Sonometer System - WA-9757



With the classic sonometer, students can investigate waves on a wire by adjusting the wire tension and length and listening to the difference in tone when the wire is plucked or bowed. It is a useful demonstration, but it is only qualitative.

With the PASCO Sonometer and the Driver/Detector Coils, students can vary the density, tension and length of the wire, adjust the driving frequency and examine the resulting waveform in full detail on an oscilloscope or computer interface. This is all done quantitatively.

Features include a slotted tensioning lever, magnetic mounts, built-in scale and a sound box.

In the Laboratory

The included Sonometer Manual contains a discussion of the theory of waves on a stretched string, and student-ready experiments for investigating the resonant modes of a stretched string and for measuring the velocity of wave propagation on a string.


Using a 550 or 850 Universal Interface to monitor the detector signal makes it easier to measure and document the relationship between the wave amplitude and frequency. Use the Fast Fourier Transform (FFT) mode for a more sophisticated analysis of wave behavior on a string. The Sonometer's immediate audio feedback from the vibrating string with PASCO Capstone's sophisticated analysis techniques adds reality to advanced concepts.


  • Driver Coil -- Use a function generator to drive the wire at set frequencies.
  • Built-in Millimeter Scale -- Determine lengths quickly and easily.
  • Detector Coil -- Monitor frequency and amplitude at any point on the wire with an oscilloscope or computer.
  • Sound Box -- Students can hear the sound of the plucked or driven wires.
  • Slotted Tensioning Lever -- Adjust the tension quickly and accurately using a single hanging mass (1-2 kg). Vary the tension instantly by factors of 2, 3, 4 or 5.
  • Magnetic Mounts -- The two movable bridges and the Driver/Detector Coils mount magnetically to the base, so setup is easy and components stay put.
  • Uses Standard Guitar Strings -- They come in a variety of linear densities and can be changed in seconds.


  • Base with magnetic mounting strip, sounding board, tensioning lever and wire positioning screw
  • 10 Solid Steel Wires— 2 each of 0.245, 0.356, 0.432, 0.508 and 0.559 mm diameter
  • Detector Coil
  • Driver Coil
  • BNC-to-Banana Plug Adapter (used to connect to interface)
  • Instruction Manual and Experiment Guide
  • How It Works

    The Driver/Detector Coils are key elements in quantifying Sonometer experiments. The coils magnetically mount on the Sonometer base. Power the driver coil with a function generator or computer interface power amplifier. Monitor the resulting waveform (from the detector coil) using any oscilloscope that has a 5 mV/div range or a computer interface.

    Buying Guide

    Slotted Mass Hanger
    Slotted Mass Set (1 g resolution)
    Slotted Mass Hanger   SE-8703A
    Slotted Mass Set (1 g resolution)   SE-8704A

    For use with a Universal Interface, the following products are also required:

    Required for Standalone Use

    Interface Required

    A 550 Universal Interface or 850 Universal Interface is required for use with this product.  Compare the 550 and 850.

    Have specific questions or need more information? Contact Teacher and Technical Support.  We're here to help!

    Software Required

    This product requires or recommends PASCO Capstone for data collection and analysis.