Using a exponential curve (x^4) instead of linear mixing for the internal mixer.

src/effect_mixer.hpp

@@ -52,7 +52,7 @@ public:
 			gain = MAX_GAIN;
 		else if (gain < MIN_GAIN)
 			gain = MIN_GAIN;
-		multiplier[channel] = gain;
+		multiplier[channel] = powf(gain, 4); // see: https://www.dr-lex.be/info-stuff/volumecontrols.html#ideal2
 	}
 
 	void gain(float32_t gain)

src/serialmididevice.cpp

@@ -57,6 +57,8 @@ void CSerialMIDIDevice::Process (void)
 	int nResult = m_Serial.Read (Buffer, sizeof Buffer);
 	if (nResult <= 0)
 	{
+		if(nResult!=0)
+			printf("Serial-Read: %d\n",nResult);
 		return;
 	}