The thinness of the shell proved to be inadequate, so a heavier substitute developed. 둘째, 목재를 구부려서 두꺼운 MDF의 무게 없이도 강도를 높일 수 있었습니다. Onkyo employs what they refer to as OMF Onkyo Micro Fibre, or more specifically AOMF for the woofer driver.