Miniature loudspeakers

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Miniature loudspeakers

• Acoustic seminar
• Labtec spin-85

Ilkka Huhtakallio, Mikko Maksimainen
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Original speakers
Labtec spin-85 miniature speakers

• Low end miniature speakers price 20
• Total RMS power 3 W
• Frequency 80 Hz 20 kHz
• Drivers 2 high excursion driver
• System THD better than 0.05
• Speaker dimensions(H)x(W)x(D)72.52.5"

These are the values announced by the
manufacturer.
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Magnitude response and surface vibration velocity
of the original speaker
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Impedance response
Resonant frequensies free air , f 311
Hz closed box, f 336 Hz Reflex box, f 347 Hz
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Speaker modification
Cap screws tightened through the
enclosure Damping material inserted
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Magnitude responses of the modified speaker and
the equalized speaker
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Comparison
Magnitude responses

• Original speaker Modified speaker Equalized
  speaker

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Summary and conclusions

• Some flaws in design are impossible to improve
• If the enclosure is poorly designed and made out
  of poor material, it is almost futile to make
  modifications to it.
• The best way to improve the magnitude response of
  a bad speaker is to use an equalizer.
• This way it is possible to reach a magnitude
  response that would be easier to sell, though it
  might still sound awful.