t was waayyy back in May 1999, and I was attending a meeting where people were going to demonstrate MPEG-1, Layer-3 (MP3) audio. The next thing I knew, I had "volunteered" to write an article about the meeting for the Philadelphia ITVA newsletter. After doing the research, I decided to set this page up to share some of what I had learned. Some ITVA members may have seen that article by the time they read this web page. For you others, the expanded and enhanced version of that article is available right here on this website. Online mp3.
The meeting inspired me to explore MP3 for my own use, and among other things, this page shows some of the results. By the time you read this, years have passed and MP3 is old news, but this gives you some insight about how it got to where it is -- and reveals things about it that you might not know.
As test material, I used samples of my own narration work, since I am naturally very familiar with the original sound quality. Not only will you see the size savings using MP3 compression; you can also do your own listening test, comparing a couple of the MP3 files to the same sound samples stored in older file formats.
First, the new files, in MP3 format. The chart shows the incredible size savings achieved. (NOTE: when you click on any Download link below, in some browsers the download may begin immediately. Your computer may even be set up to play the files virtually in real time. In others, you may get a warning message about a "possible security hazard." If so, don't worry. There is nothing weird about these files. Enjoy!)
First, I sampled each sound clip into standard Windows WAV files at 44,000 Hz, 16-bits, which is essentially "CD-quality," to get the most out of the source material. Since the sources varied greatly, that high a sampling frequency was overkill in some cases, but I wanted the process to be consistent. The files were all monaural to start with.
In the second step, when encoding them to MPEG, I chose one of the lowest settings for "bit rate" because that reduces the file size, and does not seem to make a radical difference in the sound quality when played back over a typical computer system. (I look forward to getting input and opinions from visitors here as to whether that compromise on bit rate is indeed acceptable.) Further on, you'll find a few of the identical samples in other file formats, so you can compare the resulting quality if you're interested.
With that free mp3 download
Since the time this page first went online, the MP3 file format has become a defacto standard. Nowadays, rather than ask for a voice tape or disk by mail, many clients ask for demos in MP3 form via email attachment. Nine years ago, the whole thing was still just an experiment! MP3 is a "lossy" algorithm, in that it throws away data in order to shrink the file. However, it is designed "psychoacoustically" so that you and I are not supposed to notice the missing data. That's why the files still sound surprisingly good after shrinking so much. That's why it became so popular, and that's why you probably have a bunch of them on your computer, or your portable listening device (whatever brand it is!) or even your cell phone. Change happens fast!
Many programs will digitize an analog input signal, using a standard computer sound card. There's one included in Windows, and many sound cards include a small utility for that purpose. I used an old copy of "SoundForge" that I had available. Besides allowing for easy editing, it has other features for preparing the WAV files. There are scads of other programs that can do the same tasks nowadays.
When I first compiled this page, there were comparatively few tools available to encode MP3 files with WAV files as the source. I'm sure there are many more now, but for the record (no pun intended), I used a trial version of an encoder called "Sound Limit" from Eastern Digital Software to make the files here. That company appears to have given up on distributing the program, but you can still find it -- and many other similar products -- at shareware download sites. You can probably accomplish this task with many conventionally-sold products, too.
How to Play MP3 Sound Files:
MP3 playback can be done with several programs, and that list is also expanding rapidly. I used one of the better-known programs in this category, called "WinAmp," for testing my results. It is a multipurpose program for Windows users, and useful for playing back WAV files, inserting author data into files, and more.
WinAmp was "shareware" ($10) when I first put this page online. Now, just a few months later, it is free -- and is even included with the latest versions of the Netscape Navigator web browser package. You can find MP3 files, and playback systems, everywhere you look nowadays.
A company called XAudio provides the decoding software "engine" for numerous MP3 players, for multiple types of computer environments, including Unix, Windows CE, AIX, and of course, Windows and Macintosh. You can go to the XAudio website [Revised URL] for more information and/or free downloads.
For comparison, you will find links below to files that are already accessible elsewhere on this site. When I created them three years ago, I was concerned about file size because of the Internet bandwidth/speed issue, so I edited them as tightly as possible, then digitized them with a very low sampling rate of 11KHz, 8 bits per sample, monaural.
Despite that low rate, they don't sound that bad, since they are mostly concerned with voice (as opposed to music). But as you can see from the numbers above, the MP3 versions of these same samples, originally sampled at a higher rate, still result in smaller file sizes. If you're interested, you can compare the quality between these two formats by listening to the files below and their counterparts above.
NOTE: Please don't download all 3 versions of each! If you have a compatible player, they will all sound identical. The different file formats are simply provided as a convenience for users with varying types of computer systems.
Journey Toward the Light (excerpt; short version) (155K)
Voices of a Small Town 100 Years Ago (216K)