THG TIM 2015, Техническое руководство

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TIM 2015 Technical Manual v1 (February 2018) Page 29
If you examine the files on-screen in Audacity, you will observe that the audio in any particular .WAV file runs for a shorter length of time
than the timeslot allocated to it and is seldom placed in the file with equal lengths of silence before and after. This is deliberate; to ensure
that the voice files sound natural when played out sequentially, you must leave a short silence, at least 1/10th of a second, before the audio
starts and ends. Otherwise the Catalex chip may not play the files correctly.
Whenever you save files with Audacity, ensure that you clear all the ‘media attributes’ that it may automatically try to fill-in during the Save
dialogue. If the files include extra metadata of this kind (such as ‘genre’) the resultant files may play erratically.
Unless you are very brave or skilled, we advise you not to make any alterations to this scheme of things, otherwise commands from the
microcontroller (PIC chip) will probably fail to work. The files that you create need to be stored in a numbered folder:
01 , 02 , 03, 04 or 05
(we advise placing no more than five voices on a microSD card).
The memory size occupied by the audio files for a single voice is around 60MB.
Note that in Audacity the voice files should have the following characteristics: mono ( not stereo ), 44,100Hz, 32-bit float, maximum
amplitude between -1.0 and +1.0. We suggest sticking to mono to minimise the size of the files created. In fact it does not matter if you used
stereo files, but there is no advantage and the MONO files are obviously smaller
.
The default track created in Audacity when you press the
record button is a stereo track displayed in Waveform view with a linear vertical scale running from -1.0 (negative values) to +1.0 (positive
values), centred on zero (provided you have not changed Audacity's default for the display) .
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