 
 //respond to serial commands
 void respondToByte(char c) {
-  myTympan.print("Received character "); myTympan.println(c);
+  Serial.print("Received character "); Serial.println(c);
   
   switch (c) {
     case 'J': case 'j':

#include <Tympan_Library.h>  //include the Tympan Library

//create audio library objects for handling the audio
Tympan                    myTympan(TympanRev::E);  //do TympanRev::D (Teensy 3.6) or TympanRev::E (Teensy 4.1)
AudioInputI2S_F32         i2s_in;        //Digital audio *from* the Tympan AIC.
AudioEffectGain_F32       gain1, gain2;  //Applies digital gain to audio data.
AudioOutputI2S_F32        i2s_out;       //Digital audio *to* the Tympan AIC.  Always list last to minimize latency

//Make all of the audio connections
AudioConnection_F32       patchCord1(i2s_in, 0, gain1, 0);    //connect the Left input

  TR_Card *card_h;  //dummy handle for a card

  //Add first page to GUI
  page_h = myGUI.addPage("Basic Gain Demo");
      //Add a card under the first page
      card_h = page_h->addCard("Change Loudness");
          //Add a "-" digital gain button with the Label("-"); Command("K"); Internal ID ("minusButton"); and width (4)
