Hear All About It
Leo Robert Klein tells how to bring audio to your library
Leo Robert Klein (netConnect) -- netConnect, 7/15/2001
In the world of multimedia, audio comes up as something of a poor relation--destined always to play second fiddle to the seemingly more glamorous digital video. This is unfortunate because, as the old multimedia adage goes, 'half of what you see is what you hear.' It's doubly unfortunate since even on its own, audio can meet a number of important library needs. Audio is also fun and more immediately accessible. Because it doesn't come with the kind of gigabyte overhead of video, it's less demanding on systems. This means more modest requirements for the computer needed to process it, for the network needed to deliver it, and for the end-computer needed to play it. In other words, the barrier to entry is proportionally low. What's more, many of the tools needed for its manipulation are free--some even coming built-in on machines straight out of the box.
That said, audio is--or at least can be--a science. Whole careers are devoted to its recording, manipulation, and playback. Even those of us who've worked with it on a consistent basis will stand back in awe as a true master of sound engineering brings a scratchy, almost inaudible recording back to health through the wonders of Digital Signal Processing.
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Considering all the possibilities and requirements, audio processing may be daunting. And thoroughly researching a particular field isn't always an option for those with a whole lot of other things to do. To get started, simply look at what you have already in the way of audio together with the potential that digitization and network delivery would bring.
One top candidate in academic and school settings is music appreciation or instruction. Typically, the instructor puts the CDs for the course on reserve, and the students can then pick them up with permission to use them for an hour or two. Come midterms or finals week and competition for these discs can become fierce. How much better simply to point the students to a password-protected page on the library's web site where all the material is listed and to allow them to access this material according to their own needs and schedules?
Equally popular as far as courses go is foreign-language instruction. The digitization of this material will not only reap all the benefits mentioned above, but it may also be a great opportunity to reformat what, in many cases, may still be a collection of antiquated audiocassettes. Instructors can even record new material, remaking the exercises to fit the course's syllabus.
Reformatting and the ability to give greater exposure to material doesn't stop at foreign-language instruction tapes. Depending on the institution, there may be a whole host of audio material collected over the decades either as audiocassette, reel-to-reel, or vinyl that is being underemployed for perfectly good technical reasons--no playback equipment, no expertise in handling, etc.--which could be given a new lease on life when digitized. When made public, such material adds to the growing richness of online resources while at the same time drawing positive attention to the institution making the material available.
Copyright may be a concern in some cases, depending on the uses of the material, how widely access is granted, the age of the material, and its current availability in the marketplace. Keeping in mind that laws governing audio differ in some respects from those covering print materials, every institution should have a good resource to review individual cases.
Another possible area is for lectures where the visual element--say, looking at a talking head for an hour or two--isn't particularly compelling. The lecture may work perfectly well with only audio--or even better, the audio works in conjunction with other nonvideo visual elements such as discussion points, charts and tables, or still photographs and illustrations. Remember filmstrips? The old slide show synced to an audio tract is alive and well, making perfect sense as an instructional tool--and a powerful instructional tool at that--in this bandwidth-deprived world.
Technical nitty-gritty
Once you have decided to try experimenting with audio, the question becomes how. The good news is that the technical requirements are becoming increasingly well known and accessible, thanks in part to the public's almost insatiable thirst for sharing music files. MP3 gets all the headlines, but there are other formats and methods of delivery that may make more sense depending--not surprisingly--on the nature of the material.
The first step is getting the audio into the computer. This may be relatively easy for an audio CD where everything is practically already done. If the audio is on a cassette tape or VHS tape, we first have to transfer it to the computer through the USB or FireWire port; since our analog units typically only come with RCA or serial jacks, we'll have to get a converter to do it. The actual digitization can be performed by any number of software applications, though Bias Peak on the Mac and Sound Forge on the PC are among the perennial favorites.
What digitization does is take something--in this case an audio wave--and measure it at discrete intervals according to a predetermined range of values. The intervals or 'sampling rate' are in thousandths of a second and are commonly expressed in kilohertz (kHz). The predetermined range of values or 'resolution' is measured in bits similar to color depth in images, i.e., 8 bit, 16 bit, etc. The standard audio CD for example runs at a sampling rate of 44.1 kHz and resolution of 16 bit. Such a combination poses no problem for the average home stereo but requires the equivalent of a T1 line to deliver over a network. The trick is to take this stream and somehow compress it so that it can get through a pipe considerably narrower than a T1. This is what MP3 does--now so famously--reducing a stream to a tenth of its original size while maintaining an acceptable level of quality.
Creating MP3 files particularly from audio CDs seems to be one of the most common computing activities of the early 21st century. The software to do this (rippers) are either completely free or dirt cheap. Things to watch out for are whether the ripper produces files of sufficient audio quality (some are hardwired to produce only low-quality MP3s) and whether the compression used to produce the MP3 file is the generally well-regarded Fraunhofer IIS algorithm (there are several others).
The streaming option
MP3 is particularly useful is those situations where quality is essential--say, for an Intro to Music class. Compression is measured in bits per second (bps), with quality seldom dipping below 128. It might be a good idea to work with faculty on general settings since there's a noticeable difference between, say, 128 bps and 256 bps, though in most cases 128 is perfectly fine.
Where you run into problems with MP3 is for longer pieces. Even short MP3 files will weigh in at several megabytes. Particularly where quality isn't an issue--say, in a lecture or narration--it makes better sense to stream the material using either RealAudio or Windows Media. The advantage is that people don't have to wait for the entire file to download before playing. This is why streaming is the typical solution for voice pieces or any recording longer than 15 minutes. Again, the production software is freely available. The drawback is the necessity of a separate streaming server, but even where this isn't possible, encoding in something like RealAudio may make sense for reasons of compression alone: an hour of audio, for example, can be reduced to less than 10 megs, and this may be slim enough even for standard downloading, particularly in a local area network.
Hardware considerations
Curiously enough, audio and libraries are assumed on occasion not to mix. This is strange since facilities have existed for decades for the playback of records and later VHS tapes and audio CDs. In fact, media services have been practically synonymous with the delivery of these formats. Where people get antsy perhaps is when some of the attributes of these traditional forms of media are transferred to the computer. One initial approach was simply to ignore that these things existed online and refer users who wished to access them to someplace outside of the library. More often institutions are concerned about more practical things like the addition of headphones to computers and what this means as far as support is concerned.
Here the model of media centers may serve us well, particularly in those situations where adding a headphone to every computer isn't practical. A dedicated area can be set up where audio capabilities are afforded--even individual 'AV' computers. Certain CD-ROM databases are run on dedicated terminals. There's no reason why, in a pinch, digital AV can't be offered in the same way.
This equipment should not take any more attention from the systems folks than the rest of the libraries' terminals. Routine inspections should be made as to whether the units are in working order and that the software configuration is correct and up-to-date. There's nothing more demoralizing than walking into a room where the equipment is falling apart.
Headphones are the only potentially new equipment. Generally, a good sturdy set of headphones can last at least two to three years. Besides being sturdy, perhaps the most important consideration for choosing headphones is their frequency range. This indeed is the same consideration for choosing a mike. The 20/20 of human hearing is anything between 20 hertz (Hz) and 20 kHz. Both mikes and headphones that come closest to this range pick up the nearest thing to the human ear and are, for this reason, typically the most expensive. A narrower (and hence cheaper) range will almost always do, though it's important not to stray too far. Moderately priced mikes and headphones still afford excellent sound provided you don't overlook things like frequency range.
Workflow
One advantage of audio is that once the process is worked out, routine production becomes simply a matter of paying attention to details: Is the digitization complete? Are there any pops and clicks? Is the amplification loud enough without any distortion? Are the compression settings correct?
Often students or volunteers can come in to run the humdrum conversion. With the labor taekn care of, a passable audio production unit can be put together with a relatively modest investment.
Leo Robert Klein (leo_klein@baruch.cuny.edu), MLS, is Web Coordinator and Digital Resources Developer, William and Anita Newman Library, Baruch College, CUNY. He received a master's degree from the Interactive Telecommunications Program at New York University
