Creating a number station [closed]

This is a question about manipulating sound (wav files).

The goal is to produce something that sounds like a number station broadcast, see e.g., 4:00 in http://www.youtube.com/watch?v=EdnoAJ7KoFE

It is easy to generate a random string of numbers, and send it to the linux program espeak (with -v de for German and -w out.wav for saving the sound as a wav file.)

Now, the resulting voice is too clean to sound like a radio recording, so the challenge is to distort the sound a bit and make it sound more like a strange radio recording. Adding a little echo and some white noise maybe?

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closed as not a real question by whuber, Silvia, Artes, m_goldberg, JensMay 9 '13 at 1:26

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Is this a Mathematica-related question? If so, please add information on what you already tried and working code. –  Yves Klett May 8 '13 at 11:28
I can't imagine you'll get any spies to pay attention to you if you use random numbers... –  Oleksandr R. May 8 '13 at 14:44
Oleksandr R. It is more that I enjoy the sound, (and creep out the neighbours) :) –  Paxinum May 8 '13 at 14:46

It shouldn't be too hard to do some simple sound processing. Take an example file:

data = ExampleData[{"Sound" , "Apollo13Problem"}]


Get a short sequence of sample values from near the end of the file:

soundsamples = data[[1, 1]][[All, 110000 ;; -2000]];


It looks OK:

ListLinePlot[{soundsamples[[1]]}]


Play it without modifications:

ListPlay[soundsamples, SampleRate -> 11000]


Change the data:

ListPlay[BandpassFilter[soundsamples[[1]], {1, 2.5}], SampleRate -> 11000]
ListPlay[DerivativeFilter[soundsamples[[1]], {3}], SampleRate -> 11000]
ListPlay[GradientFilter[soundsamples[[1]], {1, .6}], SampleRate -> 11000]


Making it sound even worse shouldn't be too hard. It's making it sound better that's difficult... :)

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