The changgo is the most representative drum in traditional Korean music. It is available in most kinds, and consists of an hourglass-shaped body with two heads made from animal skin. The two heads produce sounds of different pitch and timbre which when played together are believed to represent the harmony of man and woman.

The instrument was originated from Korea in 57bc to 935ad in Goryeo.

It is made from a hollow, hourglass-shaped wooden body of either porcelain, tile, metal, wood, gourd, or tinned sheet. 

Jorongmok is the round tube in the middle connecting the left and right side of the hourglass-shaped body. The size of the jorongmok determines the quality of the tone: the wider the tube, the deeper and huskier it sounds; the narrower the tube, the harder and snappier it sound

Both sides are made of animal skins.

There are two kinds of beating sticks, namely gungchae and yeolchae. The gungchae is shaped like a mallet with a round head. The handle is made from bamboo root, boiled and straightened out and the head is made from hardwood such as birch or antler. Modern gungchae may also be made from plastic; this variety is normally used by beginning musicians. The yeolchae is always made from bamboo. The yeolchae has a thin body with a handle thick handle made of bamboo

 

 

To play, both sides are to be hit to produce a melody. The changgo is used in folk songs.

Some interesting facts of the changgo

-The changgo or sometimes called seyogo. The two heads produce sounds of different pitch and timbre, which when played together are believed to represent the harmony of man and woman.

-The skins are lapped on to metal hoops to scure the surface. The left side produces deep and low tones.

-The right side produce higher tones.

The Yangqin was introduced to south coastal China in the 17th century after trading with the middle east. 

The Yangqin is made out of strings, bridges, hammers and cylindrical nuts. There are usually 144 strings in a modern Yangqin, the strings come in different thickness, which are then tied up by the screws. They are usually covered up by a panel, which is only opened if the Yangqin requires tuning. The hammers are used for playing the Yangqin, and they are made of flexible bamboo at one end while the other end is covered with rubber. The bridges are attached with the strings and there are usually 4 to 5 bridges in a Yangqin. The cylindrical nuts are the metal screws at the side which can be moved when the instrument is needed to tune.

The Yangqin is commonly used during Chinese Chambers and orchestral ensembles.

As for the manner of performance, the sticks are held, one in each hand, and hit the strings alternately. In the orchestra, the yangqin often adds to the harmony by playing chords or arpeggios. Since yangqin is softer than other Chinese instruments, therefore it is usually positioned at the front of the orchestra, in the row just in front of the conductor. However, this is not a rule; as the Singapore Chinese Orchestra positions the yangqin close to the percussion section. Because the yangqin's tones will sustain long after they have been played, such an arrangement minimises the dissonance that results. If the hands are free, like during the periods when they are not playing, covering the strings with the hands quickly dampens the vibrations. The yangqin has been called the "Chinese piano" as it has an indispensable role in the accompaniment of Chinese string and wind instruments.

The yangqin's solo repertoire calls for more techniques than is usually required in orchestral pieces. Examples include pressing down on the strings to produce vibrato effects, similar to that of a guzheng, as well as harmonics and 顫竹 (chàn zhǔ), which involves flicking the sticks lightly over the strings, causing them to vibrate, which results in a short, quick tremolo. Many other techniques, such as portamento - a glide from one note to another, which can be accomplished through 2 methods, both involving the lengthening or shortening of strings: the first is by sliding the fine-tuning devices on the sides of the instrument by hand, and the second is by wearing a metallic "ring".

Below is a video link that shows a demonstration on how to play a yangqin. 

The Balafon produces distinctive sounds and has a traditional style, thus has been exported to western instruments. Its keys are traditionally made from a special type of wood. It is the dried slowly over a low flame, and finally it is then tuned by shaving off bits of wood from the underside of the keys. Wood is taken off in the middle so as to flatten the key, or is taken off in the end to sharpen it. It usually has 17-21 keys, tuned to 3 different types of scales, a tetratonic, pentatonic or heptatonic, depending on the culture of the musician.

In a fixed-key balafon, its keys are suspended by leather straps above the wooden frame, under which are hung graduated-size calabash gourd resonators. A small hole in each gourd is covered with a membrane. The membrane is traditionally made of thin spider’s-egg sac filaments, but nowadays more usually made of cigarette paper or thin plastic film as they are more convenient. The Balafon is played with two gum-rubber-wound mallets while seated on a low stool, or while standing using your shoulder or waist sling hooked to its frame.

The Balafon can be played alone in a ritual context, in others as part of an ensemble. In Guinea and Mali, the Balafon is often played as part of an ensemble of three people, pitched as low, medium and high. In Cameroon, on the Gulf of Guinea, six Balafon of varying size perform together in an orchestra, called a komenchang.
Here is a picture of a Barafon:

It originates from Kaya Kingdom ( mid-1st century to mid-6th century).