A thin 27‐mm‐o.d. disk transducer (from Radio Shack 273‐060 signaler) is RTV sealed to the end of a measurement tube whose 15 mm i.d. not only approximates the transducer disk's nodal circle but also the i.d. of a clarinet, sax, or trumpet mouthpiece. A 10‐mm‐o.d. electret microphone element (Radio Shack 270‐092) mounted through the tube wall near the piezo driver picks up the resulting pressure signal. When the high mechanical impedance driver is excited by a sinusoidal sweep via a 6‐dB/oct integrator, the resulting pressure signal gives an excellent view of the input impedance of the air column over the musically useful range to 3.5 kHz since the driver resonance is at ω0/2π≃5 kHz and bandwidth g≃ω0/6. A ramplike drive voltage (running between op‐amp supply limits) of the form for θ⩽t⩽2π/ω0, and constant thereafter, gives a clean pressure pulse ≃ const.(1 − cos ω0t) whose FWHM≃0.1 ms is convenient for impulse response studies. Drive signal spectrum, piezoelectric coupling, and driver‐to‐tube coupling each minimize transducer second‐mode ringing effects. Driver‐to‐mike proximity effects are small, visible, calculable, and easily allowed for in both impulse and sinusoidal drive usage. The driver is not quite rigid, perturbing the air column slightly, but corrections are straightforward. Applications for research and in teaching labs will be described. [Assisted by NSF.]
Skip Nav Destination
Article navigation
November 1982
August 12 2005
Impedance and impulse response measurements using low‐cost components
A. H. Benade
A. H. Benade
Case Western Reserve University, Cleveland, OH 44106
Search for other works by this author on:
J. Acoust. Soc. Am. 72, S63 (1982)
Citation
M. I. Ibisi, A. H. Benade; Impedance and impulse response measurements using low‐cost components. J. Acoust. Soc. Am. 1 November 1982; 72 (S1): S63. https://doi.org/10.1121/1.2019992
Download citation file:
Citing articles via
All we know about anechoic chambers
Michael Vorländer
A survey of sound source localization with deep learning methods
Pierre-Amaury Grumiaux, Srđan Kitić, et al.
Does sound symbolism need sound?: The role of articulatory movement in detecting iconicity between sound and meaning
Mutsumi Imai, Sotaro Kita, et al.
Related Content
Recent progress in measurement methods for studying acoustic radiation
J Acoust Soc Am (August 2005)
Full field visualization towards developing improved ultrasonic test procedures
J Acoust Soc Am (August 2005)
Detection of broadband acoustic pulses in liquids using wideband differential interferometry
J Acoust Soc Am (August 2005)
Measurement of room‐averaged spectra from complex sources
J Acoust Soc Am (August 2005)
Volume perturbers as possible sound field randomizers in room‐average spectrum measurement procedures
J Acoust Soc Am (August 2005)