Using Loudspeaker Properly

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The origins of cross-over

In the beginnings (old days) the speakers kept blowing up. The 1st to die is the tweeter because it is wired in parallel with the mid and the woofer.

As the volume increased all the power is equally distributed to each respective speaker. The tweeter being such a small device, with it's puny voice coil cannot withstand the high power.

The 2nd to die eventually is the mid, since it is also relatively small compared to the woofer.

Further case study reveals that the tweeter does not need all the energy. Therefore a high-pass filter (passive) is made and put in series to the tweeter's wiring to protect it from low frequencies, hence stopped the primary excessive power abuse. The cross-over point is often higher than F3 for further protection.

Next the mid also does not need the same amount of energy as the huge woofer, therefore a high-pass filter (passive) is made and put in series to the mid's wiring to protect it from low frequencies, stopped the primary excessive power abuse.

Thank goodness passive filters technology is available from the telecommunication industry and easily and quickly adopted into audio use.

However passive components are not without compromise and penalties. Often the loudspeakers' impedance is bias / swayed and cause un-predictable side-effects. For details please reference from audio cross-over textbooks.

The application of power efficiency also includes low-pass for the mid on frequencies being reproduced by the tweeter. This achieve many objectives.

  1. No two speakers are producing the same sound
  2. The mid is freed of excessive energies and is able to withstand high power
  3. due to 1. the sound quality / clarity improves tremendously.

This makes the mid to use a band-pass filter, instead of high-pass only.

The woofer also receive a low-pass filter, again for the same reasons as the mid, but not for protection, but more for efficiency optimisation and 

Summary: -

  1. Tweeter - needs high-pass filter
  2. Mid - needs band-pass filter
  3. Woofer - needs low-pass filter (


  1. Using Loudspeaker Properly
  2. The origins
  3. Introducing Cross-overs
  4. How they look physically
  5. How the response looks like
  6. Passive vs. Active



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