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The two signs look nearly identical (an arc), but mean entirely different things. Confusing them is the commonest reading error among beginners.
A tie joins two notes of the same pitch into one. A slur connects several notes of different pitches.
A table to keep them apart
| Tie | Slur | |
|---|---|---|
| Notes joined | must be the same pitch | different pitches |
| Effect | values added, in practice one note | every note sounds, but connected |
| Use | extending a value across beats or bars | articulation (legato), one syllable over several notes in vocal music |
| Number of notes | usually two | may cover many |
How to tell: look at the pitch
One test only:
Same pitch at both ends of the arc means a tie; different pitches mean a slur.
| Notation | Verdict | Actual effect |
|---|---|---|
♩~♪, both C | tie | a single C lasting 1.5 beats |
C~D, different | slur | both notes sound, played legato |
So on meeting an arc, the first question is not how long it is but what notes it joins.
What each is for
Ties (recall note values):
| Case | Why needed |
|---|---|
| a note crossing a bar line | the bar line must be preserved (it marks the accent, see [[concept:meter |
| a note crossing a beat | keeps the beat grouping visible |
| all pitches equal | the precondition for a tie |
Slurs:
| Case | Meaning |
|---|---|
| instrumental | legato — no break between notes |
| vocal | one syllable over several notes |
| wind / strings | indicates where to breathe and how to group a bow |
The third row is practical: a wind player reading a slur knows that passage must be played in one breath, and a string player decides how many notes go in one bow (see articulation and breathing and phrasing).
One case that is easily misread
Two adjacent notes of the same pitch inside one bar:
| Written as | Meaning |
|---|---|
| one note with a longer value | one note |
| two notes plus a tie | one note (values added) |
| two notes plus a slur | two notes (both sound, played legato) |
The difference between rows two and three is whether the pitches are equal. If the pitches are equal and you read it as a slur, you will play the note twice — a very audible error on piano.
On piano and strings, equal pitches joined by a tie sound once: do not re-strike the key or change bow.
Diagram: one arc, two meanings
Listen: one attack or two
This site cannot show a staff, but it can play a repeated note twice against one sustained note — exactly the aural difference between reading an arc as a slur and as a tie.
Common misconceptions
- "The two signs are the same." Entirely different: one adds durations, the other marks legato. The test
- "Notes joined by a tie are each played." The note sounds once (values added). Re-striking is a clear error.
- "Slurs are only for instruments." In vocal music a slur means one syllable over several notes, one of its
- "A long arc must be a slur." Length is not the test. Pitch is — equal pitches make a tie however long it
is the pitch at each end.
commonest uses.
is. :::
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 连音线（tie）合并同音高的两个音符为一个音；圆滑线（slur）表示不同音高间的连奏，为记谱法通则
- 圆滑线在声乐中表示一字多音，为通行记谱规范
Used for fact-checking only; all prose is original.