SoX (Sound eXchange; it's in the Pandora Repo) can do a lot of things, for example:
When you run it it drops you in a shell, from there, you must first export some environment variables:
	
	
	
		
Now try to pluck a sound:
	
	
	
		
From there, you can make the Pandora help finetune your guitar:
	
	
	
		
Or create telephone sounds:
	
	
	
		
possibly appending a sequence into a wav, then play the wav.
However, I'm trying to reverse it: I get a sound in the microphone, and I want the corresponding letter. In a way, I need some information about how Commodore and spectrum transformed a tape audio into bytes.
So far, I learned that the Goertzel_algorithm is faster than FFT (Fast Fourier Transforms) and there seems to be code available but nothing I can work with at the moment . Does anybody have a shortcut into that? Can SoX do it with FIR or Hilbert commands?
				
			When you run it it drops you in a shell, from there, you must first export some environment variables:
		Code:
	
	export LD_LIBRARY_PATH=`pwd`/lib
export PATH=$PATH:`pwd`/bin
export SOX_OPTS="--buffer 4096 -q"
	Now try to pluck a sound:
		Code:
	
	bin/play -n synth 4 pluck E2
	From there, you can make the Pandora help finetune your guitar:
		Code:
	
	 for n in E2 A2 D3 G3 B3 E4; do
     play -n synth 4 pluck $n repeat 2; done
	Or create telephone sounds:
		Code:
	
	alias pause='play -n trim 0.0 0.1 remix - ' # North American Off Hook Signal Gap
pause # I need this because the pandora is silent on the first command!
play -n synth 0.1 sin 697 sin 1209 remix -  # Keypad 1 Signal
play -n synth 0.1 sin 697 sin 1336 remix -  # Keypad 2 Signal
play -n synth 0.1 sin 697 sin 1477 remix -  # Keypad 3 Signal
play -n synth 0.1 sin 697 sin 1633 remix -  # Keypad A Signal
play -n synth 0.1 sin 770 sin 1209 remix -  # Keypad 4 Signal
play -n synth 0.1 sin 770 sin 1336 remix -  # Keypad 5 Signal
play -n synth 0.1 sin 770 sin 1477 remix -  # Keypad 6 Signal
play -n synth 0.1 sin 770 sin 1633 remix -  # Keypad B Signal
play -n synth 0.1 sin 852 sin 1209 remix -  # Keypad 7 Signal
play -n synth 0.1 sin 852 sin 1336 remix -  # Keypad 8 Signal
play -n synth 0.1 sin 852 sin 1477 remix -  # Keypad 9 Signal
play -n synth 0.1 sin 852 sin 1633 remix -  # Keypad C Signal
play -n synth 0.1 sin 941 sin 1209 remix -  # Keypad * Signal
play -n synth 0.1 sin 941 sin 1336 remix -  # Keypad 0 Signal
play -n synth 0.1 sin 941 sin 1477 remix -  # Keypad # Signal
play -n synth 0.1 sin 941 sin 1633 remix -  # Keypad D Signal
	possibly appending a sequence into a wav, then play the wav.
However, I'm trying to reverse it: I get a sound in the microphone, and I want the corresponding letter. In a way, I need some information about how Commodore and spectrum transformed a tape audio into bytes.
So far, I learned that the Goertzel_algorithm is faster than FFT (Fast Fourier Transforms) and there seems to be code available but nothing I can work with at the moment . Does anybody have a shortcut into that? Can SoX do it with FIR or Hilbert commands?
	