Skip to main content.

Web Based Programming Tutorials

Homepage | Forum - Join the forum to discuss anything related to programming! | Programming Resources

Web Programming Unleashed

Chapter 36 -- RealAudio

Chapter 36


by Mark Bishop


It's hard for me to imagine that anyone who uses the Internet doesn't already know about RealAudio-or any other audio or sound program. (More than 4 million Internet users have downloaded and installed RealAudio Players.) Yet for most Internet users, audio and sound issues are seemingly nonexistent. Everyone wants to have cool Web pages and neat Java scripts, but no one seems to care much about sound.

The time has come to add sound to your Web pages! Sound adds life and excitement and complements the carefully crafted visual elements of your Web site. RealAudio is the product that enables you to become an active participant in the exciting new world of real-time audio on demand.

Traditional uses of audio over the Internet were just like the old days of BBSing. You saw a sound file, downloaded it, and then played it using one of the many existing sound players. Indeed, the way we transfer files today via FTP, Gopher, or e-mail makes excellent use of this conventional method. Many Web page designers wanted to do more than store sound files for users to download-they wanted to create real-time performances with neat things that make a Web page come alive!

The process of delivering sound over the Internet involves many factors. Delivering a sound file in real time through your Web page, or maybe even coordinating your Web pages into some type of presentation, means coping with a multitude of time-lapse variables, such as the speed of your Internet connection (bandwidth), a program to deliver the sound file from the server (audio server) to the end user (client), and the modem/connection (TCP/IP) speed of which the audio file travels to and from.

Time-lapse considerations make the difference between what you hear when you listen to a recording of a single person talking into a microphone (AM quality sound) and what you hear when you listen to a high-quality recording of a symphony orchestra playing Beethoven (FM quality sound). It either sounds decent (sounds are clear and strong) or it sounds lousy (sounds break up and are scratchy). All the non-computer audio devices that we take for granted (our telephones and stereos, for example) have specialized equipment that make them work as separate machines. That is, they sound and operate fine. The difficulty occurs when you put these devices into a single computer (now sound and fax cards) and connect them to the Internet and then try to make them work and sound as they did as separate devices. RealAudio works with your computer's sound devices and makes listening to sound over the Internet enjoyable. RealAudio makes sound happen!

Progressive Networks, Inc., based in Seattle, develops and markets software products (such as RealAudio) that enable users of personal computers and other digital devices to send and receive audio files using their existing sound cards. Figure 36.1 shows the Progressive Networks home page at

Figure 36.1 : Where sound on the Internet began: The Progressive Networks home page.

The RealAudio client/server software enables Internet and online users who have a PC, sound card, and telephone line to browse, select, and play back audio or audio-based multimedia content in real time and on demand over a TCP/IP network. The key term here is real time. Being able to play an audio file while it's being delivered (you can say downloaded) in real time to your computer is a real breakthrough in technology, especially if you compare it with typical audio-download experience. Audio files using conventional online methods can take five times longer to download than to play!

How Do They Do That?

How does RealAudio work its magic? The short answer is that the RealAudio Player works as a plug-in with your Web browser, such as Netscape or Explorer. The client side (the RealAudio Player) plays the downloaded sound file as it's being transferred to your computer, and the server side (the RealAudio Server) delivers the audio file with only a modest CPU impact to your server. The original sound performance was only AM broadcast quality (8-bit, 11KHz sample), but RealAudio 2.0 has better performance: The 14.4 algorithm has very good speech transmission and the 28.8 algorithm delivers monophonic FM quality audio.

The RealAudio Server delivers the audio in streams, using advanced compression algorithms and other specifications. Think of a stream as each user listening to an audio file while it's being transferred-no delays. If you want more users to listen to more audio files on your server at the same time, you obviously need a RealAudio Server version with multiple streams. Each stream requires about 10Kbps of network bandwidth and more money.

Accordingly, for this technology to come together and work, you must first create, or "encode," RealAudio files into a RealAudio format (for example, welcome.RA). This job requires a RealAudio Encoder. The Encoder encodes your sound input in real time with lots of hot features. The RealAudio Player and Encoder are free. By now, you might be wondering why you need three programs to have RealAudio, and what else you need. Let's talk shop on the following: the RealAudio Player, the RealAudio Encoder, and the RealAudio Server.

System Requirements

Before you launch your RealAudio Player, you might want to know its requirements. Although the player works in all Windows environments, the new 2.0 version can play and create versions for either 14.4 or 28.8 modem speeds depending on your hardware. The difference is that the faster modem produces a higher quality sound. Believe me when I tell you that there is a vast difference. Simply put, a 28.8 modem makes your files sound good!

Using Windows

Although version 1.0 of the RealAudio Player has worked nicely for almost a year now, the 2.0 has many significant new features that make this latest version of RealAudio Player the one to use. Among those features are 14.4 (monophonic AM quality sound) and 28.8 (FM mono quality sound) RealAudio (RA) type files. These files are hardware specific, meaning if your Internet connection and modem speed are fast enough (28.8Kbps for example), the server will send the 28.8 RA sound file, so get used to seeing two speeds for RA formats, 14.4 and 28.8. This will be a standard feature as RealAudio servers upgrade because it benefits the server.

If you want to play the 14.4 RealAudio files, you'll need at least a 486/33 DX or faster computer with a 14.4Kbps modem, 4MB of memory, 2MB of free disk space, an 8-bit sound card (a 16-bit card is recommended), TCP/IP (WinSock or equivalent), and an SLIP/PPP Internet or LAN connection. To play the 28.8 high-quality RealAudio sound files, you'll need at least a 486/66 DX or faster computer with a 28.8Kbps modem, 8MB of memory, 2MB of free disk space, your sound card, and a TCP/IP stack and Internet connection. Accordingly, most of you probably already have the necessary components.

If you're a Windows NT user, you must use the 32-bit RealAudio Player because the 16-bit player does not support Windows NT. The RealAudio Player supports over a dozen popular Web browsers, including Netscape Navigator, the Microsoft Internet Explorer, Netcruiser 2.0 or later, and Internet MCI Navigator.

If you use Windows 95 and a later 16-bit winsock.dll driver, such as those found in America Online or CompuServe Internet software, you must use the Windows 3.1 (16-bit) RealAudio Player.

Macintosh Users

Macintosh users who want to play a 14.4 algorithm file need a 25MHz 68030 or faster computer. For 28.8 high-quality sound, Mac users need a 25MHz 68040 with floating-point processor or a PowerPC. Modem speed, memory, hard drive space, and Internet connection are equivalent for Windows and Mac. Web browsers for the Macintosh that support the RealAudio Player include Netscape Navigator, Internet Explorer, NCSA Mosaic, Netcruiser 2.0 or later, and MacWEB. New browsers are continually added, so keep updated by visiting Progressive Networks's Web site at

The RealAudio Player is the crux of the family of audio software products developed by Progressive Networks. It's free to download and widely used, as is the Encoder program. When you visit a Web page that has a RealAudio file, you usually see the icon shown in Figure 36.2, which means that a RealAudio file is present. Icons with a 28.8 designation mean you need a 28.8Kbps modem to handle the file.

Figure 36.2 : The RealAudio icon.

Clicking the icon launches your RealAudio Player and plays the audio file associated with that page. Version 2.0 of the player enables Web authors to play background music automatically or even embed real player controls in Web pages for user interaction.

The RealAudio Player is about 61KB in size, yet it provides a good punch for playing RA sound files. Figure 36.3 shows how the RealAudio Player looks after it is launched.

Figure 36.3 : A RealAudio Player.

The player offers all the regular functions found in a typical tape player: start, pause, fast forward, rewind, stop, and volume control. You can also play an RA file directly from your hard drive or, of course, in a live real-time performance.

Other neat features include a file opening feature for a given URL address (for example, pnm:// under the File section and also a statistics feature under the View section that shows you the number of lost packets sent over your TCP/IP connection. You can use this information to diagnose poor quality sound coming through your sound card.

On the right side of Figure 36.3, you'll see a small speaker. I always wondered why it went in circles. When you see it revolving, the RealAudio Player is looking for the RealAudio Server. Once it's connected, you'll see little sound waves come forth. When you see yellow or red lightning bolts displayed from the speaker, you know that data loss is occurring. Data loss can occur for a number of reasons: a bad connection, too much Internet traffic, or trouble from your own computer and sound card. Just be patient and see if it clears up. I found that running two Web browsers simultaneously made my RealAudio Player choke and the sound quality poor on more than one occasion.

RealAudio Player's Advanced New Features

For those of you with an earlier RealAudio Player, here's a list of the best new features in version 2.0:

Automatic Install

The RealAudio Player works with your browser and is launched as a helper application. When I installed my 2.0 player, the setup program automatically installed and configured both my Netscape and Microsoft browsers to use the RealAudio Player. By default, the RealAudio Player sends a 16-bit, 8KHz sound to your sound card. Unfortunately, some sound cards don't support 8KHz audio.

While the RealAudio Player is being installed, the installer program can talk to your sound card and change the preferences automatically.

Manually Installing the Player

First, locate the Options or Preferences settings menu in your Web browser. Look for the Helper Applications and then look for audio/x-pn-realaudio in the file type list. It is not alphabetized, so scroll down to see audio. If you see it, look at the extensions it supports and the application it launches. You should see file extensions of .RA, ram, and Raplayer.exe to launch the RealAudio RA or RAM files. If not, do the following:

  1. Click NEW for Type.
  2. Enter audio as the new MIME type.
  3. Enter x-pn-realaudio as the MIME subtype.
  4. Click OK.
  5. Enter ra,ram in your EXTENSIONS field.
  6. Make sure the word launch is checked. For the application to launch, browse and find the directory where your RealAudio Player exists.
  7. Select Raplayer.exe as the application to launch. You're finished!

Where To Find Hot Audio Content

I am amazed at how much RealAudio sound is available on the Internet. Doing a search using with the search string REALAUDIO, I found everything from underground bands to full-length songs to famous speeches-all there at the click of my mouse. Most of these sites have directories, like a TV guide, listing live upcoming events.

I visited one site that gave me a host of whole songs on demand, including many live "Internet radio stations." A single word sums up this experience, "Cool!"

Check out the next site for a nice list of music. I found KDGE 94.5 in Texas there. You can actually type messages to the DJs-live on the Internet!

Do you want to check out an entire CD jukebox of sound files? Try Audio Net for one of the largest collections, if not the largest, that has all types of audio in one place. For sports, radio stations, live events, music of all types, and a cool CD jukebox of every type of music you want to hear, point your browser to

RealAudio Encoder

Although you can find plenty of sites for using your RealAudio Player, if you want to make your own RealAudio files for others to hear, you must create them using the Encoder program. This requirement doesn't mean that you can't use another audio program or editor to prerecord your own sound. In fact, programs that come with SoundBlaster and other multimedia packages, even the Microsoft Sound Recorder included with Windows 95, do a good job. The RealAudio Encoder accepts au, wav, and raw pcm formats as its source file, and it even accepts external audio sources that come from a CD player, mixing console, microphone, or digital audio tape.

The RealAudio Encoder is quite easy to set up and use. Select a Source file or Live Stream (like a microphone or mixing board) and then a Destination file. (For live broadcasting, select a RealAudio Server.) I took a small wav file, named it Matthew.wav, and as soon as I finished typing the filename in the Encoder, it went to work and automatically encoded audio clip into a RealAudio RA file titled Matthew.ra. The Encoder also automatically recognizes the audio type of your source file. In my experiment, I had a microphone connected to my SoundBlaster input jack. If the Encoder can't recognize the file type, it asks you to select the Sampling Rate and Resolution (8-bit or 16-bit) formats of the source file. The Encoder also supports drag- and-drop encoding.

Figure 36.4 shows the RealAudio Encoder in action.

Figure 36.4 : The RealAudio Encoder in action.

As mentioned before, the RealAudio Encoder compresses the RA sound file. For example, the original size of a wav file recorded at 22KHz, 16 bit, for one minute was 2.6MB. After using the Encoder, the size dropped to 113KB. How does the Encoder compression scheme work? RealAudio Encoder identifies the important parts of the audio file and tosses nonessential sections. File compression enables you to use your bandwidth to its fullest dimensions, stuffing the audio signal and packet all the way!

Accordingly, you can understand the need to use decent audio recording equipment. If you want to become a serious RealAudio provider, buy professional tools from the sound card to the microphone to the recording software. Fortunately, you won't go bankrupt buying good equipment at affordable prices.

The Making of a Good RealAudio Sound File

Even if you aren't a sound-recording expert, you can make high-quality RA files by following a number of common-sense steps.


Make sure you use a high-quality original source such as an audio CD or that you use a quality microphone. If you want to take that box of old cassettes and make RA files, expect plenty of hiss and distortion once the tapes are encoded into an RA format. Progressive Networks recommends encoding from a 16-bit sound file and digitizing at a 22,050Hz sample rate. Even the Microsoft Sound Recorder offers a recording of CD quality with a 44,100Hz, 16-bit, stereo, 172Kbps sampling. After the file was encoded, it sounded quite good. Obviously, preprocessing your original sound file makes a large and noticeable difference in the RA results. To find good recording software to use to prepare your sound file for encoding, check for the names of shareware programs.

Volume Control

Do you remember the days before stereos came with built-in equalizers? Remember how many slide controls you had to adjust to get quality sound? Once the dials were set, you rarely had to readjust them. The same is true when you make RA files. Although you want to be rather conservative in the sound's volume (not to spike above that red line, whatever that might be), you also want an input level that uses your maximum amplitude. Look for the word Normalize on your sound editor; you can use this function to maximize your input level automatically. Most good sound editors/programs have this feature.

Key Audio Words To Live By

Other audio recording considerations include words such as equalization or EQ that change the tone of the incoming signal. As with stereo equalizers from yesterday, you can adjust the RealAudio Encoder by turning up or turning down certain frequencies. In a way, you are saying, "Yes, I want this sound, but no, I don't want that one." In short, you keep only the good sound. Nevertheless, the Encoder still discards lots of the high-end or treble sound, making your sound file sound flat.

To compensate for this effect, experts suggest increasing the middle frequencies, commonly known as the midrange. This feature also makes the sound file sound better! You should boost this level to about 2.5KHz.

Noise gating, also known as expansion, gets rid of undesired background noise and usually reacts when flat empty spots occur in a recording-for example, when you record from a microphone and do not say anything. Noise gating usually occurs automatically so that the beginning of any sound is not removed entirely. Some sound editors have a range control for this setting, and you should set it at 5 to 10dB.

The term compression is not related to the file size, as you might think of compressing a file, but rather it means the reduction between the loudest and quietest sections of the sound signal. Compression is important because the RealAudio Encoder creates sounds that weren't present before the encoding process. Some call these extraneous foreign sounds "artifacts."

You can avoid artifacts by using a louder incoming signal to mask these sounds. However, you are also limited by the loudest section of the signal. Compression enables you to quiet the loud section and thus turn up the overall volume. The process sounds complicated, but it works.

The best advice here is for the one doing the encoding. When you're recording speeches, a higher compression (4:1 to 10:1 ratio) makes the audio signal loud enough to cover the quieter artifact noises. With RealAudio's 28.8 format under Compression Type on the Encoder program, the dynamic range is increased so that the artifacts are almost nonexistent.

The RealAudio Encoder also comes bundled with two other command-line utility programs that enable you to edit your RealAudio files: RACUT.EXE and RAPASTE.EXE. The first program makes a copy of your RA file (use the status bar on your player to guide you to what portions of the clip you want to save), whereas RAPASTE.EXE enables you to create a new RA file from two or more other RA files.

Can You Hear Me?

When users listen to a RealAudio file for the first time, the sound quality might be worthless. The first thing to explain to the listener is that the quality is similar to AM radio for RealAudio Players 1.0 and similar to FM mono for the 2.0 version. If, however, the sound is choppy or garbled, then consider some of the following hints:

  1. Check your installation. When you originally installed your RealAudio Player, the file Setup is complete should have played by default. Do you recall hearing it? If not, there could be a conflict with the sound card.
  2. Visit other Web sites that have RealAudio files to play. If one site sounds better than others, go to the View section of your player and use the Statistics option to check whether any packets are lost or late. Perhaps the problem is with a particular site.
  3. Check your modem connection. Look for the high-speed HS light on an external modem. Perhaps you assumed that your connection is 14.4 or 28.8, but it's not.
  4. Adjust your modem's port speed. If you have an older serial card with an 8650 UART chip, lower your COM port speed and see if it helps. I recommend buying one of the newer standard high-speed serial cards with a 16650 UART chip. They are actually very inexpensive. If you have the 16650 serial card, increase your COM port speed two to three times higher than your maximum modem speed. (Windows 95 users can use the Control Panel.) Also make sure that for Flow Control, you select Hardware in the Advanced Settings section in the Modem Properties dialog box.
  5. Try closing the RealAudio Player. Then clear your Web browser's "disk" cache. In Netscape Navigator, it is under the "Options and Network" preferences. Then, click the Reload button and try listening again.

After all is said and done, having good equipment and a quiet environment in which to record is essential. Test your sound card by making several recordings that use different input levels and settings to get the maximum amplitude. You might even want to consider hiring a professional announcer to develop your RealAudio content.

RealAudio Server

RealAudio Server is the winner of a number of honored Internet and computer-related awards. It streams RealAudio files in real time over modem connections or networks without any download delays. The process is immediate and fast.

Earlier, I told you to think of a stream as the delivery of a RealAudio file to one person. If you want simultaneous connections, you need the appropriate RealAudio Server and license key.

Progressive Networks' prices for the RealAudio Server vary according to how many streams you want-from a five-stream version (list $495.00) to a 20-stream version ($1,895.00) to 100 streams ($8,495.00). I bet that last one made you gasp! Larger stream packages are available upon request.

A visit to the RealAudio Web site is also worthwhile because Progressive Networks does offer very good support and its Web site offers lots of good help. You can also purchase modestly priced upgrade and support options that include up to 100 hours of free technical help, free upgrades for 12 months, and significant discounts on other items. Even without this upgrade, you still get 90 days of free technical help. I was also impressed with Progressive's Academic pricing, which gives faculty, staff, and students from accredited colleges a 25 percent discount on the RealAudio Server, upgrades, and support.

The Evaluation Program

Progressive Networks also has an evaluation program that gives you a five-stream RealAudio Server to use for up to 30 days. Give it a test drive to see if you want to purchase it. The evaluation package is a real version-not crippleware. You can contact Progressive Networks and apply for the evaluation program at

The Easy Start Program

Progressive Networks put together a decently priced RealAudio package so that you can start to offer cool sounds on your Web site. You, too, can display real-time audio on your Web pages-no more delays for your users and no more waiting to download an audio file. For about $495, you can get a five-stream RealAudio 2.0 Server, the 2.0 Encoder, a 70 percent discount on upgrades and other support, and a 30-day money-back guarantee. For more information, visit the RealAudio Web site at

The Personal Server

You don't have to be a major enterprise with big bucks to enjoy a scaled-down version of the RealAudio Server. You can evaluate your own Personal RealAudio Server that runs on your own PC under Windows 95, Windows NT, or Mac OS. (You need a Pentium computer system and at least a 56K or T1 line to support simultaneous connections.) The Personal Server includes two live streams and one local stream. After the beta period, the retail cost is around $99. Visit the following site for additional information because it's still free:

Installing RealAudio Server

My RealAudio Server came on a CD. The license key is generally included with your invoice, or Progressive Networks sends it to you by e-mail. The installation process was fairly simple, even though an install program would be nice. Using my Windows NT 3.51 File Manager, I simply dragged the required directory contents (E:\SERVER\INTEL_NT\BIN) onto my C:\PNSERVER directory. As I said, all of this is done manually.

All the other components such as the RealAudio Player, Encoder, and utility programs come bundled on the CD. Even all the other available operating platforms such as UNIX are included. To install the RealAudio Server and make it operational, you cut and paste your license key into an ASCII SERVER.CFG file that already exists.

Using Administrative Privileges, you then run the program CRTSVC.EXE from the directory where you installed the server. Here's how my setup looked:

crtsvc c:\pnserver\bin\pnserv20.exe c:\pnserver\server.cfg

This setup places the required entries into your Windows NT Registry. To determine if the setup was successful, you must check the Services menu from the Control Panel.

My original install went fine. In fact, it took only a few minutes to copy the files, change the server.cfg file, and get the player working. If your installation goes bad, you must uninstall and redo. The RealAudio Administrator's Guide is very helpful and worth reading. You can test your install by using a RealAudio Player from a workstation or other computer and typing in the server's IP address.


Select Open Location from the player's File menu and enter the preceding information. If things go well, the player will connect to your RealAudio Server and play the file. If not, you have a problem. At this point I suggest that you call Progressive Networks and get it fixed fast.

The Server software itself works nicely and is supported on many platforms. It uses little of your CPU's processing speed (on a 90MHz Pentium, it uses less than 30 percent of the CPU cycles), and the software itself takes less than 2MB of your hard drive space minus your RealAudio RA files, which are small anyway.

The RealAudio Server does require at least 10Kbps for a 14.4 format and 22Kbps for a 28.8 format for each user connected to your system through the Internet. In short, if you have a 56K line, you are pushing it to the limit with just five simultaneous users accessing RealAudio files in real time. However on a T1, you could support up to 100 simultaneous 14.4 connections-a world of difference. You will probably run out of bandwidth before you run out of computer memory!

The RealAudio Server can work with any Web server that supports configurable MIME types. Some of the platforms tested are Webstar and Webstar PS, Mac HTTP, HTTPD4Mac, Netscape Netsite, EMWAC HTTPS 0.96, NCSA HTTPD, CERN HTTP, O'Reilly Website NT, and Microsoft's IIS. I installed my RealAudio Server onto my Purveyor 1.2, and surprisingly, the folks at Progressive Networks had not yet tested this award-winning Web server with their RealAudio Server. Progressive Networks audio products work with just about any Web server platform. Check the RealAudio Web site to get the latest information on what Web servers its products have been tested on.

Cool Features

The various configuration options of the Server give you a lot of flexibility. For example, RealAudio on a single UNIX machine can run as multiple processes, which enables incoming streams to be balanced on the server's processes. This makes the server more efficient in utilizing its system resources. You can even "cluster" your RealAudio servers and link them together, which provides support for large-stream situations. The previously mentioned Bandwidth negotiation feature enables you to organize your files according to their bandwidth usage. In short, arranging your audio content in a certain order (see Chapter 3 of the Administrator's Guide) enables the RealAudio Server to check first with the end user's player to determine the correct RA file to send.

The client's RealAudio Player contains information about the quality of the connection and other factors and shares this information with the Server. The RealAudio Server then knows whether to send the 14.4 file or the 28.8 file, thus making the best use of the line.

The RealAudio Server comes with a neat MONITOR.EXE program called the System Manager. This program supports remote monitoring of multiple RealAudio Servers and is password controlled. You can use it to graphically monitor performance issues by remotely connecting to your various RealAudio Servers.

Creating a Hot RealAudio Web Site

Without question, sound adds a positive dimension to your Web pages and Web site. I've visited some excellent sites, and I must confess that Progressive Networks made a big leap forward with its 2.0 RealAudio family of products. What do you do after you make your audio files and get your RealAudio Server up and running? Good question.

The Web sites I enjoyed visiting that offered RealAudio files on demand seemed to follow design guidelines that not only entertained me but also made me want to return. The following sections discuss some ways to make a great Web site.

Combine Hot Graphics with Hot Sound

Combine graphics and sound to keep your visitors' eyes and ears busy. Create pictures that talk back to them. You'll receive more hits and returns if you make your graphics interesting and fun. Use the synchronized presentation feature.

Provide Decent Sound

Make sure your RealAudio files sound decent. Who wants to hear junk? Follow the guidelines given earlier in the chapter for making a good quality RA file. Remember to use a good original source, have a good sound card, and record in a good quiet environment.

Change, Change, and Change

Change your audio files often. Change your site and keep your sound files and content fresh and learn to advertise your site. Tell everyone you have on-demand audio-no waits, no hassles. And when you change or update your sound files, tell others. Especially let people know you have RealAudio with RealAudio icons and banners.

Link to the RealAudio Library

Tell people how to get and use the free RealAudio Player. Those neat sites I visited had a single button click that linked to the RealAudio library at the following URL:

Stereo Sound? No Way!

Progressive Networks has beta released its RealAudio 3.0, which brings broadcast-quality audio to the Internet delivering it to your computer and speakers in stereo sound. You need at least a 28.8 bps modem, and with an ISDN or LAN connection you can get near-CD quality sound. RealAudio now builds onto the famous Dolby Net technology along with many other improvements in its software.

When I listened to the differences of the RealAudio Player 2.0 and 3.0 I was totally amazed at the improved quality. My speakers were blasting sound in real stereo! You can hear the differences between the two versions by first getting your 3.0 player and then visiting the comparison page at

The RealAudio Player 3.0 and RealAudio Player Plus 3.0 (a software program that looks and performs like a real radio on your screen) beta versions are currently available for Microsoft Windows 95 and NT and also the Macintosh PowerPC. Visit the RealAudio Web site to learn more about these products.

Summary: RealAudio Only?

Although RealAudio is a superior product for sound on demand, some upcoming companies might eventually put it to the test. One of those companies is the DSP Group, a world leader in digital speech products. TrueSpeech for Windows is a DSP program.

TrueSpeech is similar to RealAudio in that it has a server version and it plays its own encoded sound files on your Web server. However, these files are TrueSpeech's WAV format of files-a common sound file format, indeed. In fact, TrueSpeech 8.5 is built into Microsoft Windows 95 and Windows NT operating systems, and industry leaders such as Intel and Creative Labs have licensed DSP's technology. Even VocalTec, the largest producer of Internet telephone software (such as Internet Phone), is using TrueSpeech's technology.

Although RealAudio is still the superior product, watching the race will be very interesting. Stepping up to the mound after the home runs of RealAudio and TrueSpeech are some other quality programs such as Internet Wave and WHAM. Keep your eye on the ball!