Subwoofers and subwoofers are very popular nowadays, but active subwoofers for cars are rarely introduced. My unit has a Toyota van with a recorder with good sound quality. However, the bass is obviously insufficient. For this reason, an active subwoofer is added, and the effect is more ideal. Now it is introduced as follows. It is better to find a thick and low tube with an inner diameter of about 170MM and a length of 1.5M, if you can find a similar hard plastic tube. Find a section of hard wood and process it on the lathe into the section where the speaker is fixed in the middle as shown in Figure 9-46. Its outer diameter must be the same as the inner diameter of the paper tube to facilitate the fixing of the speaker, and a wire groove is opened on its outer circle , Fix the speaker on the wood, brush the wood with glue, and fix it in the center of the duct. The speaker uses two 8-ohm 6.5-inch bass in anti-phase parallel connection. The power amplifier adopts TDA2005M and is put into BTL format, as shown in Figure 9-47. This is the circuit form that the car power supply can provide a larger output audio power. Although the output power is somewhat insufficient for the subwoofer, in actual use, the effect is quite satisfactory. Rotate the subwoofer under the rear seat of the car during use, and the bass signal can be directly picked up from the speaker, taking care not to connect the phase wrongly. If this subwoofer can be equipped with a subwoofer amplifier of more than 50W and used in a home theater system, its effect is also good.
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June 09, 2020