In 2017, ISP Technologies, LLC designed a custom outdoor wireless system for Downtown Rochester, Michigan. This is an update to answer questions ISP has had from other municipalities and outdoor specialty venues.
The Rochester system is a completely custom design including a custom designed wooden box made with marine grade Baltic birch then sealed with a poly-urea spray on finish inside and out including custom color matching with UV protection coating to avoid any fading from the sunlight. There is no question that a birch cabinet sounds considerably different than a plastic enclosure, far more high performance especially in the mid and low frequencies.
The internal speakers are a very high quality coaxial speaker. This is a very high performance speaker and not what you would typically see in an outdoor speaker from any competitive product and includes a high performance neodymium woofer and compression driver . This speaker is rated at 480 watts program power. The Rochester cabinets have dual 6.5 inch coaxial speakers with one pointed out each side of the cabinet covering both directions down the sidewalk. The cabinets are designed and tuned for the selected drivers used to optimize the bass performance of the cabinet. The entire system is then tuned and precision equalized to deliver excellent fidelity for background music while allowing proper headroom for announcements.
The next critical element of the design is the available power to drive the speakers. In order to achieve performance required for a public address announcement system you need to be able to deliver a minimum sound pressure level of at least 95db at 1 meter. ISP Technologies preference is to have over 100db SPL available to avoid any distortion. The ISP systems have local power amplifiers using our patented DAA Dynamic Adaptive Amplifier technology. With 3 new patents covering this power amplifier technology ISP can deliver any required power at each speaker including a true Bi-Amplified system with a precision tuned crossover. This means considerably better headroom, better clarity and better fidelity with an emphasis on ruler flat response and excellent headroom in the critical midrange. This is extremely critical for intelligible PA announcements with very low distortion. The DAA power amplifier technology allows us to deliver local power with less current draw and at extremely low voltage. Where most distributed sound systems can only deliver between 30 and 60 watts per speaker the ISP systems can deliver upwards of 600 to 800 watts per speaker dynamically allowing us to match the required power of the actual drivers used. In the Rochester system the available power with 32 speakers is over 20,000 watts. This power is only required if the system is used for announcements but covering this kind of area the system does utilize the available power when used for announcements. For any competitive system to deliver this kind of local power would require between 10 to 20 power amplifiers costing upwards of $60,000.00 just to deliver similar power to the ISP custom sound system.
The ISP custom sound systems can be designed with a wireless link with remote power at each pole or based on our HDDS “High Definition Distributed Sound” technology. In both cases the current consumption is only milliwatts with background music and not much more than a couple of amps current draw with high SPL announcements. ISP can also design an outdoor system with a unique RF link if the system requires full wireless audio transmission especially where point to point wiring is not an option.
Contact ISP Technologies directly with any questions regarding a custom designed outdoor distributed audio system.