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Last modified on 13 January 2019, at 13:08

Software Speech Synthesizers

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Software Speech Synthesizers

With some clever programming it is possible to program a software Speech Synthesizer with good results.

These programs use pre-recorded allophones, unlike as with the hardware based SP0256 speech synthesizer chip, the allophones aren't computed an the fly. However, the overall result is the same: One can combine allophones to produce any kind of words and sentences, the software solution requires more memory and more CPU load though.

Speech! uses about 8K of memory for player and sample data. The samples are stored as packed 4-bit values to send to the AY. To play the speech delay loops are often used to control the frequency at which the AY is updated, and therefore the frequency of the sample. However, when Speech is playing the CPU time is effectively used completely until it is done, unless the player could be modified?

Games believed to use Software Speech Synthesizer

Note 1 - This list is very probably incorrect (Ghostbusters and Robocop were also listed here, which was incorrect, both games contain digitized speech, not synthesizing. Same may apply for LastV8, this isn't verified yet though)

Note 2 - Does LastV8 contain any speech at all? The version from ftp nvg doesn't seem to have any speech in the intro... though maybe there is speech later in the game (?)

Note 3 - LastV8 does contain some (unused) code that uses Port FBEC-FBEE (for unknown purpose, possibly SIO transfers, or for PDS development system). Maybe somebody incorrectly assumed that this I/O Ports were used to access a hardware based speech synthesizer (which use similar I/O ports), and then, more incorrectly described the game to include a software speech synthesizer (confusing HW and SW).

Games using Digitized Speech (Samples)

Digitized sound means a simple sound recording (similar to modern WAV files on a PC). Unlike allophone-based speech synthesizers, this method requires a lot of memory, typically allowing only a few words to be stored.

Many (although not all) games written by The Oliver Twins featured digitized speech.