1. Double voice coil. Two unconnected wires are used to wind around the same circle of skeleton soil, and their ends are independent of each other. In general, two wires have the same number of turns and length, so they have the same characteristics.
The specific winding method is to first wind one coil on the voice coil bobbin, and then wind the second voice coil on it. Lead out with two lead wires respectively (four lead wires in total), two sets of lead wires are usually present.
2. The advantages of dual voice coils. The most basic benefit of dual voice coils is the flexibility in the use of voice coil impedance values. This dual voice coil speakers can be connected in series, parallel and directly. For example, a 4Ω dual voice coil speaker is 8Ω when connected in series, and 2Ω when connected in parallel.
You can also connect dual voice coils to the left and right channels of the amplifier. This method is sometimes useful. If some stereo amplifiers cannot or are inconvenient to connect to mono, this method has its own convenience. You can also connect a four-channel amplifier to dual-channel for ultra-low frequency use. In the low frequency box in the home theater, if you use dual voice coil speakers, you can get good results.
3. Another dual voice coil. This kind of voice coil dual-use a folded ring connection part, as shown in the figure above. For low-frequency input signals, the voice coil vibrates. For high-frequency input signals, the voice coil of the heavier part with more turns does not move, while the voice coil of the lighter part with fewer turns vibrates. This reduces the high-frequency impedance, so that the high-frequency and low-frequency parts get a uniform response.