SV-1 SpiritVox "Ultra-Edition". Sub-Sonic & Ultra-Sonic White Noise Generator. For use in Paranormal Research, Ghost Hunting, EVP Recording & ITC research. This Special Edition of SpiritVox contains 2 signal modes to choose from: "Sub-Sonic" mode & "Ultra-Sonic" mode. EVP caught during experiment with this app: Each mode sweeps from audible to inaudible.