Hello,
I have a iMX6DL 512MB V1.1Y on Colibri Evaluation Board rev3.2 running wince 7. I use MAX4466 Electret Microphone Amplifier on LINE IN and record it. I save the recordings and hear them on the computer. While I increase the gain on max4466 the recording volume seems the same while the voice gets distorted because of the increased gain. I guess the LINE IN drops the volume to a MAX cap. Is there a way to increase the input volume of the LINE IN?
Hello @tasosgym,
The module is using the NXP SGTL5000 codec.
In table 4 you can see the max line in levels.
So you might overdrive the Amp or the input of the sgtl5000
Why are you not using the MIC input of the module?
Best Regards,
Matthias Gohlke
We are still working on it. We are trying with MIC input right now but it’s not exactly what we want. We might get back to LINE IN in the future. Thank you for the replies!
I must admit that I am not familiar with the MAX4466 myself. However, based on the information from the MAX4466 datasheet, it appears to have a fixed gain. To gat a better understanding of how to control its gain, could you kindly provide me with more details or instructions on the specific method or setup you are using for gain control?
The MAX4466 we have here, has a little trimmer on the back. You can control the gain by adjusting the trimmer.
MAX4466 is an operational amplifier (integrated circuit) and has no trimmer on it. I assume that you are using some module based on MAX4466. The module itself can cause the issue you are observing (distortion and no increase in gain). I would recommend connecting this module to a speaker amplifier or headphone amplifier to check if the module works correctly.
do you still have Problems with the noise?
We could have a quick look at the schematic.
Besdt regards,
Matthias
We tried LINE IN again but we could not fix the problem. We will use the MIC Input as you first suggested and leave LINE IN out. Thank you!