**FB01 Sysex Information**

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From: mjs@sfsup.UUCP

Subject: Re: FB-01 microtonality

Date: 27 Feb 87
01:20:52 GMT

7 Feb 87 01:20:52 GMT

In article
<13421@cca.CCA.COM> m204help@cca.CCA.COM (Keith Hedger) writes:

>In
the ads for the FBO1, it is stated that the instrument will
store

>microtonal tunings. Is this the same capability that is available
in the new

>DX7's and TX81Z's ??? Can this facility be used to actually
play using

>techniques such as Just Intonation etc. ???

>keith
hedger

Keith, I dunno about any ads, but perusing the manual here, the
FB-01 cannot

store microtonal tunings, but it can play microtonal notes (to a
resolution of

1 cent, relative to a chromatic note). If you're using a PC (of
any brand) to

control your MIDI setup, then you can do your own microtonal
scales, but the

FB-01 only knows microtonal notes.

Here's a quickie
summary of the MIDI implementation (System Exclusives only):

F0 43 2s 0C
F7 Dump Voice Bank 0

F0 43 75 0s 20 00 0x F7 Dump Voice Bank "x"

F0 43 75
0s 20 01 00 F7 Dump Current Configuration Buffer

F0 43 75 0s 20 02 xx F7 Dump
Configuration Bufffer "xx"

F0 43 75 0s 20 03 00 F7 Dump All Configuration
Memory

F0 43 75 0s 20 04 00 F7 Dump ID Number

F0 43 75 0s 2i 05 00 F7 Dump
Instrument "i" Voice Data

Notes: "s" is the system exclusive channel a
given FB-01 is to respond to (this

supports multiple FB-01's on the same
cablrts multiple FB-01's on the same cable.

"x" is a voice bank number
(0..6).

"xx" is a configuration number (0..20 decimal).

"i" is 8 + an
instrument nuber (0..7).

F0 43 1s 15 pp dd F7 Conf. Parameter Change By
MIDI Channel

F0 43 75 0s 2i pp dd F7 Conf. Parameter Change By Sys Channel +
Inst. #

F0 43 1s 15 pp 0y 0x F7 Voice Parameter Change By MIDI Channel

F0
43 75 0s 2i pp 0y 0x F7 Voice Parameter Change By Sys Channel + Inst. #

F0 43
75 0s 10 pp dd F7 Sys. Parameter Change By MIDI Channel

Notes: "pp" has
varying ranges for each of the above, and represents a

parameter
number.

"s" is as above.

"i" is as above.

"dd" is a data value,
generally 7 bits.

"x" and "y" are 4-bit data values (I dunno
why!).

EVENT LISTS

This is new stuff for Yamaha. The sequence:

F0
43 75 70

introduces an event list, and it is (of course) terminated by the F7
(EOX).

Any number of events may be enclosed in the list.

0n kk ff Note
Off with Fraction

1n kk ff vv Note On/Off with Fraction

2n kk ff vv yy xx
Note On/Off with Fraction and Duration

3n cc vv Control Change

4n pp
Program Change

5n vv After Touch

6n yy xx Pitch Bend

7n pp dd Inst.
Param. Change (1-byte)

7n pp 0y 0x Inst. Param. Change (2-byte)

In
addition, the FB-01 cae)

In addition, the FB-01 can return 3 types of
"answers" to system exclusive

requests:

F0 43 6s 02 F7 ACK

F0 43 6s
03 F7 NAK

F0 43 6s 04 F7 "cancel"

I haven't yet ascertained all the
circumstances under which these are sent.

If anyone has specific
questions, I'll be happy to answer email, but I don't

guarantee I'll be
reading this newsgroup (I have this boss, see, and he has

these expectations
that I'll actually get some work done...).

--

Marty Shannon

UUCP:
ihnp4!attunix!mjs

Phone: +1 (201) 522 XXXX (in flux; forget it for
now)

From: RAYBRO%HOLON%UTRC@UTRCGW.UTC.COM (William R(ay)
Brohinsky)

Subject: Re: Yamaha FB01 Sound Generator

Date: 24 Jan 91
12:51:00 GMT

Here, also are a few of the more important
equations:

I= deltaf/fm

where

I=modulation
index

deltaf=frequency deviation

fm=modulating
frequency

Fortunately, DX-type synths use numbers from 0-100 or 0-127 for
the

output values of each operator. Knowing this number, you can look

up
the modulation index that would result from using that number

for a modulator
in tables in the back of the book. Now the bad news:

there is no table for
the FB01, and the three tables given (with

graphs for interpolation) are for
DX7, DX-21, and CX5. Worse yet, the

values from these tables/graphs for a
modulation irom these tables/graphs for a modulation index of 1 are

70,~63,
and 97.5 (roughly). This is one thing that makes

translating 6-op (where only
four operators are used) to 4-op voices.

Next important thing, is to be
able to guess the number of significant

sidebands. Although this relies on
everything from psychoacoustics,

acoustics, and physiology to power theory,
Messrs. Chowing and Bristow

postulate that the number of sidebands to care
about is

K=I+2

So if the modulation index is 1, you should keep track of
three sidebands.

I would modify this, from logic, that as I approaches zero,
the 2 should also

[replace previous 2 lines with:]

Note that they
calculate sideband number as

c+Km,

where

c=carrier

K=sideband number
(0,1,2,...n)

m=modulation freq

n=sideband number

This way, by their
figuring, you get the carrier and three sidebands on eith

er side of it with
I=1. NOTE also that I=0 is an exception, because

an unmodulated carrier MUST
be the carrier alone! (i.e., K=0) I suspect that

the first two sidebands rise
very quickly with increasing I, which is

why it takes to at least 60 before
you get to I=1 when you have a total

of 100 or 127 max!

The only
remaining necessity for calculating sideband power are:

remember that the
negative sidebands wrap around zero (if the modulationfreq

is greater than
the carrier) or at le> is greater than the carrier) or at least approach zero
(if the modulation freq

is less than the carrier, and I is large enough, some
of them will still

wrap around zero!). This zero wrap is a large part of what
allows making

such complex spectra. If the M and C freq's are integral
multiples of

one another (even if they are both fractional, like .75 and 1.5)
then at least

some of the sidebands that wrap around zero (dependant on I)
will overlay

upper sidebands.

Note also, that any negative frequency
is just a positive frequency that

is inverted (180degrees out of phase), and
will subtract it's amplitude from

any present positive
frequency.

Then, you can figure out the amplitude of the sidebands using
bessel functions

and just subtract the negative frequency amplitudes from the
positive

frequeny amplitudes for the same |frequency|, HOWEVER:

There is
just one more bugaboo in FM:

For some reason, not explicitly stated in the
book, the negative sidebands

[read that: the LEFT sidebands] are not all in
phase, although the right

sidebands are. For the left sidebands (the lower
freq side of the carrier]

each odd sideband is NEGATIVE!

This means
that, for an I of 4 (six significant sidebands) the upper sidebands

will all
be positive, but the lower ones are

first lower SB: negative

Second lower
SB: zero (we are assuming that c=m)

thzero (we are assuming that
c=m)

third lower SB: positive (negative because it's odd, negative again
because of

the wrap around zero) and at the same freq as the
carrier

Fourth lower SB: negative and at the same freq as the first upper
sideband

fifth lower SB: positive and at the same freq as the second upper
sideband

sixth lower SB: negative and at the same freq as the third upper
sideband

The tables and figures in the book are invaluable for figuring
all this out.

My description (shot through with corrections) is rather
weak.

Note that, since the curve of the TL vs. I graphs is non-linear (I
believe

it is logarithmic, starting at zero and remaining close to the TL
axis

'til the numbers quoted above for I=1, where it starts to climb to
vertical

and parallel to the I axis) that a DX/FB/TX programmer might have to
have

a lookup table to program outputs in terms of I. This should be
switched

according to algorithm: the carrier(s) should show their outputs in
terms

of TL, and carriers should be in terms of I.

As for feedback
operators, I don't even want to think about it!

raybro

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