The basis of this project is to make it independent of the headphone jack and the computer and have it in a compact form to be placed in a device.
Welcome to Electronics Point,
@Clemson2019.
So, are the responders here at EP left to produce a 128 Hz sinusoidal oscillator that drives a three or four inch diameter speaker with ten watts of power delivered from a disposable battery? And are you coming to this forum for help because you (1) don't know the simplest way to build this on a breadboard, (2) have no idea what schematic to use, and (3) are pretty new to all of this? That's okay. Some of us here live for the opportunity to help you, no matter how long it takes to squeeze out the information of WTF you are trying to actually
DO. For example,do you expect this thing to repel biting insects? Terrorize mice? Annoy neighbors? Help you tune your guitar?
If all you have done so far is to attach a 3.5mm phone plug to a small prototype speaker and try to drive that from the headphone jack on your personal computer, are you expecting to actually build something, or do you expect us to do all that work for you? What is
your contribution to
your project?
Perhaps the inductance of the speaker voice coil can be part of a power-oscillator resonant circuit? Maybe mounting the speaker in a resonant enclosure tuned to 128 Hz will help produce a sinusoidal audio wave in air? Perhaps you can run the contraption from a set of D-sized alkaline dry cells?
Maybe drive the speaker directly with a class D mosfet power amplifier sampling a 128 Hz sine wave at ten kilohertz or so? As
@Audioguru noted, about thirty volts at 0.6 amps would do the trick. So, twenty 1.5 V D-size alkaline cells would do just fine and enrich the coffers of Eveready and/or Duracell immensely if you run it at full blast for awhile...