Mic Array Output while silent

Hey guys,
if i run a demo for the mic array on a Maix Bit random LEDs blinks if it is silent. While playing an audio the mic array works fine. Is that normal? If no, is there a way to fix that problem?

Demo:
from Maix import MIC_ARRAY as mic
import lcd

lcd.init()
mic.init()

while True:
imga = mic.get_map()
b = mic.get_dir(imga)
a = mic.set_led(b,(0,0,255))
imgb = imga.resize(160,160)
imgc = imgb.to_rainbow(1)
a = lcd.display(imgc)
mic.deinit()

Mic Array connected:
GND = GND
VIN = 5V
MIC_BCK = Pin18
MIC_WS = Pin19
MIC_DAT3 = Pin20
MIC_DAT2 = Pin21
MIC_DAT1 = Pin22
MIC_DAT0 = Pin23
MIC_LED_DAT = Pin24
MIC_LED_CLK = Pin25