Denting out a dustcap

Unfortunately, it regularly happens that dust caps on speakers are 'pressed in'. The dust cap is the (often dome-shaped) cover at the heart of the speaker. The dust cap serves to keep dust and other dirt out of the interior of the speaker. Dust caps are relatively vulnerable and have an enormous attraction for children's fingers. Here we explain how, with the help of a vacuum cleaner, the dust cap can be brought back into shape.

Unfortunately, this 'trick' does not always work. When it comes to a soft plastic or fabric dust cap, the dust cap can often be restored 100%. With paper dust caps it is more difficult, especially with relatively thick paper dust caps, the material not only dents, it can also tear. In that case, complete recovery is not always possible and replacement of the dust cap may be considered.

Woofer with a dented dust cap

The suction of a vacuum cleaner is able to get a dented dust cap back into shape. The trick is to develop enough force to 'undent' the dust cap but not enough to damage the speaker. To prevent damage, the following measures can be taken:
  1. Support the cone with one hand. This prevents the suction from acting on the cone. The force only needs to be applied to the dust cap.
  2. Limit the suction. A powerful vacuum cleaner, when used at full power, can exert so much force that the entire dust cap is pulled off the cone. It is therefore best to use a vacuum cleaner with adjustable suction power and to start at the lowest power. If more force is required, the suction power can be gradually increased until the dust cap 'springs' into shape again.
  3. If there is no suction power control, gradually move the mouth of the vacuum cleaner towards the dust cap to regulate the power. This is best done by two people. One person supports the cone, the other person holds the vacuum cleaner mouth with two hands and slowly moves it towards the dust cap. The closer you are, the more suction power. The vacuum cleaner nozzle often does not have to touch the dust cap to get it back into shape.
The suction of a vacuum cleaner is able to get a dented dust cap back into shape

Mission accomplished. This woofer is equipped with a linen dust cap, which can often be reshaped with good results.
The dust cap is back in shape after use of a vaccuum cleaner

Scary? Afraid of making a mistake and damaging the dust cap? Before trying the above method, you can also try a method with double-sided tape. Carefully apply the double-sided tape to the dented dust cap. Try to create as large an 'adhesive area' as possible so that the tape adheres well to the dust cover. Then place a (clean & dry) finger on the other sticky side of the tape and gently try to 'pull out' the dust cover. Whether this method works depends mainly on the adhesive strength of the tape and the size of the surface that can be stuck to the dust cover.

© Good Hifi VOF