PASCO WA-9900 User manual

Instruction Manual
Manual No. 012-08267A
Open Speaker
Model No. WA-9900

Model No. WA-9900
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Table of Contents
Equipment List........................................................... 3
Introduction ............................................................. 4
Suggested Experiments ................................................. 4
a) Studying Wave Properties..........................................................................................................4
b) Resonance of an Air Column.....................................................................................................4
Specifications ........................................................... 5
Appendix A: Technical Support ........................................ 5

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Model No. WA-9900 Open Speaker
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Open Speaker
Model No. WA-9900
*Use Replacement Model Numbers to expedite replacement orders.
Included Equipment Replacement
Model Number*
1. Open Speaker WA-9900
Additional Equipment Recommended (for Experiments)
Economy Resonance Tube WA-9495
Function Generator PI-9587C
Banana Plugs (red and black) SE-9750 (red set)
SE-9751 (black s et)
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Open Speaker Model No. WA-9900
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Introduction
The Open Speaker is designed for the study of sound wave properties
including frequency, amplitude, pitch, wavelength, and resonance.
The rugged aluminum bracket holds the speaker perpendicular to the
table and provides two standard banana plugs for power input. The
speaker is a 5 ¼” woofer with a polypropylene cone and high
efficiency 10 oz. magnet.
The Open Speaker is designed without a speaker cabinet to reduce the
resonance of the air surrounding the rear of the speaker. This helps
students to more easily hear the resonance created in a closed or open
tube of air.
Suggested Experiments:
Equipment Required: Open Speaker (WA-9900), Economy
Resonance Tube (WA-9495), Function Generator (PI-9587C), Banana
Plugs [SE-9750 (red set of 5), SE-9751 (black set of 5)]
a) Studying Sound Wave Properties
1. Connect the Open Speaker to a function generator using standard
banana plugs.
2. Ask students to listen to the sound as you change the amplitude and
to write down the property of the sound that is changing. Help
students to mentally connect the amplitude of a sound wave to the
volume.
3. Repeat step 2, but instead of changing the amplitude, change the
frequency of the sound. Ask students for the “music” term for
frequency (pitch).
b) Resonance of an Air Column
1. Connect the Open Speaker to a function generator using standard
banana plugs.
2. Place the Economy Resonance Tube (WA-9495) directly in front of
the Open Speaker (See Figure 1 on the next page).

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Model No. WA-9900 Open Speaker
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3. Ask students to adjust the Resonance Tube such that a 50 cm closed
tube is created.
4. Have students start at a frequency of 50 Hz and increase until they
find four different resonant frequencies. Ask students to look for a
pattern in the data.
5. Increase the length of the closed tube to 100 cm and repeat step 4.
Have students compare/contrast their data from the two different
length tubes.
6. Remove the inner tube from the Economy Resonance Tube and
repeat the experiment. Have students compare/contrast their data
for the open and closed tubes.
Specifications:
Open Speaker
Frequency range: 80-80,000 Hz
Diameter: 5 1/4” woofer
Maximum power: 60 Watts
Sensitivity: 85 dB
Impedance: 8 Ohms
Figure 1: Placement of Resonance Tube relative
to the Open Speaker

Open Speaker Model No. WA-9900
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Appendix A: Technical Support
For assistance with the WA-9900 Open Speaker or any other PASCO
products, contact PASCO as follows:
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: [phone]
FAX: [phone]
Web: www.pasco.com
Email: [email protected]