LAB 21 HS是一款适用于低频高端扩声的扬声器系统，使用一个21寸钕磁长冲程低音（6.5寸音圈）。 负载一个混合波导间接辐射系统，能够完全恢复从其21寸低音单元后部发出的低频声压，这意味着灵敏度提高了6dB（声压级）。 换句话说，在相同的输入电压下，相比在密闭箱体里的同一喇叭，在整个低频段，该系统能提供额外的6dB，平均而言，如果与号角式、反射式或带通式系统一起使用，相比同一喇叭，在低频可提供额外的3dB 。

声音是由两股气团通过单一个振膜流入产生的，这对瞬时频率的攻击速度有很大的帮助，从而产生有深度的、非常干净的低音。 作为一个完整的系统，LAB 21 HS确保了非常高的电声转换效率，这要归功于其出色的机械和声学领域的集成。 这些方面的协调以及专用功率放大器（Outline (欧浪) T Eleven）使最大的能量传输和输出功率控制完全符合输入信号的动态。 LAB 21 HS的频率范围在-10 dB为23 Hz 至165 Hz（建议最大分频点为100 Hz）。 可使用手推车确保快捷运输且有效保护箱体前部免受碰撞。 箱体表面采用特殊的优质耐磨和耐候喷漆。 16个战略定位集成把手方便运输。

LAB 21 HS is a loudspeaker system suited to high-quality sound reinforcement of infra-low frequencies. It comprises a NdFeB 21” long-excursion woofer magnet (6.5″ voice coil). Loading is a hybrid waveguide indirect radiation system able to completely recover low frequency sound pressure emitted from the rear of its 21” woofer, which means an increase in sensitivity of 6 dB SPL.

In other words, with the same input voltage, this system gives an additional 6 dB over the entire low frequency band compared to the same speaker used in a closed cabinet and, on average, an additional 3 dB compared to what the same speaker would give at low frequencies if used with a horn-loaded, reflex or band-pass system. The fact that the sound is generated by two masses of air moved by a single diaphragm, greatly benefiting attack velocity in the transitory frequencies, results in deep, very clean low frequencies.

Intended as a complete system, the LAB 21 HS ensures very high electro-acoustic transduction efficiency, thanks to its excellent integration of the mechanical and acoustic domains. The coordination of these aspects, along with the dedicated amplifier (Outline T Eleven), enables the maximum energy transfer and output power control fully respecting input signals’ dynamics.

LAB 21 HS has a frequency range at -10 dB of 23 Hz to 165 Hz (maximum crossover frequency suggested: 100 Hz). Among the optionals available, a trolley ensures fast handling and efficient protection of the front of the enclosure against impacts. The black finish is in special high quality wear and weather-resistant paint. Sixteen strategically positioned integral handles facilitate handling.