Why the sound, not the idea, is the problem
Marker training works because a short, distinctive sound tells the dog the exact behaviour that earned the reward. But for a noise-sensitive dog, a box clicker's sharp snap — designed to carry across a training field — lands as a startling crack at close range, especially indoors. If his first clicks were followed by food but delivered at full volume beside his ear, he may now flinch at the sound itself while still loving the training game. There is nothing to push through here: a marker the dog dreads cannot mark anything usefully, and every flinch pairs your training sessions with a small fright.
Test softer sounds before you train anything
Find his version of the click before teaching a single behaviour. Try, at a distance and with food ready, a clicker clicked inside a pocket or wrapped in a folded cloth, a retractable pen, a tongue click, or a quiet, consistent word such as yes spoken in an even tone. Watch his body, not his obedience: ears forward and a look toward the food means the sound is acceptable, while flinching, lip-licking, turning away, or leaving means it is not, however faint you thought it was. Some dogs accept a muffled clicker happily within a session or two of pairing; others will always prefer a verbal marker, and that is a perfectly good outcome.
Pair the chosen sound until it genuinely predicts food
This stage — often called charging the marker — is deliberately dull. In a quiet room, make the soft sound, pause a beat, deliver a pea-sized piece of something he adores, and repeat ten to fifteen times across a couple of short sessions. He should start glancing expectantly toward the food hand at the sound; that brightening is the association forming. If you are using a muffled clicker, unwrap one layer of cloth every few sessions only while his reaction stays cheerful, and stop unwrapping well short of any volume that makes him hesitate. Never use the sound to call him, correct him, or get his attention during this stage — it has one meaning only: that exact moment earned a reward.
Use the marker for easy wins first
Once the sound makes him brighten, spend it on behaviours he already finds easy — looking at you, a hand touch, stepping onto a mat — so he learns the rhythm of sound, reward, repeat without the pressure of new skills. Keep sessions to a few minutes in the quiet room where you charged the marker before using it in the garden or on walks, where background noise will tempt you to click louder. If you chose a verbal marker, keep the word identical and oddly specific; a word he hears all day in conversation cannot do the job, which is why a short, consistent yes reserved only for training works better than his name.
When sound sensitivity is the bigger story
A dog frightened by a click may be broadly sound-sensitive — reacting to cutlery, doors, or household appliances — or may have ear pain making sharp sounds genuinely hurt. If he startles at many everyday noises, shakes his head, scratches at an ear, or his sensitivity is new, see your veterinarian before building a training programme around sounds. A behaviour professional can also help design a wider confidence plan if household noise is shrinking his world. If a new sound sets her back, put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library, which gives you another rung for the ladder without guessing.