THG TIM 2015, Technical Manual

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TIM 2015 Technical Manual v1 (February 2018) Page 37
11. There is also a trade-off when using MP3 files. They need more processing than .WAV files but occupy less space on the microSD
card, meaning that MP3 files may take a shorter time to load initially. In theory the smaller files ought to mean to shorter access time
and loading time but our trials indicated this was not the case.
12. The designer tried using lower bit rates for the .WAV files and found that these gave very scratchy results. It is far better to aim for
higher quality.
13. If sound files fail to play, they may be too long. If you shorten them by removing any excess silence, you may find they will work
then. You may need to remove excess silence from other files.
14. In any 10-second voice file the actual speech, tone and pauses should not exceed 9.8 seconds. Give the Catalex player adequate
breathing space!
If you get into difficulties, do send an e-mail ( andrew_emmerson@btinternet.com ).
Catalex serial MP3 player limitations
Mick Champion reports:
A voice timing bug has come to light due the increased number of voices now available to TIM 2015. It didn’t take long to spot that the
Catalex MP3 player is at the root of the problem but unfortunately little can be done about it. The table below shows the time is takes to
complete playing the same one track ‘At the third stroke, it will be Three’. All folders contain Pat Simmons for the purpose of this
experiment.