MATRIX Creator MEMS recordings are shorter than whole track

Hello dear community,

I hope – you can help me. I have a task to record different sources with MATRIX Creator MEMs Array. Recording works like in example fine. I’m using MATRIX Creator with Raspberry Pi 4bThe Problem is that my audio File have a right length
(ex. if I’m starting ./record -duration 320 I get a 9 audio files with a length of 320 sec) but the recording goes longer ~400sek. So, a software/hardware records 400sec and shrink it to 320. See example on screenshot (above is original track with 320 sec, below are recordings from MATRIX MEMs Array – length difference is about 48 sec)!

What is the problem, what can I do? I do already all updates/upgrades and setting out to use different sampling frequencies.

I greatly appreciate your help in advice
greetings
Nik

Additionally, to further topic – the Problem is allocated:

We are talking about many packet losses of the data. As it looks, some data is “swallowed”. At sampling rate of 44100 Hz it happens (partially) in regular intervals (visible peaks with the interval of 1sec and missing parts of the wave).

On the other hand, at a smaller sampling rate, e.g., 16kHz, no comparable peaks can be found. Nevertheless, the recordings are not of the same length as the source. So, decreasing the sampling rate brings some improvement (recording is steadier), but does not solve the problem completely. The positive thing is that the packet loss happens synchronously (with all 8 microphones/channels at the same time), so e.g., the direction finding is still possible.

On the screenshots, you can see the following waveform and spectrogram of the audio files:

at 44100Hz:

  1. Generated test signal 120 sec long with 5 sec start and stop 1 kHz sine signal and a 30 sec 500 Hz sine signal in the middle.
  2. A1_1 recording with MEMs array, 120 sec, 5 channel
  3. A1_2 recording with MEMs array, 120 sec, 5 channel (same conditions as before)
  4. recording with MEMs array, 180 sec, 5 channels

at 16000 Hz:

  1. Generated test signal for 120 sec with 5 sec start and stop 1 kHz sine signal and a 30 sec 500 Hz sine signal in the middle.
  2. recording with MEMs array, 120 sec, 5 channel
  3. recording with MEMs array, 120 sec, 5 channel (same conditions as before)





If someone knows a solution of the problem—please let me know!
Sincerely yours
Nik


Two last screenshots