Microtuning with FM synthesizers and SCALA?

We are working on an alternate tuning project at Evergreen State
College in Olympia, WA that is based on the Golden Ratio (usually
referred to as "Phi"). We're trying to do something similar to what
John Chowning did with Stria: create a scale based on ratios of Phi
powers instead of on powers of 2, and then apply modulator signals
that are related in frequency by Phi powers to the carrier.

So far we have closely approached what we want to do by using the FM-
7 software in conjunction with an Ensoniq ASR-10 Sampler. FM-7 will
allow you to create a number of modulations of the tones you play
from the keyboard. FM-7 will also allow you to microtune an octave
of tones; it then applies this scale to all octaves. Unfortunately,
this is not exactly what we want to do. In order to create a true
Phi-based scale across the whole keyboard, we have to be able to re-
tune each key in all octaves individually, and FM-7 doesn't seem to
allow that.

We've started to work with the MAX object programming language, and
it appears that MAX may allow us to do both FM synthesis and the key-
by-key microtuning of the whole keyboard, but we're not sure because
we haven't done it yet.

It would be nice to have a synthesizer that would do all of what we
want to do. According to what we have been able to find out through
our Web research, Yamaha once made a series of keyboard synthesizers
(DX-7II, DX-11, DX-27, SY-77, SY-99) that will do both FM and some
degree of microtuning. We're particularly interested in the last 3
synths mentioned because they're currently available on ebay.
Unfortunately, from the manuals posted on-line at the Yamaha website,
it's really hard to tell whether we'd be able to do the type of
microtuning we want with these synths. It looks like the DX-27 won't
do it, but the SY-77 and SY-99 might.

Apparently another possibility is to use Manuel Op de Coul's Scala
program to re-map the keyboard of one of these synths.
Unfortunately, I can't tell from the Scala website and the Scala help
file whether we can really do it. The Scala web page lists the DX-27
as a synth to which it can export tuning data, and says in
parentheses "both octave and full keyboard bulk data". The reference
to "full keyboard bulk data" sounds like what we want to do, but none
of the Scala documentation actually shows you how to do it.

To re-map the whole keyboard, we would first have to specify a set of
ratio values or cents values that would give a unique value for each
key on the keyboard. For the keys below the Middle C key, these
ratios would be much less than 1 (in cents they would be more and
more negative). Then we would have to specify how each of these
ratios (cents values) were to be mapped to the keyboard (basically,
which keyboard key to start with). It's not at all clear from the
Scala documentation how we would do this. Do we do it with both a
scale file and a keyboard mapping file? If so, how are the two
linked?

If anybody could help with any of this, it would be appreciated.
Also, if anyone knows how to get ahold of Manuel Op de Coul or a
Scala expert by e-mail, that might help.

For controlling the keys of Midi instruments with
"free frequencies" the best Midi Data format is:
*Midi Single Note Tuning Change Real Time*.
I know only two synths which support this Midi data format:

1. The "Virus" of Access, see
www.kemper-digital.com

2. The "FM7" of Native Instruments, see:
www.native-instruments.de

The first one is a physical instrument,
the second is a virtual instrument.

(Maybe there exist also other synths, but I don't know them).

The Virus has been tested by myself, the FM7 has not been tested by
myself, but I got this information by Michael Kurz of Native
Instruments:

michael@native-instruments.de

*Midi Single Note Tuning Change Real Time* controls with a fineness
of 16,384 steps per halftone and it changes the frequencies even for
ringing notes, at it is a real time message.
The Virus supports this fineness exactly. I don't know the tuning
fineness of the "FM7" but I believe that it will be fine enough for
your requirements. In doubt ask Michael Kurz (see above).

If you want to control a virtual Instrument with an application on
the same computer, you have to connect it with a "Loopback", for instance
"Midi Yoke". I have never tried this, if you don't know how to use
it, please ask Michael, too.

I hope with SCALA of Manuel Op De Coul it will be possible to send tuning
messages with *Midi Single Note Tuning Change Real Time*. In other case:
We possess an own programme for sending tuning messages, but this is not
"for free" as it performs also gliding tuning changes and self-correcting
tuning programs.

If you would like to get additional informations, please write me
directly.

Best

Werner Mohrlok
Hermode Tuning

> -----Urspr�ngliche Nachricht-----
> Von: yamatman [mailto:yamatman@yahoo.com]
> Gesendet: Dienstag, 15. M�rz 2005 17:54
> An: tuning@yahoogroups.com
> Betreff: [tuning] Microtuning with FM synthesizers and SCALA?

> We are working on an alternate tuning project at Evergreen State
> College in Olympia, WA that is based on the Golden Ratio (usually
> referred to as "Phi"). We're trying to do something similar to what
> John Chowning did with Stria: create a scale based on ratios of Phi
> powers instead of on powers of 2, and then apply modulator signals
> that are related in frequency by Phi powers to the carrier.
>
> So far we have closely approached what we want to do by using the FM-
> 7 software in conjunction with an Ensoniq ASR-10 Sampler. FM-7 will
> allow you to create a number of modulations of the tones you play
> from the keyboard. FM-7 will also allow you to microtune an octave
> of tones; it then applies this scale to all octaves. Unfortunately,
> this is not exactly what we want to do. In order to create a true
> Phi-based scale across the whole keyboard, we have to be able to re-
> tune each key in all octaves individually, and FM-7 doesn't seem to
> allow that.
>
> We've started to work with the MAX object programming language, and
> it appears that MAX may allow us to do both FM synthesis and the key-
> by-key microtuning of the whole keyboard, but we're not sure because
> we haven't done it yet.
>
> It would be nice to have a synthesizer that would do all of what we
> want to do. According to what we have been able to find out through
> our Web research, Yamaha once made a series of keyboard synthesizers
> (DX-7II, DX-11, DX-27, SY-77, SY-99) that will do both FM and some
> degree of microtuning. We're particularly interested in the last 3
> synths mentioned because they're currently available on ebay.
> Unfortunately, from the manuals posted on-line at the Yamaha website,
> it's really hard to tell whether we'd be able to do the type of
> microtuning we want with these synths. It looks like the DX-27 won't
> do it, but the SY-77 and SY-99 might.
>
> Apparently another possibility is to use Manuel Op de Coul's Scala
> program to re-map the keyboard of one of these synths.
> Unfortunately, I can't tell from the Scala website and the Scala help
> file whether we can really do it. The Scala web page lists the DX-27
> as a synth to which it can export tuning data, and says in
> parentheses "both octave and full keyboard bulk data". The reference
> to "full keyboard bulk data" sounds like what we want to do, but none
> of the Scala documentation actually shows you how to do it.
>
> To re-map the whole keyboard, we would first have to specify a set of
> ratio values or cents values that would give a unique value for each
> key on the keyboard. For the keys below the Middle C key, these
> ratios would be much less than 1 (in cents they would be more and
> more negative). Then we would have to specify how each of these
> ratios (cents values) were to be mapped to the keyboard (basically,
> which keyboard key to start with). It's not at all clear from the
> Scala documentation how we would do this. Do we do it with both a
> scale file and a keyboard mapping file? If so, how are the two
> linked?
>
> If anybody could help with any of this, it would be appreciated.
> Also, if anyone knows how to get ahold of Manuel Op de Coul or a
> Scala expert by e-mail, that might help.

As far as I know the FM7 does allow full keyboard retuning. But as
Werner wrote you need a MIDI loopback to send data to it from another
program.

In Scala, type "set synth 107" to select the MIDI Tuning Standard bulk
dump. If it doesn't work, then "set synth 1" for the single note
variant, or go to Edit:Options:MIDI and select Model.
Then File:Send tuning will send the tuning. But first you need to
setup Megamid's output device to the same loopback device as you've
set FM7's input device.

> To re-map the whole keyboard, we would first have to specify a set of
> ratio values or cents values that would give a unique value for each
> key on the keyboard.

No, it's the purpose of the keyboard mapping to take care of this.
(Press F1 and enter or click on Mappings.)

> Do we do it with both a
> scale file and a keyboard mapping file? If so, how are the two
> linked?

Yes, but you can omit the keyboard mapping when in doubt. It
determines which scale degree is mapped to which MIDI note number.
You can contact me privately if it's not clear.

Manuel