RDL ST-HP3 STICK-ON Series High Pass Filter 300 Hz and 500 Hz

Protect PA horns and sharpen voice announcements in security and monitoring systems with the Radio Design Labs ST-HP3 high pass filter. This pro audio processor delivers two dedicated filtered outputs—300 Hz and 500 Hz—so you can protect compression drivers and loudspeakers from destructive low-frequency content while improving intelligibility for paging, surveillance, and public address. The ST-HP3 accepts line-level (+4 dBu nominal) inputs and provides balanced outputs (with unbalanced wiring possible) at unity gain, preserving system levels while applying precise filtering. Its dual outputs can feed separate amplifiers or zones simultaneously, enabling flexible zone control for security, transit, education, and commercial installations. Built with RDL’s SupplyFlex power input, the module runs from 24 Vdc (ground-referenced, floating, or bipolar), streamlining deployment in distributed audio and monitoring racks. Compact and easy to mount, the ST-HP3 is an efficient solution for integrators who need reliable PA horn protection and consistent audio quality in surveillance and security environments. Add the ST-HP3 to your next installation to reduce speaker damage and improve announcement clarity.

• Protects PA horns and improves speech intelligibility by removing damaging low frequencies with dedicated 300 Hz and 500 Hz high-pass outputs
• Dual filtered outputs allow simultaneous feeds to two amplifiers or zones for flexible paging and monitoring setups
• Balanced line-level I/O (+4 dBu) with unbalanced wiring option simplifies integration into existing pro audio and security systems
• Unity-gain operation preserves system levels while filtering; ideal for live sound, paging, and surveillance applications
• Compact stick-on form factor and 24 Vdc SupplyFlex power reduce installation time and fit distributed audio, monitoring, and security deployments