Usually, the presentation of ca trù is done by a group of artists consisting of a đào (always a female singer) playing while singing her castanets, an artist called kép (the partner always a man accompanying the singer with his lute) and a third person playing the small drum called a quan viên (literally “distinguished guest” who in ancient time was usually the author of the new lyrics and also a fine connoisseur of this art).
Below are some knowledge related to the musical instruments needed for the understanding of the presentation of ca trù.

a.  The phách (or “castanets”)  
Phách is a kind of percussion instrument guiding the musical rhythm and also serving the dancers.

The Phách using in the presentation of ca trù is made of three parts, the support or bàn phách, the stick or tay ba, and two slats or lá phách.
The support is made of a piece of old “virile” bamboo (the opposite of the bamboo “female” with empty trunk) with the average length of 30cm and the average width of 4cm, the two knots was preserved to raise the same support.
The stick ( tay ba ) practically made up a “double stick” serving to beat on the support.
The two slats length is the same as of the stick is held by the left hand of the singer during the performance. The sound produced by the stick  is dull, soft and a bit “blurred” while the sound produced by the two slats is pure, brittle and clear. The lá phách and the stick-tay ba were made of the trắc wood, from the family of “steel-wood”.
Although simple in its structure, the techniques of use of the phách were very rich, the main ones as follows:
-    The technique known as hasty or the ngón rục: the stick-tay ba knocks one time on the support followed with two sounds made on the lá phách or vice versa. These three hasty sounds made the ngón rục.
-    The technique known as husky or the ngón chát: the stick-tay ba and the two slats knock together on the support to produce hoarse sounds.
-    The technique known as tremolo or the ngón vê: the stick-tay ba and the slats successively produce double sounds on the support at each  rhythm.

b. The đàn đáy
Normally, the resonance of every string musical instrument is necessarily made from a harmonic box, and every box of this kind necessarily has a bottom. And yet, this bottom, the đàn đáy has not! The name which originally means the lute with a bottomless box, has got its abbreviated form which later on became literally “lute-bottom”.

The lute named as  đàn đáy has four main parts:
-    The wooden and trapezoid harmonic box. The great trapezoid basis with its average width of 23–30cm is in the upper part of the box, while the small trapezoid basis with its average width of 23–30cm is in the lower part of the box. The average thickness of the two sides of the trapeze is about 31–40cm. The borders of this box are made of hard wood with its thickness of about 8–10cm. The surface of the box is made of ngô đồng wood and equipped with string hooks.
-    The stalk length is from 1.10 to 1.40 cm with 10 to 12 bamboo “ramps” (16 for the ancient đàn đáy). These “ramps” are thick and high, the part that put down on the stalk is longer than the opposite part. Curiously, the first “ramp” is on the middle of the stalk, not in the upper end of the stalk.
-    The upper end of the stalk has the form of a banian leave with three axes for the string tuning.
-    There are  three strings made of silk threads, which are long and soft, easy for fingering, each string has its own name, the dây hàng, dây trung and the dây tiếu going from the most thick to the most thin. Nowadays, these strings are made of polyvinil with different shape according to the four levels of the diatonic scale. Each string played five tone scales with five names known as cung Nam, cung Bắc, cung Nao, cung Huỳnh and cung Pha, the equivalant to Do, Re, Fa, Sol and La of the music theory .
The sound of the đàn đáy possess an acoustic measure greater than two octaves, with its low, troubled timber, having the ability to translate the most profound feelings.
In ancient times, the đàn đáy player usually made use of a plectrum made of a bamboo trifle, and nowadays the same plectrum is made of plastic.
The techniques of playing đàn đáy for the right hand are consisting of the pluck up, the pluck down, and the tremolo, similar to the playing of the pi po and the moon lute. For the left hand, the fingering techniques of đàn đáy are made up of profound sounds, pressed sounds, superimposed sounds and tune matched sounds (in Vietnamese, the ngón chìm, nhấn, chồng âm and the hợp âm).

c. The trống chầu (small drum)

The two circle faces of the small drum have each about 15cm diameter. Normally, the face of the small drum is made of grated buffalo skin taken from its armpit, thus giving it a long lasting usage. The skin which covers the face of the small drum has about a 3cm border  linking to the body of the drum due to small bamboo nails. The tight drum skin must also well matched with the voice of the singer. The height of the drum sound box is about 18cm and made of jack-fruit monolithic wood (called in Vietnamese tang liền), but sometimes this box could be done from separate small pieces of wood, the whole linking together with lacquerware. The two 2.5cm long drum sticks are made of soft wood, the holding part more thick than the other.
The timbre of the drum is neat, and during the presentation, the sound of the drum will have its specific tune according to the feelings thence the expression of the player, would it be satisfaction or blame.