[sdiy] Yamaha DXy DCO's

[Theo]

----- Original Message -----
From: Jonathan Lippard <jblippard at comcast.net>
To: Peter Grenader <peter at buzzclick-music.com>;
<synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, February 18, 2004 12:16 PM
Subject: Re: [sdiy] Yamaha DXy DCO's


> At 04:05 PM 2/17/2004 -0800, you wrote:
>
> >Now, not trying to stick up for Yamaha, BUT it's the manner in which they
> >incorporated polyphony which gave these instruments their trademark thin
> >sound - which I believe is actually cycling through single pitches at an
> >incredibly fast rate.
>
> I'd be interested in hearing you elaborate on this.  No bones to pick,
just
> curious...
>

There is just one hardware operator, it is multiplexed 96 times (6 operators
x 16 voices).
The story of cycling though pitches probably originate there.
Has nothing to do with thin sound BTW.
The DX uses a phase accumulator with a sine lookup table, just like modern
day digihell stuff.

<snip>

> Someone else noted the lack of filters on the original DX series, but I'll
> comment here--I'm willing to bet it was a tradeoff against the amount of
> processor power available at the time.  Yamaha probably could've added
> filters but it might have doubled the price of the DX-7.  Or maybe they
> just decided there were enough ways to get filtered-sounding FM tones
> without having to do the math.
>

The whole point of FM was NO FILTERS, a variable modulation index takes over
that role.
Good sounding and affordable digital filters where not doable at the time,
so pp looked for workarounds.
Various other attempts to go without filters where also made, waveshaping,
walsh? functions, (additive) Fourier synthesis...
The goal was to do digital sound synthesis with almost no processor power or
memory use.
With the DX the payback came as storable patches, 16 voices at a price even
musicians could afford.
Adding filters would more likely have raised the price by a factor 10.

Cheers
Theo


> -Jonathan
>
> END OF LINE.
>
>