USB-C to jack DAC for iMM6

[Jean-Baptiste ROMANET]

Hi,

I have purchased an iMM6 mic and tested it on my Google Pixel 5 through a U-Green USB-C to headphone adapter, 10 EUR : https://www.amazon.fr/UGREEN-Adaptateur-Tress%C3%A9-Huawei-OnePlus/dp/B07MCT2684/ref=asc_df_B07MCT2684 

Using it, the measurement chain is limited by the background of the DAQ. I can not recognize the typical spectrum of the microphone electric background noise : After calibrating with a 94 dB calibrator there is a noise at 1 kHz.

A background noise is near 43 dBA.

Z background noise is 72 dB because of a huge level at 23 Hz (in FFT mode).

The nice thing is that high levels are supported : the signal is not overloaded at 114 dB.

Do you know a cheap USB-C to headphone adapter (or DAQ) giving a nice dynamic range with low background noise ?

(I will do electric tests on the 10 EUR UGreen DAQ I have to check its dynamic capabilities.)

By the way, if connected to a Samsung A71 phone, there is something changing the frequency response, like a low cut filter, and applying a gain. The high levels above 100 dBA are overloading the input but the background noise is ok down to 36 dBA.

[Jean-Baptiste ROMANET]

Self noise of the DAC when input in short-circuit :

In addition ton the 1 Khz and harmonics, there is a high level at 22  Hz :

Now A weighted :

I tried the same in flight mode, without improvement.

I should now try this USB-C DAC on Windows with RMAA or ARTA...