审阅范围 · Review scope
限定范围独立审阅。请保留正文中的出处与限制；不代表全库最终验收、实际演奏或学习效果验证。
Independent review within the stated scope. Keep the evidence and limitations stated in the text in view. This is not final corpus acceptance or validation of performance or learning outcomes.
本页保留作者送审冻结字节，因此正文或数据可能仍有“候选／等待审阅／未发布”标记。当前版本已通过限定独立复核并发布；旧标记只记录冻结时状态。通过范围是双语含义、限定来源文字／静帧及原创固定例题检查，不含原声听校、连续动作、完整源谱、实际演奏、身体适用性或学习效果验证。
This page preserves the author’s frozen review bytes, so prose or data may still contain candidate, pending-review or unpublished labels. This version has passed bounded independent review and repository publication; those labels record author-time status only. Acceptance covers bilingual meaning, bounded source text/stills and original fixed-fixture checks, not source audition, continuous motion, full source scores, actual performance, physical suitability or learning outcomes.
持续低音：分清音高、起音与踏板
低音没换，为什么还可能重新起音？
一段音乐先写Eb和弦，再写Ab/Eb，最后回Eb。三处低音都指定Eb，就表示低音只弹一次吗？不一定。本课把“低音是什么”“什么时候重新起音”和“是否踩右踏板”分开，用三份完整时间表核对。
先能读字母音名、四分单位与三和弦即可。b是降号；Eb与E♭同义。C4是中央C，数字是八度而非指法。若需要，先看文末的音程与六四前置笔记。本页以纸笔为主，钢琴是可选路线；四条声部表示四条同时的音线，不表示四只手。
先遮住答案，写下预测：如果Eb3在0到6之间不断音，中间还能形成Ab/Eb吗？若在2与3处重新弹同一个Eb3，和弦根音会改变吗？如果只给Ab/Eb这个名字，能决定踏板和起音吗？“待定”也是可以记录的答案。
三个不同层面的名称
本课的持续低音（bass pedal／pedal point）指一段连接中保持或重复的低音参照。它描述音线；本课H连续保持Eb3，R在相同音高重新起音，两者都保留Eb低音。这里没有把所有持续低音限定为必须不协和：它可能是当前和弦音，也可能在另一些和声中成为和弦外音。
右踏板（damper pedal）是钢琴控制装置；它与持续低音的分析名称不是一回事。持续低音可以由按住或重弹琴键形成，也可写给其他乐器。斜线和弦、六四数字及“pedal”分析标签本身都不给踩踏时间。本页可选钢琴路线明确不用右踏板，免得把低音线与整体延响混在一起。
Eb大三和弦由Eb–G–Bb构成；Ab大三和弦由Ab–C–Eb构成。根音是和弦的命名参照，低音是此刻实际最低的音。Ab/Eb表示Ab和弦以其五音Eb作低音，因此是第二转位；根音仍是Ab。在Eb大调这个给定语境里，三个和弦可标I–IV6/4–I。
把Ab/Eb紧凑地写成Eb3–Ab3–C4，从Eb按字母数到Ab是四度、到C是六度，分别为5和9半音。“六四”来自低音上方的这些音程，既不是6/4拍号，也不是六个音加四个音。本页实际配置把Ab移到Ab4；复音程缩到同类单音程后仍是四度，转位不变。
“持续低音六四”还需要前后连接。在本例，Eb3保持，Bb3–C4–Bb3与G4–Ab4–G4两条上声部离开后返回，Eb4保持。这支持把中间Ab/Eb读作主和弦上的邻接装饰；也常称邻接六四或辅助六四。孤立的Ab/Eb只决定三和弦与转位，不能单独保证这种作用。
三版共用的完整时间框架
所有版本均为原创两小节4/4。q是四分音符单位；全局q从0开始，小节开头在0与4，段末在8。四分音符＝60 BPM时整段8秒，其中0到6有写出的音，6到8所有声部休止。声部同时进行，不能把四条8q相加成32q的演奏长度。
事件写作音名[a,b)，表示a处起音、b处结束，不包含b；它不是新的拍号。表中每行已列出全部音符与末尾休止，没有隐藏伴奏。一个事件跨小节时保持到其终点；q=4没有任一声部重新起音。若改写成传统谱面，需要把同声部、同音高的跨小节片段用延音线连接。
H是保持低音版，R是重复低音版；两版上方三条音线完全相同。M保留R的起音时刻和所有上声部，只将中间低音Eb3换成Ab3，成为移动低音对照。三版分开读或演奏，不能叠在一起。
这些终点是记谱与练习意图，没有测量琴键释放或声音消失。钢琴持续音会衰减；休止也不保证绝对声学静音。不要为了每拍都出现新声音而偷偷重弹H的低音；若选择R，应把新起音作为有意改变而记录。
H: 保持低音; R: 重复低音; M: 移动低音对照
完整事件表
| 版本 | 声部 | 全部音符事件 | 休止 |
|---|---|---|---|
| H | 低音 | Eb3[0,6) | [6,8) |
| H | 下内声部 | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| H | 共同音声部 | Eb4[0,6) | [6,8) |
| H | 最高声部 | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
| R | 低音 | Eb3[0,2); Eb3[2,3); Eb3[3,6) | [6,8) |
| R | 下内声部 | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| R | 共同音声部 | Eb4[0,6) | [6,8) |
| R | 最高声部 | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
| M | 低音 | Eb3[0,2); Ab3[2,3); Eb3[3,6) | [6,8) |
| M | 下内声部 | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| M | 共同音声部 | Eb4[0,6) | [6,8) |
| M | 最高声部 | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
核对音线、和弦和起音
H与R在[0,2)、[2,3)、[3,6)的实际音高集合相同。中间四音是Eb3–C4–Eb4–Ab4，属于Ab三和弦而以Eb最低；重复Eb只是重复五音，不增加新的和弦种类。上声部Bb3到C4上行2半音，G4到Ab4上行1半音，然后分别原路返回。
H低音只有1次起音；R低音有3次，分别在0、2、3。包括所有声部，H共8次音符起音，R共10次；两版出现新音的不同时点仍同为0、2、3。q=2时H只有两条移动上声部新起音，R则多一个低音起音，共3次；Eb4在两版都不重起。
M中间实际音为Ab3–C4–Eb4–Ab4，最低Ab就是根音，因此写Ab原位，不写Ab/Eb。M低音Eb3–Ab3–Eb3先上行5半音，再下行5半音；它已失去本例持续Eb低音。M与R同为10次起音，可见起音次数相同不保证低音路线相同。
“保持低音”不等于“上声部不动”，也不等于“每个音都必须相连”。贯穿整个[0,6)的保持音只有H的Eb3和三版共用的Eb4；其他音按表改变。R的相邻同音事件在边界重起，并未用延音线合并；它们没有额外的谱写休止，但实际发音间隙仍须在演奏时观察。
核对结果
| 版本 | 和弦连接 | 低音起音q | 总音符起音 | q=2新起音 |
|---|---|---|---|---|
| H | Eb → Ab/Eb → Eb | 0 | 8 | 2 |
| R | Eb → Ab/Eb → Eb | 0,2,3 | 10 | 3 |
| M | Eb → Ab → Eb | 0,2,3 | 10 | 3 |
音区与88键核对
| 音名 | MIDI | 88键序号（A0=1） |
|---|---|---|
| Eb3 | 51 | 31 |
| Ab3 | 56 | 36 |
| Bb3 | 58 | 38 |
| C4 | 60 | 40 |
| Eb4 | 63 | 43 |
| G4 | 67 | 47 |
| Ab4 | 68 | 48 |
先做纸面任务，再选择是否弹奏
纸面任务1：用两种颜色标出H与R每个起音，以及仍在保持的音。先按声部数，再按时点数。在q=2处写出全部四个在响的记谱音，同时把“正在响”与“刚开始”分两列。答案是四个音仍占时值，但新起音分别为2与3。
纸面任务2：把M中间低音错误写成Ab2，是否仍为原位Ab？是；但它不再是本题指定音区与5半音上行路线。把H中间根音误填Eb则应纠正：从Ab–C–Eb辨认根Ab，再核最低音Eb。一个答案可在转位层面正确而在本题音区层面错误。
可选钢琴路线：不用右踏板，先单独弹低音或只弹最高声部，按完整0到8的时间走，并保留末尾休止；每次只选一条线。这是局部练习，不是四声部已完成。能从容协调时再把低音交左手、上方三音交右手，仍以慢而均匀的四分脉冲读完整表。60 BPM只用于算术，若换速度要重新记录；不规定统一指法。
若只练中间[2,3)，H的Eb3与Eb4已从0进入，不能从静止按出一个和弦就说保留了原起音计划。要保留原事件，加前导从0开始；或明确把孤立和弦标成新练习。修完一个问题后，恢复本来选择的H、R或M完整两小节，连同三条上声部、原起音与6到8休止。
稍后或次日，先遮住答案，不先重复热身，重写熟悉版本H与R的低音事件，再读完整两小节并核q=2与q=4。记录日期、纸面或钢琴、版本、实际速度、错在哪一条线、修正后结果及延迟。重新做相同材料才是这里的保留重测；换调或换节奏属于另一项迁移任务，不能混成同一个分数。
记录单的初始值全部为未知，不能把本页答案当成自己的完成记录。纸面核对可证明这次写出的音名与时值是否符合题设；可选弹奏记录还要分开写实际观察。单次成功或主观稳定感不证明长期学习效果，也没有对原视频听感作验收。
待填写的记录
| 项目 | 初始值 |
|---|---|
| 日期、版本、路线、实际速度 | 未知 |
| 预测及纸面纠错 | 未知 |
| 完整两小节恢复结果 | 未知 |
| 实际弹奏观察（可选） | 未知 |
| 延迟及熟悉材料保留重测 | 未知 |
适用范围：不要只凭低音相同就贴标签
在常见调性练习中，I–IV6/4–I是持续低音六四的一种典型模型；本例用于解释邻接上声部与主音低音的关系，不是所有古典作品唯一合法写法。音乐风格、拍位、时长、旋律、前后目标与分析体系都会影响功能判断。其他六四用法见前置笔记，不因低音暂时保持就全部归为本类。
两个静态拼写题不含节奏或弹奏要求：Ab/Eb的三和弦音是Ab–C–Eb，低音Eb是五音；Db/Eb的上方Db–F–Ab配Eb低音时，Eb不是Db三和弦成员，不能因此把它叫作Db第二转位。持续低音可以承载别的和声，但“持续低音”不自动保证每个切片都是三和弦六四。
小调可采用相似的邻接构想，但必须重核和弦音与半音距离，不能只把大调标签改成小写。现代编配也可探索别的和弦与低音，但是否保留六四结构、低音身份与所要的效果都需逐项判断。本页没有把“任何和弦都可以”升级为通用替换许可，也不保证H、R或M哪一版必然更好听。
来源只支持什么
NC-069既有机器转写87段已全部阅读；44、65、106、161、214秒共5张静帧已查看。44秒可见持续低音六四的标题与同低音说明；65与106秒可见C、F/C、C及C、F、C的对照标签；161秒可见Cm、Fm、Cm与Cm、Fm/C、Cm；214秒可见四个红框斜线和弦标签。这里只核可见文字与版面，不逐音接受整个源谱。
转写候选把相同低音、I–IV6/4–I和小调类比作为说明，并提出稳定或动态的听感比较及更广的现代用法。这些归属未经原声听校；静帧不能证明其听感。含模糊音名的段落不用于核定实际音高，广泛频率与任意替换的强主张也不作为本课规则。
本页Eb大调音区、三版声部、时间、起音核对、局部练习及保留记录均为本库原创，不复刻源曲。没有原声听校、连续动作、完整源谱、ASR与静帧精确对齐、身体适用性或学习效果验收。库存340.822秒与容器340.800秒相差0.022秒，原因未明；两者都不是本次实际听看时长。
这是等待独立审阅的候选稿，公开文件不含原图、原声、完整转写或私人路径。计算检查只验给定数据与文字镜像，不是一般音乐分析器；ASR文字加选定静帧的有限覆盖不能称为全视听审阅。
相关阅读
原始数据与记录
有限来源范围
固定例题检查
Bass pedals: separate pitch, attacks and foot pedals
Why can an unchanged bass still have a new attack?
A passage goes from Eb to Ab/Eb and back to Eb. If all three bass notes are specified as Eb, is the bass played only once? Not necessarily. This lesson separates bass identity, attack timing and damper-pedal use through three complete timelines.
Start with letter names, quarter-note units and triads. The b is a flat, so Eb and E♭ mean the same spelling. C4 is middle C; the number is an octave, not a fingering. Use the interval and six-four prerequisite links below if needed. Paper is the main route and piano is optional; four voices are simultaneous musical lines, not four hands.
Hide the answers and predict: can Ab/Eb occur while Eb3 lasts from 0 to 6? If the same Eb3 is reattacked at 2 and 3, does the chord root change? Can the name Ab/Eb alone decide pedal use and attacks? “Undetermined” is an acceptable recorded answer.
Names at three different levels
Here a bass pedal or pedal point is a bass reference held or repeated through a progression. It describes a line: H sustains Eb3 continuously and R reattacks the same pitch, preserving Eb as bass in both. A pedal is not required to be dissonant throughout: it may belong to a current chord and become a non-chord tone against other harmonies.
The damper pedal is a piano control, distinct from the analytical term bass pedal. A bass pedal can be formed by holding or repeating keys, or written for another instrument. Slash chords, six-four figures and an analytical “pedal” label do not themselves prescribe foot timing. The optional piano route here explicitly omits the damper pedal so the bass line and general resonance can be considered separately.
The Eb-major triad contains Eb–G–Bb, and the Ab-major triad contains Ab–C–Eb. The root names the chord; the bass is the actual lowest pitch at the moment. Ab/Eb puts Eb, the fifth of Ab, in the bass, so it is second inversion with root Ab. In the stipulated key of Eb major, the three chords can be labeled I–IV6/4–I.
Write Ab/Eb compactly as Eb3–Ab3–C4. Counting letters from Eb gives a fourth to Ab and a sixth to C, at 5 and 9 semitones respectively. “Six-four” refers to these intervals above the bass, not a 6/4 time signature or six notes plus four notes. Our actual voicing places Ab at Ab4; reducing that compound interval to its simple class still gives a fourth, with the same inversion.
A pedal six-four also needs surrounding context. Here Eb3 remains, the upper lines Bb3–C4–Bb3 and G4–Ab4–G4 depart and return, and Eb4 stays. This supports reading the middle Ab/Eb as a neighboring decoration of the tonic, also called a neighboring or auxiliary six-four. An isolated Ab/Eb establishes the triad and inversion but cannot by itself guarantee that role.
The complete shared time frame
All versions are original two-bar passages in 4/4. A q is a quarter-note unit; global q starts at 0, bars start at 0 and 4, and the passage ends at 8. At quarter note=60 BPM the passage lasts eight seconds, with written notes from 0 to 6 and rests in every voice from 6 to 8. Voices run together; four 8q lines do not make a 32q performance.
An event written pitch[a,b) attacks at a and ends at b, excluding b; this is not a new time signature. Each table row lists every note and the closing rest, with no hidden accompaniment. An event crossing a barline lasts to its endpoint; no voice reattacks at q=4. In conventional notation, same-pitch fragments of that event across the barline need a tie in the same voice.
H holds the bass and R repeats it; their three upper lines are identical. M preserves R’s attack times and all upper voices, changing only the middle bass from Eb3 to Ab3 as a moving-bass comparison. Read or play the versions separately, never superimposed.
These endpoints are notation and practice intentions, not measurements of key release or sound cessation. A piano tone decays, and a rest does not guarantee absolute acoustic silence. Do not secretly reattack H’s bass merely to produce a new sound every beat; when choosing R, record the new attacks as intentional changes.
H: Held bass; R: Repeated bass; M: Moving-bass comparison
Complete event table
| Version | Voice | All note events | Rest |
|---|---|---|---|
| H | Bass | Eb3[0,6) | [6,8) |
| H | Lower inner | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| H | Common-tone voice | Eb4[0,6) | [6,8) |
| H | Top | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
| R | Bass | Eb3[0,2); Eb3[2,3); Eb3[3,6) | [6,8) |
| R | Lower inner | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| R | Common-tone voice | Eb4[0,6) | [6,8) |
| R | Top | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
| M | Bass | Eb3[0,2); Ab3[2,3); Eb3[3,6) | [6,8) |
| M | Lower inner | Bb3[0,2); C4[2,3); Bb3[3,6) | [6,8) |
| M | Common-tone voice | Eb4[0,6) | [6,8) |
| M | Top | G4[0,2); Ab4[2,3); G4[3,6) | [6,8) |
Check lines, chords and attacks
H and R have the same actual pitch collections on [0,2), [2,3) and [3,6). Their middle four pitches are Eb3–C4–Eb4–Ab4, an Ab triad with Eb lowest; doubling Eb doubles the fifth without adding a chord type. Bb3 rises 2 semitones to C4 and G4 rises 1 semitone to Ab4, then each returns by the reverse path.
H has one bass attack; R has three, at 0,2,3. Across all voices H has eight note attacks and R ten, but the distinct times containing any new attack remain 0,2,3 in both. At q=2 only the two moving upper voices attack in H; R adds a bass attack, making three. Eb4 does not reattack in either.
M’s middle pitches are Ab3–C4–Eb4–Ab4. Lowest Ab is the root, so the chord is root-position Ab, not Ab/Eb. M’s bass Eb3–Ab3–Eb3 rises 5 semitones and falls 5, losing this example’s continuing Eb bass. Both M and R have ten attacks: equal attack counts do not guarantee the same bass path.
“Hold the bass” does not mean “freeze the upper voices” or “connect every note.” The tones sustained continuously through all of [0,6) are H’s Eb3 and the Eb4 common to all three versions; other tones change as listed. R’s adjacent same-pitch events reattack at their boundary and are not merged by a tie. They contain no added written rest, while any actual gap in sound still requires performance observation.
Check results
| Version | Chord sequence | Bass attack q | Total note attacks | New attacks at q=2 |
|---|---|---|---|---|
| H | Eb → Ab/Eb → Eb | 0 | 8 | 2 |
| R | Eb → Ab/Eb → Eb | 0,2,3 | 10 | 3 |
| M | Eb → Ab → Eb | 0,2,3 | 10 | 3 |
Registers and 88-key check
| Pitch | MIDI | 88-key number (A0=1) |
|---|---|---|
| Eb3 | 51 | 31 |
| Ab3 | 56 | 36 |
| Bb3 | 58 | 38 |
| C4 | 60 | 40 |
| Eb4 | 63 | 43 |
| G4 | 67 | 47 |
| Ab4 | 68 | 48 |
Paper first, then optional piano
Paper task 1: use two colors to mark each attack in H and R and the notes that continue. Count by voice first, then by distinct time. At q=2 list all four notated sounding pitches, using separate columns for “occupying time” and “just starting.” Four tones occupy time, but there are respectively two and three new attacks.
Paper task 2: if M’s middle bass is mistakenly written Ab2, is the chord still root-position Ab? Yes, but it no longer has this task’s register or 5-semitone rising path. If H’s middle root is mislabeled Eb, correct it by identifying root Ab from Ab–C–Eb and then checking bass Eb. An answer can be correct about inversion while wrong about the specified register.
Optional piano route: omit the damper pedal and first play only the bass or only the top voice through the full 0-to-8 timeline, retaining the closing rest; choose one line per attempt. This is partial practice, not completion of all four voices. When coordination is comfortable, assign bass to the left hand and the three upper notes to the right and read the whole table with a slow, even quarter pulse. The 60 BPM value is for arithmetic; record any chosen tempo change. No universal fingering is prescribed.
If you isolate [2,3), H’s Eb3 and Eb4 carry in from 0. Starting a chord from silence cannot count as preserving the original attack plan. To retain the events, include the lead-in from 0, or explicitly label the isolated chord a new exercise. After fixing one issue, restore the chosen H, R or M as a complete two-bar passage, with all three upper voices, original attacks and the rest from 6 to 8.
Later or the next day, hide the answers and, before rehearsing them again, rewrite the familiar H and R bass events, then read the complete two bars and check q=2 and q=4. Record date, paper or piano route, version, actual tempo, the line containing an error, the result after correction and the delay. Repeating the same material is the retention retest here; changing key or rhythm is a separate transfer task and should not be merged into one score.
The record starts entirely unknown; the answer key is not your completion record. Paper checking can establish whether the written pitches and durations match this task on that attempt; optional playing needs separately recorded observations. One successful attempt or a subjective impression of stability establishes neither long-term learning effects nor acceptance of the source video’s sound.
Record to complete
| Item | Initial value |
|---|---|
| Date, version, route, actual tempo | unknown |
| Prediction and paper correction | unknown |
| Complete two-bar restoration result | unknown |
| Actual playing observation (optional) | unknown |
| Delay and familiar-material retention retest | unknown |
Limits: a shared bass is not enough to assign the label
In familiar tonal exercises, I–IV6/4–I is a typical pedal-six-four model. Our example explains neighboring upper voices over a tonic bass, not the only permitted pattern in all classical music. Style, metrical position, duration, melody, surrounding goals and analytical convention affect function. See the prerequisite note for other six-four uses; a temporarily stationary bass does not place them all in this category.
Two static spelling questions, with no rhythm or playing instruction: Ab/Eb contains triad tones Ab–C–Eb and bass Eb is its fifth; placing Db–F–Ab above an Eb bass in Db/Eb makes Eb a nonmember of the Db triad, so this is not Db in second inversion. A pedal can support other harmonies, but “bass pedal” does not guarantee every slice is a triadic six-four.
A similar neighboring idea can be used in minor, but chord tones and semitone distances must be checked again rather than merely changing Roman-numeral case. Modern arranging may explore other harmonies and basses, but six-four structure, bass identity and the intended effect each need checking. This page does not elevate “any chord works” into a universal substitution license or guarantee which of H, R or M sounds better.
What the source evidence supports
All 87 segments of the existing NC-069 machine transcript were read, and five stills at 44,65,106,161,214 seconds were inspected. At 44 a pedal-six-four title and shared-bass description are visible; 65 and 106 show labels comparing C–F/C–C with C–F–C; 161 shows Cm–Fm–Cm and Cm–Fm/C–Cm; 214 shows four red-boxed slash-chord labels. This checks visible text and layout, not every note of the complete source score.
Transcript candidates explain a shared bass, I–IV6/4–I and a minor analogy, and propose stable-versus-dynamic impressions and broader modern uses. These attributions have not been checked against the original audio; stills cannot establish the impressions. Ambiguous note-name passages do not determine actual pitches, and broad frequency or unrestricted-substitution claims are not lesson rules.
The Eb-major registers, three versions, timelines, attack checks, partial practice and retention record are original to this repository, not reconstructions of source music. There was no source-audio audition, continuous-motion review, complete source-score audit, exact ASR-to-still alignment, physical-suitability assessment or learning-effect acceptance. Inventory duration 340.822 seconds and container duration 340.800 seconds differ by 0.022 seconds for an unexplained reason; neither is the time actually listened to or watched in this review.
This candidate awaits independent review; its public files contain no source images, source audio, complete transcript or private paths. Calculation checks cover stipulated data and text mirrors, not a general music analyzer. Limited coverage of ASR text and selected stills is not full audiovisual review.
Related reading
Six-four structure and context
Structured data and record
Limited source scope
Fixed-fixture checks