Room acoustic treatment

Premise:

I need good acoustics to record the voice, I’m not interested in using the room for mixing or mastering.

Room size:
Height: 265 cm
Length: 530 cm
Width: 360 cm

Ceiling feature:

The false ceiling is formed by a metal structure lowered by 20 cm. On the metal structure, 60×60 cm polyurethane panels have been mounted with a density of 40 kg (the panels are covered with a thin white felt fabric). Internally there is 8 cm mineral wool with a density of 20 kg, finally an airgap of 7 cm remains.

Size of the false ceiling: width 360 cm, length 530 cm

Feature of the wall behind the studio monitors:

The wall has a 6 mm pine plywood surface that weighs 2.5 kg per square meter. Pine wood is 7 cm apart from the original concrete wall and is filled internally with 5 cm rock wool that has a density of 50 kg.

Wall size: Height 265 cm, Width 360 cm.

Purpose of this wall: I built this wall as a membrane, with the aim of absorbing the low frequencies from 120 to 180 hz.

Characteristic of the left wall (where there is the TV):

The wall has a 6mm pine wood surface (mass 2.5kg m2) and is 20cm apart from the original concrete wall. Inside the wooden wall there is a layer of 5 cm rock wool (50 kg) and a second 15 cm layer of mineral wool with a density of 20 kg.

Wall size: height 265 cm, length 530 cm.

Purpose of this wall: I built this wall as a membrane, with the aim of absorbing the low frequencies around 90 to 200 hz.

Characteristic of the right wall (where the sofa is):

The right wall is covered with a trevira cs fabric (100% POLYESTER) with 5 cm of 50 kg rockwool inside and 13 cm of mineral wool (20 kg), 13 cm thick. This false wall was built in front of the plasterboard which is 5 cm away from the original concrete wall.
Wall size: height 265 cm, length 530 cm

Characteristics of the wall opposite the studio monitors (where there is a window):

This wall is made of concrete and has a width of 360 cm and a height of 265 cm.

Room acoustic measurements:

The measurements were made in front of the listening point (I can record the voice in the area around the listening point to simplify everything.), I state that I am interested in using this room only to record the voice.