Manfred Kuechler (Hunter College)

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 be obtained.

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.

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 setup):

Here are the steps

(see also shortcuts below)
  1. 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.
  2. 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:
    3. 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 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 the Web):

    1. Keep the "line in" (your tape playback unit) quiet and record a minute of silence. Save this file ("File" menu) as "blank1.wav"
    2. Now, select "Insert file" from the "Edit menu" and insert the just saved file "blank1.wav".
      3. 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.
    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 you designate.
       
    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 (see below).
       
  3. 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.

    4.  
  4. 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.

    5. 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) session:

    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 original tape.
    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.
     

  5. 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):
    6. http://maxweber.hunter.cuny.edu:8080/ramgen/kue/VC-intro2.htm
    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 involved:
     

    1. 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
    2. 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 " ").
    3. Upload the .ram file to the Web server. Upload this file (consisting of a single line) to the same folder on the server.
    4. 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 fix this.

    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 media

    1. Upload the .rm file to Blackboard (using the "Create a Link to File" Special Action on Blackboard's content-editing form).
    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 of .txt).
    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.
     

Shortcuts

Above, I have described a three step process:
  1. Conventional analog tape recording
  2. Producing a .wav file from the tape recording
  3. Converting the .wav file into the Real streaming (.rm) format
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 (example of a 3 minute recording using Real Producer directly with microphone input).

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 test file demonstrates 4 conventional recording settings:
  1. TCM-22DV with internal mike
  2. TCM-22DV with externel ECM-T6
  3. TCN-121 with external ECM-T6
  4. TCN-121 with internal mike
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.

The ECM-T6 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 test 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.

The TCM-22DV 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 not included.

The TCS-580V 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 strategy.

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.