Guides
Step-by-step answers to the questions people ask, with screenshots.
AuCut
- How to Convert or Edit Many Audio Files at Once on iPhone Apply one tool to up to 20 audio or video files at once with AuCut: convert, change volume or speed, remove silence or noise. On your phone.
- How to Change the Speed of Audio Without Changing the Pitch Slow down or speed up a recording without changing the voice, or shift the pitch on its own, with AuCut on iPhone and Android. Offline, no upload.
- How to Make Audio Louder or Quieter on iPhone and Android Boost, lower or normalize the volume of a recording and add a fade in or out with AuCut. Offline, no account, nothing uploaded.
- How to Convert M4A to MP3 on iPhone and Android Convert M4A, MP3 and WAV on your phone with AuCut: free, offline, no sign-up, nothing uploaded. On Android it is adTrim on Google Play.
- How to Extract Audio from a Video on iPhone Without Uploading It Pull the sound out of an MP4 or MOV on your iPhone with AuCut, with no upload and no account. Extracting audio is free; save it as MP3 or M4A.
- How to Merge Audio Files on iPhone and Android Join several audio clips into one track on your phone with AuCut, trim each first, drag to reorder. Offline, no account, no upload.
- How to Remove Background Noise from a Recording on Your Phone Reduce background noise in a recording on iPhone or Android with AuCut, then compare the original and the cleaned version. Offline, no upload.
- How to Separate Audio and Video on iPhone Split a video into a silent copy that keeps its picture quality and a separate audio file with AuCut. On your phone, nothing uploaded.
- How to Split an Audio File into Parts on iPhone and Android Cut a long recording into equal parts or parts of a set length with AuCut, then share or save each one. Offline, no account.
- How to Trim Audio on iPhone and Android, Offline Cut an MP3, M4A or WAV to the part you want with AuCut: drag the ends on the waveform, fine-tune to a tenth of a second. Offline, no account.
- How to Trim a Voice Memo on iPhone Share a voice memo to AuCut, cut it to the part you want, boost the volume or add a fade, and save it as M4A, MP3 or WAV. Offline, no account.
Koedori
- How to Fix Wrong Names and Terms in a Transcript on iPhone Teach Koedori a name or term once and it fixes that word in new transcripts and rewrites your earlier notes, all on your iPhone.
- How to Make SRT Subtitles from Audio or Video on iPhone Turn audio or a video into an SRT or WebVTT subtitle file on your iPhone with Koedori: transcribed on the device, no upload, no account.
- How to Record and Transcribe a Lecture on iPhone, Offline Record a lecture and turn it into searchable text on your iPhone with Koedori: offline, no account, free for as many hours as you like.
- How to Record and Transcribe a Meeting or Interview on iPhone Record a meeting or interview and get a searchable transcript on your iPhone with Koedori: offline, nothing uploaded, no account.
- How to Transcribe a Voice Memo on iPhone Turn a voice memo or any recording into text on your iPhone with Koedori: share it from Voice Memos, offline, no account.
Noise Meter
- How to Check and Calibrate a Decibel Meter App on iPhone Check that your iPhone’s microphone responds and match it to a sound level meter with Noise Meter’s three-step calibration, under Settings.
- How to Record Your Neighbors’ Noise at Night with an iPhone Log noise from neighbors or upstairs footsteps all night with Noise Meter: decibels with the date and time, no audio recorded, no account.
Red Sheet
- Red, Green and Blue Sheet: Which Pens and Highlighters Does Red Sheet Hide? Under the red sheet red, orange and pink pen vanishes; green, pink and blue pens hide under their own sheets. See what each Red Sheet color hides.
- How to Use a Digital Red Sheet on iPhone and iPad Lay a red, green or blue sheet over photos of your own pages, or slide a band one question at a time, with Red Sheet. Free, no account.
- How to Hide Words on a Textbook Page and Make a Fill-in-the-Blank Test Box the words you want to learn on a printed page and Red Sheet hides them until you tap. Turn any page into fill-in-the-blank practice.
- How to Use Spaced Repetition on Your Own Notes on iPhone and iPad Mark each answer ○ or × and Red Sheet brings back the ones you missed the next day, with longer gaps for the ones you know. Free.
- How to Study from a PDF on iPhone and iPad, in Sync Import a PDF into Red Sheet and each page becomes a page to quiz yourself on. Sync iPhone and iPad through your own iCloud.
- How to Turn Your Notes into a Quiz on iPhone Without Typing Photograph your notes, textbook or worksheet and Red Sheet hides the answers so you can quiz yourself. Free, no account, works offline.