We have developed self-control, pseudo-active noise absorption structural (SPNAS) mechanism that selectively absorbs wideband noise up to 40 dB without any electrical sensors/controls. Our structure is a prescribed combination of an acoustic self-control mechanism as an add-on to a target noise system, consisting of two innovative noise mechanisms (patent pending). Both noise absorption mechanisms are strategically arranged to absorb target-specific spectral bands.
acoustic signatures reduction of small rifles
Our proprietary technology was used to reduce acoustic signatures of small rifles (e.g., M4) by applying the SPNAS mechanism on the outer surface of the barrel (replacing the handguard) and to demonstrate two distinct performance milestones: 1) overall firing noise reduction up to 19 dB in 200 – 2000Hz and peak reduction up to 40 dB at high frequencies on the firing line (behind the muzzle) and, 2) an acoustic signature “edit” in terms of peaks-shift by 10s up to 100s Hz in the frequency spectrum during projectile flight (downrange) by using a simple, but precise, gas deflection phenomenon on a projectile.
We named the technology for the rifle acoustic signature Multi-modal Active Noise Control for Ammunition (MANCA). The smart SPNAS mechanism does not interfere with projectile movement or affect gas discharge inside the barrel because the SPNAS is acoustically coupled to the barrel’s outer surface as a simple add-on. IHIO Innovations team has verified through the MANCA project that the SPNAS can absorb and suppress an extreme amount of impulsive muzzle noise with a simple add-on structure.
Muzzle Noise Reduction (patent pending)
The finite element analysis result demonstrates the noise reduction effect of the IAC unit on the sound pressure level propagating through the air medium at a high frequency of 4100 Hz. The figures show sound pressure level (dB) contour plots of the M4 barrel only without IAC (Left) and the M4 barrel with the IAC unit in the surrounding air medium at 4100 Hz frequency. The results demonstrate the effect of the IAC unit in suppressing the sound pressure level propagating in the air medium.
Acoustic Signature Edit for rifles
Our technology is based on IHIO’s proprietary, self-controlled, pseudo-active acoustic structures as an add-on to a rifle barrel and a bullet projectile without any electrical sensors/controls or invasive silencers. At the current design stage, we have demonstrated two distinct performance milestones: 1) overall noise reduction up to 19 dB in the 600 – 900 Hz band and a peak reduction of 40 dB at 1390 Hz on the firing line (behind the muzzle) by adding pseudo-active acoustic structures to the barrel and, 2) acoustic signature “edit” in terms of peaks-shift by 10s up to 100s Hz in frequency spectrum during projectile flight (downrange) by modifying projectile dynamics.