[music-dsp] yamaha DX FM

[lanceboyle at qwest.net]

I had (er--have) a DX7, the original model. Not sure why since my  
playing stinks--it just happens to have come out on just about the  
day that I decided to get a keyboard. I believe that mine may have  
been one of the first production models because I distinctly remember  
there being a white stretch limo in the parking lot of the Phoenix,  
Arizona store and the buzz inside being that "someone from Yes" was  
in from Los Angeles to pick up a DX7.

I would love to know why the notes of many if not most of the DX7  
instrument settings, when played on the upper parts of the keyboard,  
took on a distinctly grainy and unpleasant sound. I don't think it  
was the DAC (bit depth, anyway), and the sound wasn't generally like  
aliasing, but rather a certain amount of inharmonic "fuzz" around  
each note. It was bad enough on some instrument settings that one  
quickly learned not to play the high notes on those instruments.

Jerry



On Jun 15, 2006, at 8:46 AM, kernel wrote:

> excuse the 80's intrusion... anyone know more about how the old DX  
> range of synths work on the inside?  I know that really they are  
> phase modulation synths.  but I'm wondering about sampling  
> frequency (28 khz?), D/A converters (so far I've seen them stated  
> as 10,12,14 & 16 bit) and whether the oscillators are wavetables or  
> maybe a sine algorithm.  did they use floating point or fixed  
> point?  but I guess there were differences across the line as my DX  
> sounds different to others I've heard (DX21 v DX100/27).
>
> thanks, kernel.
>
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