The high-purity oxygen free copper dual parallel upgrade line can restore the on-site sound in three dimensions and bring immersive and shocking sound effects. With ingenuity to the original intention, careful material selection and careful production. High purity oxygen free copper, high-frequency ductility, more straightforward and transparent sound, bright high-frequency, stronger low-frequency texture, light voice and rich details. Three frequency listening sense is smoother, and the purity and fidelity of sound are more guaranteed.