邮件：support@plusanchor.com。反馈问题时请附上 iPhone 型号、iOS 版本和鼓的类型。
请允许麦克风权限，关闭蓝牙耳机，把 iPhone 放在鼓壳边并保持环境安静。主调音界面请在螺丝旁、距鼓圈约 3–5 厘米处干脆敲击。
一次只敲一只鼓，等待余振结束后再敲。避免 rimshot、敲到鼓圈或附近持续播放音乐。鼓心整鼓音请在“给这只鼓存一张指纹”的指纹采集中测量。
DrumTuner 提供 30 天全功能免费试用，到期后一次性购买永久版即可继续使用，不会自动扣费。首次打开 App 的页面提供“恢复购买”。试用期间，点左上角“试用剩余 N 天”，或点右上角的“…”（设置与隐私）→“试用与永久版”，都能购买永久版或恢复购买。请确认设备登录的是原购买所用的 Apple 账户。购买由 Apple 处理，DrumTuner 不接触付款资料。
鼓击与诊断数据分享可以随时关闭。你可以在 App 的“设置与隐私”中删除已上传和本机待发送的数据。详见隐私政策。
Email support@plusanchor.com. Please include your iPhone model, iOS version, and the type of drum.
Allow microphone access, disconnect Bluetooth audio devices, place the iPhone beside the drum shell, and keep the room quiet. On the main tuning screen, strike the head cleanly near a lug, about 3–5 cm from the rim.
Strike one drum at a time and let the ring die out before the next hit. Avoid rimshots, hitting the hoop, or music playing nearby. Measure the center-hit fundamental in Fingerprint Capture (Save a Fingerprint for This Drum).
DrumTuner includes a 30-day free trial of every feature. After it ends, a one-time lifetime purchase keeps the app working; you are never charged automatically. Restore Purchases is on the first screen. During the trial, tap the “days left” badge in the top-left corner, or the … button in the top-right corner (Settings & Privacy) → Trial & lifetime access, to buy lifetime access or restore it. Use the Apple Account that made the original purchase. Payments are handled by Apple; DrumTuner never sees payment details.
Hit and diagnostic sharing can be turned off at any time. You can delete uploaded and pending data from Settings & Privacy (the … button) in the app. See the privacy policy.