String jump is what happens when an animal that was standing at 25 yards is no longer standing where it was by the time the arrow arrives. It is not myth. It is not bad shooting. It is a neurological event the animal executes involuntarily in response to acoustic stimuli it cannot ignore, and it is almost entirely outside the hunter's ability to prevent. Understanding why it happens does not make it go away — but it does clarify what is actually occurring, and it settles the debate about which sound is responsible.
Both sounds are responsible. The question is not which one — it is what each one does.
The two sounds and what they are
A compound bow at the shot produces two acoustically distinct events separated in time.
The first is the launch sound — the crack, snap, or thump of the bow firing. This is a broadband impulsive sound generated by multiple simultaneous sources: string acceleration and deceleration, cam rotation through the shot, limb oscillation as stored energy releases, and the hardware resonance of the entire riser assembly. On a well-dampened modern hunting bow this sound is reduced but not eliminated. It is still an impulsive transient — a sudden onset sound — which is exactly the category of sound animal auditory systems are most sensitive to. The launch sound radiates in all directions from the bow.
The second is the arrow-in-flight sound — the sustained acoustic signature of a moving arrow. This is generated primarily by the vanes or feathers cutting through air as the arrow rotates and translates toward the target. It builds from silence as the arrow leaves the bow and grows louder as the arrow approaches, with a distinct directional character pointing straight at whatever the arrow is heading toward. It is not a crack — it is a whoosh, a buzz, or a whistle, depending on the vane style and arrow speed. Unlike the launch sound, this sound has a clear approach vector and grows in amplitude over time.
Sound travels at approximately 1,125 feet per second at sea level. A fast hunting arrow travels at roughly 280–320 feet per second. The launch sound — generated at the bow, at the hunter's position — always reaches the animal before the arrow does. There is no bow setup in existence where the arrow beats the launch sound to the target.
The arrival sequence and what it means
The numbers matter. At 20 yards, a 300 fps arrow takes about 200 milliseconds to reach the target. Sound covers the same 20 yards in roughly 53 milliseconds. That means the deer receives the launch sound approximately 147 milliseconds before the arrow arrives. Add an estimated 50–70 milliseconds of neurological processing time before muscle action begins, and the animal still has 80 to 90 milliseconds of active movement time before impact. At 40 yards, that window opens to more than 230 milliseconds. A deer dropping its body can descend 8 to 12 inches vertically in that time.
The launch sound is not just a warning — it is the event that puts the animal into motion. But a closer look at the neuroscience reveals that the launch sound alone is not what produces the explosive, full-body evasive maneuver that hunters describe. To understand why, you have to understand what two sequential acoustic stimuli do to an animal's nervous system.
Alert versus escape — two different neurological states
Animal nervous systems distinguish between two categories of threat response. The first is the orienting response: a sudden novel stimulus causes the animal to freeze, orient its senses toward the source, elevate its arousal level, and scan for additional information. Heart rate elevates. Pupils dilate. Muscles prime for action. This is not an escape event — it is a threat-assessment event. The animal is gathering information before committing to a direction.
The second is the escape response: a confirmed incoming threat that has been localized triggers a full, explosive motor program. The animal does not decide to run. The motor program executes automatically — the hind legs drive the body down and then propel it laterally and forward in a single integrated burst. This is the crouching drop and bound that hunters see. It is fast, stereotyped, and largely involuntary.
The key distinction is what triggers each state. A sudden impulsive sound — the bow — triggers the orienting response. The animal goes on alert. It is now in a state of heightened arousal, fully sensitized to the next input. What it receives next is the arrow: a growing, directional sound approaching from the exact direction the animal just oriented toward, building in amplitude over the roughly 150 milliseconds of the arrow's flight. That is not an ambiguous stimulus. It is a confirmed incoming threat from a known vector. The aroused animal in the orienting state responds with the escape response — the drop and bound.
Why neither sound alone produces the same result
The two-stimulus cascade matters because it predicts what happens when you remove either element — and those predictions are consistent with what hunters observe in the field.
Bow sound alone, with a silent arrow: The animal hears the launch sound and enters the orienting response. It freezes, orients, and goes on high alert. Without the arrow's growing in-flight sound — without any confirmed incoming object — there is no second stimulus to trigger the escape motor program. The animal may hold, scan, flag its tail, or begin to move cautiously, but the full explosive drop-and-bound response is not triggered. It knows something happened nearby. It does not know something is hurtling toward it.
Silent bow, with only the arrow sound: The animal is at baseline arousal when it suddenly hears a directional whoosh growing rapidly from one side. This is a genuinely confusing stimulus. There was no warning. There is no context. An arrow sound without a preceding bow sound is an event without a category in the animal's threat library — it is not a predator, not a footstep, not a branch snap. The animal may freeze in confusion rather than execute a clean escape response. A primed escape system is not in place, because the alerting stimulus never arrived.
Both sounds in sequence: The bow fires. The animal hears the launch crack, orients instantly toward the hunter's position, and enters a maximally aroused alert state within 50 to 70 milliseconds. The arrow's sound — growing from exactly the direction the animal is now oriented toward — arrives at a nervous system running at peak sensitivity and confirms an incoming threat from a known vector. The escape response fires. The deer drops and bounds. This is string jump.
The mechanism is not the bow sound triggering a jump. It is not the arrow sound triggering a jump. It is the bow sound priming the system and the arrow sound pulling the trigger on a system that is already cocked. Remove either element and the cascade does not complete with the same speed or amplitude.
What the deer actually does — and why the arrow misses
String jump is misnamed. The deer does not jump upward. It drops. At the sound onset, the deer's hindquarters lower rapidly as the hind legs load for the bound. The center of mass drops 6 to 12 inches before the animal drives forward. An arrow aimed for the center of the heart-lung zone — where an ethical hunter aims — passes through the space where the deer was. Depending on the distance and the degree of the drop, the arrow hits the lower body wall, the liver, the gut, or passes under the deer entirely.
At 20 yards, the deer has roughly 80 to 90 milliseconds of active movement before the arrow arrives. A deer dropping at a modest rate can descend 4 to 6 inches in that window. At 30 yards, the window is closer to 150 milliseconds and the drop is 7 to 10 inches. At 40 yards, 230 milliseconds and 10 to 14 inches. The ethical aiming point at 20 yards and the ethical aiming point at 40 yards are, for the same deer, at different effective locations because of string jump.
What you can control — and what you cannot
There is no compound bow setup that eliminates the launch sound to the degree that it fails to trigger the orienting response in a deer standing 20 to 40 yards away. String silencers, limb dampeners, and internal dampening systems reduce the launch noise and are worth using — not because they prevent string jump, but because they reduce the sharpness of the first stimulus. A less impulsive, lower-amplitude launch sound is a weaker alerting stimulus. It may not fully complete the orienting response — may not push the animal into maximal arousal — which means the arrow sound lands on a slightly less primed system.
Arrow speed does not solve the problem for the same reason. A faster arrow covers the distance in less time, but the launch sound still arrives at the deer well before the arrow does regardless of arrow speed. Closing the gap between the two arrivals requires arrow speed approaching the speed of sound — roughly 1,125 fps — which is not achievable with current archery equipment. A 320 fps arrow arrives at 20 yards in 188 milliseconds instead of 200. The orienting response window barely changes.
What does change is the in-flight sound exposure time. A faster arrow spends less time in flight, which means the animal hears the arrow sound for fewer milliseconds before impact. A very fast arrow at close range may not give the animal enough time to complete the full escape motor program even after the response is triggered. This is the real argument for speed at close hunting distances — not beating the launch sound, but compressing the escape execution window.
The most effective practical mitigation is not gear — it is shot timing and distance management. A deer with its head down feeding, attention divided, is not on alert. The orienting response requires attentional resources. An animal already distracted may have a slower, weaker orienting response to the launch sound, which produces a weaker or slower cascade. Shot timing toward feeding, relaxed animals at close distances is the only strategy that consistently compresses the string jump window on both ends: shallower orienting response to sound one, shorter flight time compressing the window before sound two completes the trigger.
Why the debate keeps going
The argument over bow sound versus arrow sound persists because hunters are trying to isolate a two-stimulus event by testing one variable at a time. A hunter who installs a quiet bow and still sees string jump concludes: "it must be the arrow sound." A hunter who hears about silent arrows (suppressed bow with no vane sound) and assumes the deer didn't jump concludes: "it must be the bow sound." Both are seeing part of the answer and calling it the whole thing.
The evidence from either camp is consistent with the two-stimulus model. Reduce the bow noise significantly enough and the orienting response weakens, which means the arrow sound triggers a slower, less complete escape — the deer still moves, but less dramatically. Suppress the arrow sound significantly and the escape response loses its second trigger — the deer is on alert but does not execute the full drop. Neither result eliminates the event. They each disrupt one half of a two-part system.
The only scenario that would truly prevent string jump is one where neither stimulus registers above the animal's threat threshold: a bow so quiet that the launch fails to trigger a full orienting response, and an arrow so silent in flight that it fails to confirm an incoming threat to a primed nervous system. That combination does not currently exist. Until it does, the deer will move.