How to revise from recorded lectures in three passes

Do the arithmetic before you book the time

Open the recordings list and count. Twelve lectures at fifty minutes each is 600 minutes, which is ten hours. One listen at 1.5× is 600 ÷ 1.5 = 400 minutes, six hours and forty minutes. That one listen is the most the plan below ever plays of a whole lecture. Replaying everything a second and a third time is what eats three weeks, and it leaves you nothing to test yourself on.

Now cost the plan. The first pass is that one listen: 400 minutes across twelve lectures at 1.5×, about 19 minutes a day over three weeks. After it, everything runs on the marks. Three marks per lecture, two minutes of audio around each mark, is 3 × 2 = 6 minutes per lecture. Across twelve lectures that is 6 × 12 = 72 minutes. At 1.5× those 72 minutes come to 48. Spread across three weeks that is four lectures a week: 24 minutes of audio at normal speed, 16 at 1.5×. Redo the sum with your own lecture length and your own speed; the playback speed calculator on this site does the division if your lectures run ninety minutes or you listen at 1.25×.

The 72 minutes is the second pass’s audio only. Writing the questions and answering them takes longer than listening does, which is the point. This page covers the three weeks between a pile of recordings and an exam. Getting clean audio in the first place belongs to the lecture recording guide, and the cue-and-summary layout belongs to the Cornell template page.

Three passes over the same fifty minutes

Each pass has one job, and the jobs interfere. A re-listen turns into three hours when you try to mark, summarize, and test at once. So the first pass may not write notes, the second may not play the whole lecture, and the third may not look at anything.

Mark the seconds first. Write the questions second.

The first pass is the cheap one. Keep your hands off the keyboard and let it run.

1. Play the recording at a speed you can follow. Every time you lose the thread, hear a figure you did not write down, or hear something the slides do not carry, note the clock time. Nothing else goes on paper.
2. Stop at three marks. A fourth is usually the same confusion as the second. If a lecture produces none, write 00:00 and move on; that hour is not where your three weeks should go.
3. Record the times as minutes and seconds, exactly as the player shows them. 08:40 sends you to one place. “Somewhere near the start” sends you nowhere.

The second pass is where the reading happens. Open the sheet from the first pass and work down the three times.

1. Play about two minutes around the mark: roughly thirty seconds before it and ninety after. The sentence you missed usually arrives before the moment you noticed you had lost it, which is why the window opens earlier than the mark.
2. Write one question the passage answers. A question, with an answer that can be right or wrong. “Which two ions does the sodium-potassium pump move, in which directions, and in what ratio?” can be graded. “Membrane transport” cannot.
3. Leave the answer off the sheet. Three questions and three timestamps is the whole of it. Writing the answer now is how you end up recognizing your own handwriting instead of recalling the material.

Scrubbing back to 08:40 with a thumb is the slow part. If the lecture is in Voice Memos and a transcript has been made, selecting a word in the transcript moves the playhead to that point, so you can find the sentence by its words. Apple lists conditions on that transcript: iPhone 12 or later, one of the languages on its support page, and it is not available in all countries or regions. Checked against Apple’s page on 2026-09-20.

One page per lecture, filled across the three passes

One sheet, one lecture. The timestamps go on in the first pass, the questions in the second, the results and the next date in the third. Copy it, print it, and keep the stack in lecture order.

LECTURE REVIEW SHEET (one page per lecture)

COURSE:
LECTURE NUMBER / TITLE:
RECORDED ON:
RECORDING LENGTH:

MARK 1   time __:__
  Question:
  First attempt:   right  /  half  /  blank
  Replay from __:__ (the mark minus 0:30) for 2 min

MARK 2   time __:__
  Question:
  First attempt:   right  /  half  /  blank
  Replay from __:__ (the mark minus 0:30) for 2 min

MARK 3   time __:__
  Question:
  First attempt:   right  /  half  /  blank
  Replay from __:__ (the mark minus 0:30) for 2 min

STILL BLANK AFTER THE REPLAY:

THIRD PASS DONE ON:
NEXT REVIEW DATE:
  right = one week   half = three days   blank = the next day
  Count from the third-pass date, and use the shortest interval
  any mark on this sheet earned.

LECTURE REVIEW SHEET (one page per lecture)

COURSE: Cell biology
LECTURE NUMBER / TITLE: 7, Membrane transport
RECORDED ON: 9 October
RECORDING LENGTH: 50:12

MARK 1   time 08:40
  Question: What separates facilitated diffusion from active transport?
  First attempt:   half
  Replay from 08:10 (the mark minus 0:30) for 2 min

MARK 2   time 23:05
  Question: Which two ions does the sodium-potassium pump move,
  in which directions, and in what ratio?
  First attempt:   blank
  Replay from 22:35 (the mark minus 0:30) for 2 min

MARK 3   time 41:18
  Question: Why does the pump stall when ATP runs out while
  diffusion keeps going?
  First attempt:   right
  Replay from 40:48 (the mark minus 0:30) for 2 min

STILL BLANK AFTER THE REPLAY:
The ratio. Three sodium out, two potassium in, per ATP. Slide 22.

THIRD PASS DONE ON: 12 October
NEXT REVIEW DATE: 13 October
  Mark 2 was blank, so the next day wins over the three days
  Mark 1 earned and the week Mark 3 earned.

Twelve of these is a stack you can carry. A week before the exam, sort them by the number of blanks, and the order of your last week writes itself.

Third pass: answer with everything closed

Fold the sheet so the timestamps and results are hidden and only the three questions show. Shut the slides, the textbook, and the player. Say each answer out loud or write it, then grade it.

• Right means you produced the whole answer before you checked anything. Recognizing it after the fact does not count.
• Half means the shape was there and a number, a name, a direction, or a condition was missing. Write down which one.
• Blank means nothing came. Open the recording at the timestamp on that line and play the two minutes again, now knowing exactly what you are listening for.
• Set the next date before you put the sheet down, counting from the day you did this third pass: a week for a right, three days for a half, the next day for a blank. Those three intervals are this sheet’s convention rather than a research finding, and they are there so the decision is already made when you are tired. Where the three marks disagree, the shortest one wins, because the sheet comes back as one page.

Recalling material from memory has an evidence base; The Learning Scientists, a group of cognitive psychology researchers, set out what the effect is and how it differs from rereading. That evidence belongs to the method, and a particular app does not inherit it. Whether 1.5× suits your material is a separate question, and the arithmetic above counts minutes rather than answering it.

If the lecture is already a note in Phrase, the audio stays attached with a timestamped transcript, so a blank on the sheet goes back to the second where the point was made rather than to the top of the file. Once the questions are checked, the same note can produce flashcards, a quiz, or a mind map. AI features are included with Pro, and the current allowance is shown in the app.

Choosing between the three is its own decision, and the study tools page sets out what each format produces from a reviewed note.

Questions readers ask

How do you study recorded lectures without replaying all of them? You listen once for marks, then only around the marks. After that one listen, ten hours of recordings shrink to 72 minutes of audio, three two-minute windows per lecture. The time you save goes into answering the questions, which is the part that shows you what you do not know.

Does this work for video lectures? Yes, with one change. Mark the slide number next to the timestamp, because a video answers some questions visually and a diagram is faster to check than ninety seconds of audio. Everything else holds: three marks, one question each, closed-book on the third pass.

Should you turn lecture notes into flashcards instead? The two fit together. This sheet decides which passages deserve cards, and the cards come from questions you already failed once. Writing cards for a whole lecture front to back produces a deck full of things you already knew. The flashcard guide covers how to word a card and check its answer.

Can AI turn lectures into flashcards for you? It can draft them from a transcript, and the draft still needs a pass from you. A model working from a transcript cannot tell which sentence you personally lost. Your three marks can. Draft with the transcript, keep the cards that match a mark, and check the wording against the recording.