REM TESTLOUD.BAS, written with <3 by Ethan Busbee, 2017.

DIM freq AS LONG

CLS
PRINT "  -1 Hz:   A      +1 Hz:   Q"
PRINT " -10 Hz:   S     +10 Hz:   W"
PRINT "-100 Hz:   D    +100 Hz:   E"
PRINT
PRINT "TO EXIT, PRESS \"

freq = 37
SOUND 0, 0

DO
  LOCATE 4, 1
  PRINT USING "FREQUENCY: #####,Hz"; freq
  SOUND freq, 1

  REM GET which KEY pressed AS uppercase AND react accordingly
  KEY$ = UCASE$(INKEY$)
  SELECT CASE KEY$

    CASE "A"
      freq = freq - 1
    CASE "S"
      freq = freq - 10
    CASE "D"
      freq = freq - 100

    CASE "Q"
      freq = freq + 1
    CASE "W"
      freq = freq + 10
    CASE "E"
      freq = freq + 100

  END SELECT

  REM Bounds-checking ON the frequency
  IF freq > 32767 THEN freq = 32767
  IF freq < 37 THEN freq = 37

LOOP WHILE KEY$ <> "\"

LOCATE 7, 1
PRINT "Bye! <3"