SSS.6.33 - Research Supplement: 30 Caliber Hunting Silencers - First Round Pop (Members Only)
/Dead Air Sandman-K, YHM Resonator K, Rugged Razor, Q Trash Panda, Rugged Radiant, SilencerCo Omega 300, CGS Hyperion K, and CGS Helios QD on a .308WIN Bolt Action Rifle with 20-inch Barrel
Eight silencers evaluated by PEW Science are included in this members-only Research Supplement to examine relative First Round Pop (FRP) performance characteristics. The silencers in this group were selected for their applicability and market popularity for use as hunting silencers; silencers possessing length and/or weight characteristics making them conducive to field use on bolt-action rifles. The CGS Helios QD, although heavier than the other models, is included in this evaluation due to the future applicability of its FRP data. The release of a titanium Helios QD is expected from the manufacturer this year.
This is not an exhaustive list of so-called hunting silencers on the current market, but is a relatively varied representation of available current technology in the size and weight regime of interest. The published public Sound Signature Reviews of the silencers with supersonic ammunition are linked below:
Length and weight characteristics of .30 silencers typically influence field use when hunting game; for many types of hunts, sound signature performance characteristics are also paramount to the user. FRP performance, specifically, dictates the suitability of a silencer due to the short firing schedule required for harvesting medium and large game. Single shots are often used by hunters with follow-up shots being the exception; not the norm. Therefore, suppressed small arm weapon systems used in the field must be able to exhibit acceptable performance immediately, filled with oxygen from the atmosphere, at ambient temperature.
Section 6.33.1 provides an overall summary of FRP performance at the muzzle and ear.
Section 6.33.2 provides detailed comparisons of the sound signatures measured at the muzzle.
Section 6.33.3 provides detailed comparisons of the sound signature measured at the shooter’s ear; the characteristics often most important to a hunter.
Section 6.33.4 presents some concluding thoughts.
This research supplement is intended to provide more information to PEW Science members with regard to specific sound signature characteristics of the tested configurations in the aforementioned reviews and to help frame objective loudness comparisons between the eight silencers in the FRP signature regime. This supplement is part of ongoing PEW Science small arm weapon system sound signature research.
6.33.1 FRP Performance Overall Summary
FRP performance correlates with overall Suppression Rating. However, there are exceptions. Normalized FRP performance is compared in Figure 1, below. Note that the maximum human inner ear damage potential of the silencer with the loudest measured FRP (the Sandman-K) is used in the normalization. This allows strict relative comparison of all the silencers shown.
The data should be viewed with the following Muzzle behavior outliers in mind:
The Rugged Razor has a lower overall Muzzle Suppression Rating than the Resonator K. However, its FRP at the muzzle is quieter.
The Omega 300 has a higher overall Muzzle Suppression Rating than the Hyperion K. Nonetheless, its FRP at the muzzle is louder.
At the Shooter’s Ear, there are no trend outliers in this dataset; all silencers in this group with lower at-ear Suppression Ratings exhibit louder FRP. The data in the table is sorted by Muzzle FRP, from quietest (Helios QD) to loudest (Sandman-K). The silencer with the quietest Ear FRP is also the Helios QD, with the Omega 300 being slightly louder. The Sandman-K also has the loudest FRP at the ear.
As noted in the table, the relative the Muzzle and Ear FRP measurements shown are not comparable to one another. Muzzle numbers should be compared with muzzle, and ear with ear. This is a consequence of the chosen normalization and the hearing damage potential with the Sandman-K at the muzzle and ear being different (as with any silencer).
Fig 1. Normalized FRP Performance Summary (Supersonic .308 Bolt-Action Rifle)
The data shown in Figure 1 is intended to present the likely human relative perception of FRP magnitude of the silencers to both bystanders and the shooter. It is important to note that the human inner ear responds differently to certain frequencies. On average, it is postulated that the relations in Figure 1 will directly correlate to human inner ear response. However, some users may have hearing sensitivity that is compromised or different than others in certain frequency ranges. The following subsections of this Research Supplement present in-depth comparisons of human inner-ear modeling response to the FRP signatures.
6.33.2 Comparisons of Muzzle Waveforms Measured in the Free Field
It is not always possible to determine relative, objective loudness from only the measured average peak sound pressure amplitude and measured peak sound pressure momentum transfer potential (impulse). Therefore, the Suppression Rating also considers physical ear response to measured sound signatures. The human inner ear responds to different sound pressure frequencies with varying sensitivity. Physically, these frequencies excite different regions of the basilar membrane within the cochlea. The human ear is typically most sensitive to sounds that excite the membrane near a frequency of 4,000 Hz. However, the ear may be exercised, and therefore damaged, at different physical regions. It is postulated that this inner ear response directly correlates to the perceived loudness of suppressed small arms.
PEW Science Research Note: As stated in previous Research Supplements, it is important not misconstrue the frequency-domain data in this Research Supplement with a simple frequency analysis (Fourier transform) of the time-domain overpressure waveforms presented in the reviews. The data shown in this research supplement is the output from analytical human inner ear modeling with the measured test data used as free-field overpressure loading input.
6.33.2.1 FRP Muzzle Comparisons
Figure 2 presents the results of an inner ear analysis performed using measured sound overpressure waveforms from the first shots in the referenced tests. The curves show normalized physical response of the human inner ear as a function of basilar membrane location within the cochlea and corresponding sensitivity frequencies. Fig 2a shows the response on the vertical axis with a linear scale. Fig 2b and Fig 2c show the same data on a logarithmic scale, in the low and high frequency hearing response regimes, respectively. Note that the data is normalized; this lets you see the relative theoretical ear response for the silencers. To personnel located 1.0 m left of the weapon muzzle, the CGS Helios QD is postulated to sound the quietest, with the Sandman-K being the loudest.
Note that In the low frequency response regime, the Trash Panda signature is less intense, while the Razor seems to excite the ear with higher response, resulting in a possibly “lower tone” perception to a bystander.
In the mid to high frequency regimes, where the human inner ear exhibits the greatest sensitivity, the Helios QD is the quietest at the muzzle during the first shot, but at the highest frequency sensitivity, the Hyperion K is the quietest. The Razor has a peak ear response characteristic that exhibits high frequency bias when compared to that of the Trash Panda, which may negate the aforementioned “lower tone” relative perception in the lower frequency ranges.
Fig 2a. Comparison of FRP Human Inner Ear Response - .308 at the Muzzle (Linear Scale)
Fig 2b. Comparison of FRP Low Frequency Human Inner Ear Response - .308 at the Muzzle (Log Scale)
Fig 2c. Comparison of FRP High Frequency Human Inner Ear Response - .308 at the Muzzle (Log Scale)
PEW Science Research Note: It is postulated that the first shot with the Helios QD will most likely be perceived to be quietest to bystanders, with the Hyperion K and Omega 300 sounding similar in overall loudness, with the Radiant being slightly louder. The Sandman-K is postulated to be much louder than all of the other silencers with the Trash Panda edging out the Razor in performance and the Resonator K bridging the gap between the Razor and Sandman-K.
6.33.3 Comparisons of Waveforms Measured near the Shooter’s Ear
The sound signatures measured at the ear during the tests of each silencer are significantly different than those measured at the weapon muzzle and this difference is not only shown in the average peak sound pressure and impulse measurements, but also with inner ear analysis.
6.33.3.1 FRP Ear Comparisons
Figure 3 presents an inner ear analysis performed using measured sound overpressure waveforms at the shooter’s right ear from the first shots in all tests. Fig 3a shows the response on a linear vertical scale. Fig 3b and Fig 3c show the same data on a logarithmic vertical scale, in the low and high frequency hearing response regimes, respectively. To personnel firing the weapon, the Helios QD is again the quietest silencer during the first shot. The Omega 300 exhibits quieter FRP performance at the shooter’s ear than the Hyperion K.
The Radiant has a high-frequency bias at the shooter’s ear when compared to the Trash Panda (similar to how the Razor did, at the muzzle) and the Resonator K also seems to exhibit high frequency bias at the shooter’s ear. These inner ear frequency response components may indicate that the the Radiant and Resonator K may be perceived by shooters to sound harsher on the first shot, than the Trash Panda and Razor, respectively.
Fig 3a. Comparison of FRP Human Inner Ear Response - .308 at the Ear (Linear Scale)
Fig 3b. Comparison of FRP Low Frequency Human Inner Ear Response - .308 at the Ear (Log Scale)
Fig 3c. Comparison of FRP High Frequency Human Inner Ear Response - .308 at the Ear (Log Scale)
PEW Science Research Note: Overall, the relative FRP performance perception to the shooter correlates with at-ear Suppression Rating in this group of silencers, especially at higher frequency inner ear sensitivity regions. Personnel exhibiting some high frequency hearing loss may perceive silencers such as the Hyperion K and Trash Panda to be quieter than other silencers that may seem louder to most shooters; individual hearing sensitivity differing from 95th percentile human physiology may skew the postulated perception outcomes.
6.33.3 Research Supplement Summary
Overall Summary: The Helios QD, if (when) offered with a lighter weight, will most likely be the de facto choice for the discerning shooter looking for the quietest overall silencer in the “hunting/compact” category with excellent FRP performance. The Helios QD, Omega 300, and Hyperion K exhibit superior FRP performance in this class.
In the mid to high frequency regimes, where the human inner ear exhibits the greatest sensitivity, the Helios QD is the quietest at the muzzle during the first shot, but at the highest frequency sensitivity, the Hyperion K is the quietest. The Razor has a peak ear response characteristic that exhibits high frequency bias when compared to that of the Trash Panda, which may negate the aforementioned “lower tone” relative perception in the lower frequency ranges.
To personnel firing the weapon, the Helios QD is again the quietest silencer during the first shot. The Omega 300 exhibits quieter FRP performance at the shooter’s ear than the Hyperion K. The Radiant has a high-frequency bias at the shooter’s ear when compared to the Trash Panda (similar to how the Razor did, at the muzzle) and the Resonator K also seems to exhibit high frequency bias at the shooter’s ear. These inner ear frequency response components may indicate that the the Radiant and Resonator K may be perceived by shooters to sound harsher on the first shot, than the Trash Panda and Razor, respectively.
This supplement is part of ongoing PEW Science small arm weapon system sound signature research. PEW Science thanks you for your support.
