Why are the middle of speakers so delicate and usually pressed in? Does this affect the sound quality and what would happen if I removed them?
The paper or polymer cones in speaker elements are the parts that set the air waves into motion. They don’t necessarily need to be convex in the center, and I have noticed that many vendors have started making them concave probably because so many people couldn’t resist the urge to push them in (these are the same people who compulsively pop every single blister in a sheet of bubble wrap).
The cones themeselves are supported by a fragile coil, which has to be as mechanically free as possible so it can easily be set into motion by the amplifier current. If the cones are damaged or even just misaligned, you’ll hear some awful buzzing or popping sounds as the cone rubs up against the frame of the speaker when it moves, distorting the sound horribly.
Manual sig line #18
The above mentioned coils are centered around a magnet. I think the center is part of the physical attatchment of the cone to the coil. Current from the amp generates a magnetic field in the coil causing it to move in relation to the magnet. This area near the coil generates higher frequencies and undergoes more stress that the rest of the cone, like the splashes that become larger in size and weaker in strength further away from the rock you threw into the lake.
In general it’s not a good idea to push any part of the speaker cone.
The soft rubber part around the outside of the cone is the suspension and it can be strained if the cone is pushed inwards fron one side of it only .The cone is designed to move in and out evenly, if it moves slightly off then the former which holds the coil will rub on the magnet.
Pushing the centre of the cone in and deforming it may change the quality of the sound as it will move air in a way that is not within its design spec.This may make it less efficient at certain frequencies or may even change the phase of higher frquencies relative to the rest of the range.
That effect is probably going to be subtle and to all intents unnoticeable, but the rubbing of the coil will be very obvious.
that’s the dust cap… if it’s removed, it exposes the coil, and the center pole of the magnet, and dust and other crap will get in there and the speaker will scratch. enough of that goes on, and the wire in the coil could sever, which effectively kills the speaker.