (address):
The ":8080" (technically the port number) is important as both the regular
web server and the Real Server currently live on the same piece of hardware
(named maxweber). Not an ideal setup, and this may change in the future.
If you want to be completely independent, your college does not have
a Real Server, or your college does not let you use it, there is an alternative.
By the way, CUNY/CIS has a license for a Real Server as well. So, there
is no good reason why CUNY Online faculty should not get Real Server space
from CIS. But ....
The alternative is to use the regular web server instead. This
requires a bit extra work, but it is not too bad. The following steps are
Upload the .rm file to the Web server. Example: Upload
"myaudiofile.rm" to a specific folder say ~mkuechle (/home/faculty/mkuechle/www)
on an available server say "urban" at Hunter
Use a text editor to create a file with the .ram extension. This file contains
a single line with the full URL of the location of the .rm file on the
Web server. This URL would be "http://urban.hunter.cuny.edu/~mkuechle/myaudiofile.rm"
(don't include the " ").
Upload the .ram file to the Web server. Upload this
file (consisting of a single line) to the same folder on the server.
Link to the .ram file. http://maxweber.hunter.cuny.edu/~mkuechle/myaudiofile.ram
(the .rm and the .ram file need not have the same file name; it is just
easier to keep track of things)
This sounds rather convoluted, but there is some logic. I have used
this approach in previous multimedia
explorations where you can compare directly how the same file sounds
or looks (video) served from a regular web server and served from a Real
server. If this approach does not work, chances are that the system administrator
for the server has not defined his "mime types" completely. These are instructions
for the browser so it knows what to do with file extensions like ".rm"
and ".ram". It is a truly minor thing (for the system administrator) to
Note on Blackboard/CourseInfo
But what if you don't have access to web server space? It can't happen
at Hunter, because all faculty can get an ERes account and this space could
be used to store such audio files -- if for nothing else. The situation
with Blackboard/CourseInfo is not clear. On the one hand, there is a Blackboard
5.0 "tip sheet" providing detailed instruction about how to tweak BB
to make it work (see box), on the other hand I could not get it to work.
|Excerpt from Blackboard 5.0 tip sheet on streaming
1. Upload the .rm file to Blackboard (using the
"Create a Link to File" Special Action on Blackboard's content-editing
2. Go to the student view of the course.
3. Right-click on the link to the .rm file and
choose "Copy Shortcut" (or, in Netscape, choose "Save Link Location").
4. Open a text editor and paste the copied link
location into the text file. Save this file with a .ram extension (instead
5. Upload the .ram file to Blackboard (using
the "Create a Link to File" Special Action).
6. Set the visibility option on the document
with the .rm attachment to "No."
I tried both CI 4 (at CIS) and BB 5.02 (at both Hunter and BB., Inc),
no success. Maybe even BB, Inc. does not claim that it works in version
4, so forget about version 4. While the .ram file gets passed from the
browser (I tried both Netscape 4.76 and MS IE 5.5) to the RealPlayer (version
8), the RealPlayer was then not able to process the .rm (the actual audio
file) producing an error message that the Player can't handle this format:
Apparently, nonsense, as RealPlayer can play this type of document. But
maybe some piece of information is not passed properly. And since
it does not work at the corporate BB, Inc. site either, it is not a local
installation issue with 5.02 at Hunter.
The only thing I got to work was to leave the .rm file visible (in contrast
to the recommendation) and then click directly on the link to the .rm file.
This initiates a complete download of the .rm file, and upon completion
the RealPlayer plays the audio file. This proves that there is nothing
wrong with the .rm file itself. But this is not exactly "streaming"; of
use for very short audio clips only.
So, at least for now, faculty need to have web server space outside
BB to store their audio files and they have to provide an external link
to this location from their BB course page.
Above, I have described a three step process:
Let us briefly discuss possible shortcuts. Obviously,
when recording an "on site" event (like a lecture in a traditional classroom)
away from a computer, step 1 cannot be avoided. It is possible, however,
to use the input from the conventional tape playback unit (via the computer
sound card) directly with Real Producer. But even Real's own documentation
recommends to record from .wav files rather than "live" input to optimize
sound quality. On the other hand, shorter pieces can turn out quite well
of a 3 minute recording using Real Producer directly with microphone input).
Conventional analog tape recording
Producing a .wav file from the tape recording
Converting the .wav file into the Real streaming
One key question is whether or not the computer
is needed for other tasks during the recording, e.g., when recording a
audio guide how to get around a complex web site like the U.S. Census site
or a licensed data base like InfoTrac or Lexis-Nexis. Recording is "resource
intensive" and doing a conventional tape recording first is the safer approach.
And a computer with plenty of memory is more likely to handle "parallel
processing" (recording and web browsing at the same time) well than one
with more limited resources.
Also, it is fairly easy to tape over sections
we don't like, where we feel we misspoke, etc. during conventional tape
recording. Editing of digital audio files on the other hand requires special
tools that typically are not already available. So, it is an issue of extra
cost and learning more new software tools.
Bottom line: Yes, shortcuts are possible,
but, as a rule, in order to be successful they require better and/or additional
equipment and a bit more experience.
What equipment I use
My work station is really nothing fancy: A Pentium II Gateway (G6-233)
more than three years old (assembled in 9/97), but with 112MB memory, running
under Win98 Second Edition, with 3.7GB hard disk and an Ensoniq sound card
that came with the system.
One crucial add-on is a first rate microphone, an Andrea
DA-400 (used for the "shortcut" samples linked to above), which sells
for around $150, but shop around. A very recent addition is an external
HP 8200 CD-RW drive with USB connection, which sells for about $200.
The conventional tape recording equipment has given me more problems.
I started using a tape cassette recorder (a Sony TCM-121) bought more than
twenty years ago and I was not all that satisfied with audio quality (which
you hear in the sample file). However, not much of a tape recording buff
I failed to realize that there are at least three equipment factors which
determine the quality of the (conventional) recording:
In retrospect, it appears that using an old tape was the main culprit for
the less than perfect quality of the sample file. I bought a new cassette
recorder (first a Sony TCS-580V, later exchanged for a Sony TCM-22DV with
"Clear Voice Function") only to discover that the old recorder does better
(unfortunately, both rewind and fast forward don't work any longer). Only
after adding an external microphone (Sony ECM-T6), I was able to come close
to the quality of the old TCM-121 when using a new tape. The following
file demonstrates 4 conventional recording settings:
the microphone (built-in or external)
the recording heads
the tape itself
Judge for yourself, but I can't hear a significant difference between settings
2, 3 , and 4. Of course, what you hear was digitized with Sound Recorder
first (making some Sound Control adjustment when switching from TVM-22DV
to TCM-121) and then processed with Real Producer. But all three settings
lead to decent audio quality to be distributed from a course web site.
TCM-22DV with internal mike
TCM-22DV with externel ECM-T6
TCN-121 with external ECM-T6
TCN-121 with internal mike
is Sony's low end product, with suggested retail price of only $15. One
disadvantage is that it runs on a CR2025 battery only which is supposed
to give you about 100 recording hours. Other microphones (like the ECM-T115
with a suggested retail price of $45) get their power from the cassette
recorder. So, it may be better to spend a bit more initially. Here is another
file comparing the ECM-T115, the ECM-T6, and the internal microphone
of the TCM-22DV. All three takes are done with the TCM-22DV using a new
type I ("normal bias") tape.
is also towards the lower end of Sony's product range with a suggested
retail price of $60. It comes with rechargeable batteries and an AC adapter
to recharge the batteries or run the cassette recorder directly. Almost
all Sony model can be run using an AC adapter but the adapter is usually
I tried first is considerably more expensive (suggested retail price $150),
but without an external microphone the recording quality was not better
than that of the TCM-22DV. This leads me to believe that going with a lower
end cassette recorder plus a mid-range external microphone may be the best
Whatever you buy, chances are that your cassette recorder is not equipped
to record on type 2 or 4 ("High Bias") tapes. It will record, but the quality
will suffer. So buying cheaper (type I) tapes is the better strategy. If
you really want to know more about tape recording check out the "How
stuff works" site.
Finally, a word of caution: Whatever you are going to buy, determine
the suggested retail price on the manufacturer's site first, then shop
around at retailers (online and stores). Be particularly careful when buying
at discount stores (in NYC): Often they mark the merchandise considerably
above the msrp (manufacturer's suggested retail price), so the discount
they give you is not quite a big as you think. I got the TCS-580V at "Best
Value" on 14th Street for $110 (after some haggling), still a good deal
compared to the msrp but not quite the discount the price tag of $169.50
suggested. Other products had price tags way above the msrp: the ECM-T6
was marked as $49.99 and the TCM-22DV was marked as 99.99.