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The tanggu is the first membranophone on this site. Every instrument before it vibrated a string, a column of air or a metal body — from here on, what vibrates is a stretched surface: skin.

⚠️ For the first time pitch no longer comes from "length". | | What you change | The geometry that sets the pitch | |---|---|---| | Guqin · pipa | the stopped string | string length | | Dizi | open a hole | air-column length | | Xun | open a hole | cavity volume ÷ open area | | Bianzhong | nothing | bell shape (fixed at casting) | | Tanggu | skin tension · head diameter | the tension and size of a stretched surface | A drum's "length" is its diameter — a bigger head sounds lower, the same logic as "a longer string sounds lower". The difference is that skin tension can be adjusted afterwards (tuning) while diameter is settled when the drum is made. So the list of "what the player can control" gains another entry: strings by stopping · pipes by opening · bells not at all · drums by dividing the work between the maker and the tuner.

Structure: a double-headed drum on its side

Three points:

1. What vibrates is skin, not string or air. This is the site's first membranophone — and the skin is stretched over an enclosed air cavity, so a drum's sound is really skin and trapped air together. 2. Both heads can be struck. The skins face sideways and the body lies on its side — unlike the timpani or a Western bass drum; this is the practical form of a drum in a luogu ensemble. 3. Three knobs for "pitch": head diameter (set at making) · skin tension (tunable) · striking position (chosen in the moment). Centre and rim are different sounds — that is what "pitch" has been broken into here.

Drum patterns: information squeezed into time and colour

This figure connects the drum to the "signal" thread (see the bugle):

The drum deletes the pitch dimension entirely — and still directs a full band. The reason: information never needed pitch — it needs distinguishable patterns. The bugle supplies the difference by pitch; the drum by timbre. Both use the same underlying dimension: time.

Which is also why the most important person in an opera band is the drummer (司鼓): his patterns are not accompaniment but instructions — when to enter, when to close, when to change metre, when to speed up. Here an "instrument" is also the conductor.

Timbre, and how to hear it

Four cues:

1. A low boom. A large head gives a solid bottom, the foundation of a luogu ensemble. 2. "Dong" at the centre, "da" at the rim. On one drum, a different striking point is a different sound — so a drummer really has several "notes". 3. The short, dry damped stroke. Pressing a hand on the head and striking gives a clipped sound — the usual way to punctuate a pattern. 4. Decay is under the player's control. Let it ring, or stop it with the hand — the drum's tail belongs to the player, the opposite of the gong, whose ring is hard to stop.

Playing techniques

• Single strokes and rolls. Two beaters alternating produce a roll — the main way tension is built in luogu music.
• Damping and stopping. A hand or beater on the head controls the tail, and therefore the punctuation.
• Centre, rim, or the body itself: three striking points, three colours.
• It is the conductor. In opera the drummer (司鼓) directs the whole band with patterns — so a drummer must know both the drama and the music.
• Tuning is preparation, not performance. Skin tension can be set beforehand, but fingers cannot change the pitch while playing — unlike the timpani with its pedal.

The family

Within one struck family there are two forks: ① is the pitch definite (bells, timpani vs tanggu, gong); ② can it be changed live (timpani yes, bells no). The tanggu chooses to have no pitch at all — and that is exactly what frees it for another job: conducting.

History

The thing to remember: the drum is one of the very few instruments that went from tool to instrument and never stopped being a tool. Armies signalled with it, opera directs with it, festivals build momentum with it — and all three use the same material: rhythmic patterns.

Common misconceptions

• "A drum has no pitch, so it is not really music." On the contrary: it builds phrases out of time and timbre, and it can direct a whole band — information never required pitch in the first place (see the comparison with the bugle).
• "A drum is a drum." They differ greatly: pitched drums (timpani) and unpitched ones (tanggu, drum kit) are two classes; single- vs double-headed and tunable-live vs not are two more divides.
• "A tanggu is a Western bass drum." Different mounting (on its side, both heads playable vs upright or suspended), different beaters, and a different role in the ensemble.
• "Drummers just keep time." In opera the drummer is the conductor — entries, metre changes and closes are all issued from the drum, so the drummer must know the whole drama.
• "Tighter skin means higher pitch, so a drum can be tuned to any note." You can change the sense of pitch, not produce a fixed degree — which is why it counts as unpitched.
• "Hide in the bayin is only a material label." It is only a material label — but the material decides the essential fact about this family: the sound comes from a stretched surface, not a string, not air, not metal.

Next

The hide category is complete (the tanggu). Three bayin categories remain: wood · gourd · stone — and the next instrument turns to wood: the muyu. It is an unusual percussion instrument: no skin, no cavity, no pitch — just a block of wood with a long slot cut in it. Its question is: how simple can an instrument be and still be an instrument? :::

Sources

• 形制依通行乐器资料：木制鼓身，两端蒙皮（多为牛皮），横放，用两根木槌敲击；鼓面直径从二十余厘米到一米以上不等
• 「堂鼓属膜鸣乐器」依 Hornbostel–Sachs 分类 —— 振动体是绷紧的皮膜，这是本站第一件膜鸣乐器
• 「鼓面无固定音高」依通行乐器资料 —— 鼓面直径 · 皮的张力 · 敲击位置都会改变音高感，但不构成确定的音级
• 「鼓面越大，音越低；敲击鼓心与鼓边音色不同」依声学通识
• 「戏曲乐队中由鼓师（司鼓）用鼓点指挥全场；锣鼓乐中鼓是最主要的节奏组织者」依戏曲与民间器乐通行资料
• 「堂鼓属于八音中的革（兽皮）」依通行资料

Used for fact-checking only; all prose is original.