[OnePlus 3T ROMs, Kernels, Recoveries, & Other Deve] :
I want to emphazise [MENTION=1444259]endursa[/MENTION]'s last sentence. (I'm no native English speaker, but I'm pretty sure "others" is more then me.)

Yesterday I was using my op3t in speakerphone mode in my trailor while the thunderstorm makes really bad noise on the tent in front of the trailor. This is really loud: a light summer rain sounds like f3 - f4 - yesterday there wqs really strong rain. When the rain increased I was talking louder and louder. Untill my call interlocutor (phrase?) asked my, why I'm talking that load...

In deed I'm using my headset really seldom (for longer tasks), since speakerphone is working well for me.

This is - of course - only verified with my carrier and my interlocutors. This may differ - I don't know.

Honestly I hate androids way of implementing and configuring alsa (no matter if conf or xml versions). I have a hard time remembering contexts I hate, so I have no ad-hoc solution for you. But I'm sure it's easy to increase mic volume if you find the device - it should be one of this:

ingo@adler /usr/local/src/cm14/device/oneplus/oneplus3t $ grep value audio/mixer_paths_tasha.xml |grep -i volume <ctl name="LINEOUT1 Volume" value="13" />
<ctl name="LINEOUT2 Volume" value="13" />
<ctl name="LINEOUT3 Volume" value="13" />
<ctl name="LINEOUT4 Volume" value="13" />
<ctl name="HPHL Volume" value="20" />
<ctl name="HPHR Volume" value="20" />
<ctl name="RX0 Digital Volume" value="84" />
<ctl name="RX1 Digital Volume" value="84" />
<ctl name="RX2 Digital Volume" value="84" />
<ctl name="RX3 Digital Volume" value="84" />
<ctl name="RX4 Digital Volume" value="84" />
<ctl name="RX5 Digital Volume" value="84" />
<ctl name="RX6 Digital Volume" value="84" />
<ctl name="RX7 Digital Volume" value="84" />
<ctl name="RX8 Digital Volume" value="84" />
<ctl name="ADC1 Volume" value="12" />
<ctl name="ADC2 Volume" value="12" />
<ctl name="ADC3 Volume" value="14" />
<ctl name="ADC4 Volume" value="14" />
<ctl name="ADC5 Volume" value="12" />
<ctl name="ADC6 Volume" value="12" />
<ctl name="DEC0 Volume" value="84" />
<ctl name="DEC1 Volume" value="84" />
<ctl name="DEC2 Volume" value="84" />
<ctl name="DEC3 Volume" value="84" />
<ctl name="DEC4 Volume" value="84" />
<ctl name="DEC5 Volume" value="84" />
<ctl name="DEC6 Volume" value="84" />
<ctl name="DEC7 Volume" value="84" />
<ctl name="DEC8 Volume" value="84" />
<ctl name="IIR0 INP0 Volume" value="54" />
<ctl name="Tert MI2S LOOPBACK Volume" value="1" />
<ctl name="Tert MI2S LOOPBACK Volume" value="1" />
<ctl name="IIR0 INP0 Volume" value="54" />
<ctl name="IIR0 INP0 Volume" value="54" />
<ctl name="DEC7 Volume" value="111" />
<ctl name="ADC5 Volume" value="12" />
<ctl name="ADC1 Volume" value="12" />
<ctl name="ADC5 Volume" value="12" />
<ctl name="RX0 Digital Volume" value="81" />
<ctl name="HPHL Volume" value="19" />
<ctl name="HPHR Volume" value="19" />
<ctl name="ADC2 Volume" value="18" />
<ctl name="ADC2 Volume" value="12" />
<ctl name="ADC2 Volume" value="12" />
<ctl name="ADC3 Volume" value="8" />
<ctl name="ADC4 Volume" value="8" />
<ctl name="RX1 Digital Volume" value="81" />
<ctl name="RX2 Digital Volume" value="81" />
<ctl name="HPHL Volume" value="20" />
<ctl name="HPHR Volume" value="20" />
<ctl name="ADC3 Volume" value="8" />
<ctl name="ADC4 Volume" value="8" />
<ctl name="IIR0 INP0 Volume" value="54" />
<ctl name="RX1 Digital Volume" value="81" />
<ctl name="RX2 Digital Volume" value="81" />
<ctl name="HPHL Volume" value="20" />
<ctl name="HPHR Volume" value="20" />
<ctl name="ADC3 Volume" value="8" />
<ctl name="ADC4 Volume" value="8" />
<ctl name="IIR0 INP0 Volume" value="62" />
<ctl name="RX1 Digital Volume" value="81" />
<ctl name="RX2 Digital Volume" value="81" />
<ctl name="HPHL Volume" value="14" />
<ctl name="HPHR Volume" value="14" />
<ctl name="ADC4 Volume" value="10" />
<ctl name="ADC5 Volume" value="8" />
<ctl name="ADC4 Volume" value="11" />
<ctl name="ADC5 Volume" value="11" />
<ctl name="ADC4 Volume" value="11" />
<ctl name="ADC5 Volume" value="11" />
<ctl name="ADC2 Volume" value="12" />

You find this config file on your device in /system/etc/mixer_paths_tasha.xml

I'm not trolling or try to offend you, but I'm completly busy with bringing up the next build, and I don't want to keep you waiting till November.

When increasing the values be very careful - it's better to increase in many small steps, then breaking some hardware by one (too large) step. I'm not sure for mics, but speaker's hardware can be broken by the values in mixer_paths. I suggest to increase the values by not more then 5% for each step.

I'm not sure, if the input device changes from gsm calls and volte calls, but you should see something (I hope it includes the symbolic names from mixer_paths).

It would be awesome, if you report back.

Good luck!