[ID: 1: PROTESTING SAFELY: WHAT TO WEAR: Nondescript, solid color, layered clothing; cover identifying tattoos; Heat resistant gloves; Goggles and mask; Emergency contacts written down [image shows Sharpie on arm]; Tie your hair up. WHAT TO BRING: Water for drinking and tear gas; Cash/change and ID; Bandages and first aid supplies; Snacks; Washcloth; Ear plugs; Protest signs. DON'T BRING: Cell phone without first turning off Face/Touch ID, going on airplane mode, and disabling data; Jewelry; Anything you don't want to be arrested with [images of switchblade knife and baggie of green stuff that is probably weed]; Contact lenses.
2: LRAD SAFETY FACTSHEET FOR PROTESTERS compiled by: Ron & Frosty Crunch 2020. GET OFF-AXIS FIRST. GET FAR AWAY SECOND. Folks out in the streets: this is a short guide below to staying safe from LRADs (Long Range Acoustical Device), which is a form of sonic weaponry that police have deployed in recent protests to disperse crowds. I am sharing what I know not to cause alarm, but so that people are aware of what LRADs are and can act to protect themselves, should they be deployed at any point. I am writing this as an electrical engineer working in audio and do not claim to be an expert on LRADs or sonic weaponry. This fact sheet has been cobbled together from available information online (LRAD instruction manuals, marketing datasheets, interviews, other disparate online sources) and from professional experience working in audio.
LRADs (Long Range Acoustical Device) have been deployed at actions in many major US cities. They produce high-frequency, highly directional sound to disperse crowds. Typical LRAD maximum SPLs (Sound Pressure Level) are 140dB-160dB. This is enough to burst eardrums even at a distance. The longer you are subjected to the sound, the more severe the damage to your hearing may be. Depending on proximity, permanent hearing damage is very possible.
The best safety measure is getting as off-axis and as far away as possible before it's activated. If you can't do that:
First priority is still to get as off-axis (i.e., out of its "spotlight") as you can, as far away as possible, as quickly as possible. Side-step the beam first, move away from it second. Try not to panic and abandon caution when trying to do this.
Bring earplugs, but keep in mind they alone will not be sufficient protection for prolonged periods of time. Inventor Woody Norris said in a 2008 AP interview, "What if they wear earplugs or put their fingers in their ears? The device is designed with sufficient intensity… That doesn't do a heck of a lot." Despite that, the LRAD 100x, 500x, and 1000x instruction manuals indicate that the operator (who is standing behind the beam) and people way off to the side of the beam should wear hearing protection (such as foam plugs). Having them will be better than nothing, but do not rely on them solely.
Given the high directionality of the sound, sufficiently large obstacles create effective acoustical shadows. Treat the LRAD almost like a spotlight and find large, dense cover. That said, remember that sound is a wave: it will reflect off of hard surfaces. Account for reflection when trying to take cover.
There is a video circulating suggesting signs (depending on their construction) may provide effective acoustical shielding. There are significant trade-offs and risks with this method. It should go without saying that if you block your face with a sign, you will not be able to see in front of you, leaving you vulnerable to both projectiles and to direct attacks by police. Additionally, the sign will reflect the signal, potentially at another innocent party. Bear this in mind if you are forced to use this method.
Additionally, an LRAD is not as directional as a spotlight, and depending on the model, the beam angle can be arbitrarily focused or widened. It is safest to be behind one. Since that won't be possible (that's where the police will be), getting perpendicular to the LRAD's beam (not perpendicular to the LRADS face) will also provide cover. That may also be difficult since police will likely occupy that space too. LRADs are often mounted on a pivoting stand too and can be pointed and aimed. Keep this in mind when finding cover.
{Image labeled "NYPD using an LRAD 100; larger models may be mounted on vehicles.")
LRAD Hazard Areas (from Acoustic Deterrent Systems website - a distributor of LRAD):
A diagram of the hazard areas when the LRAD is used at limited power and maximum volume. A circle around the LRAD is labeled Operator Hazard Area (Hearing protection recommended for sustained operations). A cone shoots out from the front of the LRAD in the direction of targeted subject(s), reaching 15 degrees to each side of the LRAD's aim. This cone is labeled Tone Hazard Area (Hearing damage may result in tone mode. Do not use tone if individuals are within Tone Hazard Area. Use voice mode only.). In this case, the cone shoots 10m out from the LRAD.
Another diagram illustrates the hazard areas when the LRAD is used at maximum power and maximum volume. A half-circle behind the LRAD is labeled Operator Hazard Area (Hearing protection recommended for sustained operations). A half-circle in frong of the LRAD and a beam 40 degrees to either side of the direction of targeted subject(s) reaching out ~15m is labeled Voice-Tone Hazard Area (Hearing damage may result in both tone mode and voice modes). A narrower but longer cone shoots out from the front of the LRAD in the direction of targeted subject(s), reaching 15 degrees to each side of the LRAD's aim. This cone is labeled Tone Hazard Area (Hearing damage may result in tone mode. Do not use tone if individuals are within Tone Hazard Area. Use voice mode only.). In this case, the cone shoots 75m out from the LRAD.
Tone Beam Width: 38m at range of 75m, 25m at range of 50m, 5m at range of 10m.
Chart of typical sounds by decibels and their impact:
No sound perceptible to human ear (0dB) - threshhold of hearing.
Normal breathing (10dB).
Whisper (20dB).
Library / Quiet office / Watch ticking (30dB).
Quiet residential/rural area (40dB).
Quiet suburban area / Rainfall / Fridge (50dB).
Dishwasher / Air conditioner (60dB) - Normal conversation.
Highway traffic / Vacuum cleaner (70dB).
Alarm clock / Doorbell / Ringing phone (80dB).
Noisy restaurant / Heavy traffic (85dB) - Maximum permitted level in workplace (8 hours).
Tractor / Bus or truck (90dB).
Electric drill / Underground train (95dB - Sustained exposure may result in hearing loss.
Motorbike / Walkman (max. volume) (100dB).
Disco / Pneumatic drill / Car horn (110dB).
Chain saw / Rock concert / Stadium (115dB).
Jet plane taking off / Thunder (120dB) - Threshhold of pain.
Vuvuzela horn (world cup) (127dB).
Power drill / Orchestra percussion (130dB).
Air-raid siren (135dB).
LRAD-100X max (137dB).
Firearms / Gunshot (140dB) - Brief exposure can cause permanent damage.
LRAD-300X max (143dB).
LRAD-500X max (149dB).
Artillery fire (at 500 ft / 150m) (150dB).
LRAD-1000X max (153dB).
Balloon pop (at 3 ft / 1m) (157dB)
LRAD-2000X max (162dB).
Rocket launch (180dB) - Death of hearing tissue.]