Testing Low Pass Filters in Java:

public static double[] FirstOrderLPF (double[] input, double ratio)
{
	double[] output = new double[input.length];

	double value = 0;

	for (int i = 0; i < input.length; i++)
	{
		value = input[i] * ratio + value*(1-ratio);
		output[i] = value;
	}
	return output;
}

public static double[] SecondOrderLPF (double[] input, double ratio)
{
	double[] output = new double[input.length];

	double value = 0;
	double value2 = 0;

	for (int i = 0; i < input.length; i++)
	{
		value = input[i] * ratio + value*(1-ratio);
		value2 = value * ratio + value2*(1-ratio);
		output[i] = value2;
	}
	return output;
}


Results:


4 sample/cycle:
First order 3DB ratio = 0.7509617805480957
First order 6DB ratio = 0.5857863426208496
Second order 3DB ratio = 0.864356517791748
Second order 6DB ratio = 0.7667346000671387

8 sample/cycle:
First order 3DB ratio = 0.5857863426208496
First order 6DB ratio = 0.35640573501586914
Second order 3DB ratio = 0.6944746971130371
Second order 6DB ratio = 0.5298819541931152

16 sample/cycle:
First order 3DB ratio = 0.3318209648132324
First order 6DB ratio = 0.20199346542358398
Second order 3DB ratio = 0.4498744010925293
Second order 6DB ratio = 0.3215975761413574

32 sample/cycle:
First order 3DB ratio = 0.1793208122253418
First order 6DB ratio = 0.10701799392700195
Second order 3DB ratio = 0.26179075241088867
Second order 6DB ratio = 0.1777663230895996

64 sample/cycle:
First order 3DB ratio = 0.09365320205688477
First order 6DB ratio = 0.055086612701416016
Second order 3DB ratio = 0.14140748977661133
Second order 6DB ratio = 0.09343862533569336

128 sample/cycle:
First order 3DB ratio = 0.04792070388793945
First order 6DB ratio = 0.02794027328491211
Second order 3DB ratio = 0.0734248161315918
Second order 6DB ratio = 0.04789304733276367

256 sample/cycle:
First order 3DB ratio = 0.02424764633178711
First order 6DB ratio = 0.01407003402709961
Second order 3DB ratio = 0.037416934967041016
Second order 6DB ratio = 0.024243831634521484