Published by PitchChanger · Updated · How these guides are made
Hear the difference
Original synthesized diagnostic material, authored at 48 kHz, 16-bit PCM. These are controls for the worksheet, not measurements of this tool or real instruments.
Pause your workspace preview before comparing these clips.
Start quietly. Download the WAV files for external comparison; no listening outcome is asserted.
How to use this workflow
Record the actual speed
Use a constant speed setting and note any trim offset. A tempo map or inserted silence requires a different mapping.
Map several landmarks
Calculate the start, a middle event and the ending. Check the saved file for any additional offset.
Compare matching context
Choose the same number of notes around each event, even when the elapsed seconds differ.
Four-second source at 75% speed
A 4-second source at r = 0.75 has a calculated output duration of 5.333333 seconds before frame rounding and implementation boundary behavior. Attack begins at source 1.000 s, so its mapped position is 1.333333 s. Source 3.000 s maps to 4.000 s.
If you first remove 0.5 s from the source, subtract that trim offset before dividing: the original 1.000 s event now maps to (1 − 0.5) / 0.75 = 0.666667 s. Applying the untrimmed map would place the comparison on the wrong event.
Swipe or scroll sideways to read all columns.
| Checkpoint | Action or value | Interpretation |
|---|---|---|
| Source 1.000 s | 1 / 0.75 = 1.333333 s | Untrimmed mapping |
| Source 3.000 s | 3 / 0.75 = 4.000 s | Middle landmark |
| Trim 0.5 s first | 0.5 / 0.75 = 0.666667 s | Offset before scaling |
Know when the simple mapping stops working
Reordering, deleted middle sections and effect tails break a single global duration ratio. Map each retained source segment separately. Do not stretch a reverberant ending to align it with a dry file’s end and then call the resulting difference a processing defect.
The speed changer does not provide synchronized dual-file audition or a tempo map. Export versions, keep source boundaries and compare in an external editor when precise alignment matters. The Attack download supplies a reproducible landmark, not an observed export latency.