Using a computer as a signal generator

[wil3]

Hello. I am trying to build a version of a Chladni plate, which is a device that uses a modified speaker assembly to mechanically resonate a dish containing salt or some other powder. When the input signal reaches the resonant frequency of the plate, crazy patterns start to appear in the salt.

I have everything I need to create the physical device, but I am baffled as to how I can create a sinusoidal signal that I can easily modulate. I do not want to buy a signal generator, and so I am curious if there is a free program where I can generate a sinusoidal signal on my computer (preferably that I can easily adjust the frequency of with sliders)

Also, I plan on using two 8 Ohm, 2 Watt speakers. Do I need to purchase some sort of amplifier? If so, what specifications should I look for?

Thanks and happy holidays.

 

[Päällikkö]

Just to make sure I've understood your setup: You want to plug in your speakers to your computer's audio output, correct?

Well, you could use for example Octave (a free Matlab clone) to generate WAV-files with the wanted properties and play them out (most probably you can play the sounds within Octave as well, so you can do real-time stuff if you want to).

As for the amplifier, I don't really know. With speakers of that size, I think that without one, it's not going to be very loud. Try it out and report the results.