private static int frequency = 10000;
private static int duration = 100;
Console.WriteLine("Use keyboard arrows to adjust frequency and duration");
do
{
while (!Console.KeyAvailable)
{
Console.Beep(frequency, duration);
}

var key = Console.ReadKey(true);

switch (key.Key)
{
case ConsoleKey.UpArrow:
frequency += 100;
frequency = Math.Min(frequency, 15000);
break;
case ConsoleKey.DownArrow:
frequency -= 100;
frequency = Math.Max(frequency, 1000);
break;
case ConsoleKey.RightArrow:
duration += 100;
duration = Math.Min(duration, 1000);
break;
case ConsoleKey.LeftArrow:
duration -= 100;
duration = Math.Max(duration, 100);
break;
}
} while (true);