Re: Echo II sound cards

[mjmahon@aol.com (Michael J. Mahon)]

Roy replied:

>Michael J. Mahon wrote:
>
>> Bill Garber wrote:
>> 
>> 
>>>"Exegete" <millers@noneofyourbusiness.com> wrote in message
>>>news:406454e9$1_5@corp.newsgroups.com...
>>>: They use a 6522 to address two AY-3-8913 chips.
>>>: If memory serves, that chip has three "voices" and a "white
>>>noise"
>>>: generator.
>>>
>>>Really?, I thought that was the Mockingboard.
>>>I'm looking at an Echo IIb and it has none of
>>>those chips. Of course I don't have a straight
>>>Echo II so I can't really disagree.
>> 
>> 
>> The Echo II has only the TI "Spean'n'Spell" synthesis chip,
>> but can be used to play digitized sound and to make non-speech
>> sounds, within limits.
>> 
>> The Echo II+ has both the TI chip and two AY-3-8910's for
>> Mockingboard capability.  (I don't know whether it was actually
>> software compatible with the Mockingboard.)
>
>MIchael,
>I hadn't noticed the TI chip.
>If I'm reading it right, it's a TSP5220CNL
>But there's also a TI SN74LS92N - I assume that's a logic chip of some type.

Yes, it's the 5220, a 600-mil-wide chip--24 pins or so,

It was the first single-chip LPC (Linear Predictive Coding) speech
synthesis part.  It uses time-varying filters to simulate the human
vocal tract.

It requires considerable computation to compute the filter settings
to create good speech, so this part of the job was done offline with
a mainframe (at the time).

Although it is geared to producing noises made by the human vocal
tract, with proper filter coefficients it can be made to make some
pretty wierd noises--even wierder than some people can make.  ;-)

-michael

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