JBL Professional VT4880A Fullsize Arrayable 2-18" Subwoofer with Ultra Long Excursion woofers JBL Professional VT4880A Product Description The JBL VT4880A Dual 18" Ultra Long Excursion Subwoofer Line Array Element was designed to produce a superior quality sound of sub-low frequencies for live music and A/V support applications. Use the VT4880A at a concert or multi-media presentation where extended low-frequency performance is needed!