I came across a freeware program on the internet that can turn your computer into a signal generator. In addition to having the usual sine, triangle and square wave generating functions. The program also has a frequency sweep function that will generate signals over a user defined range of frequencies. And what really makes this program useful is that you can create ".wav" files. The ".wav" files created are about 10 seconds in length, so there are not very large. Since, most CD burning software programs can convert ".wav" files into Music CD Tracks. It is possible to export the computer's ".wav" files into something that can be played on a stereo system.

Using the link found below, down load the SigJenny.zip file. The SigJenny program has a standard "Install Shield" setup.exe program. So, installation is rather simple.

http://www.natch.co.uk/downloads/SigJenny/BetaVersion/betaversion.html

For testing a speaker's frequency response, I would recommend using the frequency sweep function. Fixed frequency test tones are very sensitive to room resonances, which can give you false response reading. Sweeping test tones on the other hand, have an averaging effect that is very similar to using pink noise.

To create my own Test CD, I first created 60 ".wav" files. Each file contains a frequency sweep, about 1/3 of an octave wide. And each file is about a 1/6 of octave higher in frequency relative to a prior file. So, this allows me to plot my systems frequency with 6 data points per octave.

The following link is to a handy chart for selecting each ".wav" the frequency ranges.

http://www.drewdaniels.com/freq.pdf.

By using this chart as a guide, I was able to create My Test CD is based on musical notes.

Here is an example: The 440Hz (A4) ".wav" file, which sweeps up and down from 391.995 (G4) to 493.883Hz (B4).

While using sweep tones and a cheap sound pressure meter will never be as accurate as an expensive RTA device using pink noise. I think people will be pleasantly surprised by just how well this little idea works.

Finally here is another application, where I can see this free signal generator program would come in real handy. When tuning base-reflex ports, most tuning methods require the use of a signal generator. Rather then going out and buying one, just create a series of files with fixed frequency tones, spaced 1 Hz apart.