home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Sound Sensations!
/
sound_sensations.iso
/
demos
/
gfmanual
/
part07.mnl
< prev
next >
Wrap
Text File
|
2002-07-28
|
24KB
|
727 lines
Timing Section 8-1
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
START OF PART7.MNL
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-2
TIMING
------
Timing is a subject that you should thoroughly understand in
order to use GFMUSIC (or any sequencer) effectively. At first it
can be somewhat confusing but if you stick with it and
experiment, you will master it.
First, the basic concept to understand is that unlike real life,
a sequencer deals in finite increments of time. In real life a
note can be played at any time. In computerland, a note(s) can
only be played during a 'window' of time. However, computers can
process data so fast with windows so small that for all practical
purposes the human ear can not usually distinguish the difference
in time between one window and the next.
The way a sequencer works is to break up each measure into a
specific number of 'steps'. If you attempt to break up the
measure into too few steps, the music doesn't have enough
'resolution' to sound 'realistic'. For example, if we only break
up the measure into 4 steps then we could not play notes on
anything less than the 'quarter note beat'. I.e. eighth notes
could not exist. On the other hand, if you attempt to break up
the measure into too many steps, the computer will spend so much
of its resources just keeping track of where it is, it could not
get around to playing the notes. So the idea is to strike a
balance such that we break up the measure into enough windows to
sound realistic, but not so many steps such that the computer
spends all of its time doing housekeeping chores as opposed to
playing music.
In addition, we need to break up a measure into a number of steps
that makes sense. Some numbers of steps per measure make more
sense than others. For example, if a measure consisted of 100
steps, then a half measure (half note) would consist of 50 steps,
a quarter note would consist of 25 steps, and an eighth note
would consist of 12.5 steps. A half step doesn't make much sense
as the computer would have to ultimately choose a whole number of
steps. I.e. the eighth note would have to played at either step
12 or 13. The half step difference may even sound odd to the
ear. On the other hand, If we choose 96 steps per measure, the
measure breaks up nicely all the way down to the 32nd note level
(a 32nd note would be 3 steps long). And dividing up the measure
into 192 steps breaks up even better as shown by the following
table :
- whole note 192 steps (whole measure)
- half note 96 steps
- quarter note 48 steps
- eighth note 24 steps
- 16th note 12 steps
- 32nd note 6 steps
- 64th note 3 steps
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-3
With 384 steps per measure (2 times 192) we can get down to a
meaningful 128th note. But on the other hand, could your ear
(or your audience's ear) detect the difference between a 128th
note and a 64th note. And could you accurately play one vs the
other ??
There are other breakups of the measure that make sense. All
examples here will use 192 steps per measure. 192 steps are used
in examples because the very popular Dr. T sequencer often uses
96 steps in their examples and 192 steps is simply twice that
(i.e. provides twice the resolution). Those of you familiar with
Dr. T's sequencer will feel right at home here.
Timing studies of GFMUSIC indicate that it will run quite nicely
at 192 steps per measure even at very fast tempos on an IBM PC or
compatible running at normal speed (4.77 MHz). Most newer PC
clones will run at 8 MHz or even faster (often called 'Turbo
Mode'). These machines will be able to process sequences using
256 steps per measure rather easily and can go faster than that
depending on how 'active' the music is. If you have a PC with a
'286' processor, you can run even faster. On the other hand, it
is debatable that most ears will be able to 'appreciate' anything
past 192. But your own ear is the judge. Now on to the
discussion of timing as it pertains to how to make music.
Let's assume that we will use 192 steps per measure. If we are
in 4/4 time, then each quarter note will be 48 steps long, each
1/8th note will be 24 steps long, etc. How much time that is
depends on the tempo. The slower the tempo, the longer the
amount of time for each step. But really you don't have to worry
about this aspect. All you have to remember at this point is how
many steps constitute a measure (whole note), 1/4 note , 1/8th
note, etc.
For 4/4 time, 192 steps per measure is a good setting. Where do
we set this ?? On the SET TIME screen which is option 12 of the
Main Menu. At this point you should go to this screen by
selecting option 12 from the Main Menu.
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-4
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SET TIME
-------
STEPS / MEASURE (1-512) | 192 |
STEPS / MIDI-CLOCK (1-16) | 2 |
BEATS / MEASURE (1-32) | 4 |
MIDI-CLOCK EXT/INT/OFF (E,I,O) | O |
BEATS / MINUTE | 120 |
ECHO CHNL (0=OFF, 1-16, >16=AS IS) | 0 |
--------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On this screen you will see that you can enter values for :
- Steps / Measure
- Steps / Midi-Clock
- Beats / Measure
- Midi-Clock Ext/Int/Off
- Beats / Minute
- Echo Channel
On this screen we would set the Steps/Measure field to 192 and
Beats/Measure to 4. The Beats/Minute field is 'tempo' but does
not really affect what we are talking about now. The other
fields will be explained later.
Now load song GFDEMO1. The timing parameters are saved with a
song and GFDEMO1 was created/saved with 192 steps/measure. After
loading GFDEMO1, go into EDIT on Sequence CHORDS 1-12.
Looking at the EDIT screen for CHORDS 1-12 notice the MEAS and
STEP fields for each event (right side of screen). The first 3
events all start at time zero and have a MEASure of 1 and STEP of
1. The MEAS and STEP fields are calculated and shown on the EDIT
screen as if that sequence were the only thing ever played. I.e.
this sequence may be played at measure 14 when actually played,
but when shown on the edit screen it is shown as if it were the
only sequence in the song. Now notice events 4-6. They have a
MEAS and STEP of 2 and 1 respectively. This is because they all
start 192 steps after the 1st 3 events and 192 steps is one
measure long (because we said so on the SET TIME screen).
Sequence CHORDS 1-12 has all of its events on a MEASure boundary
because each chord is exactly 1 measure long.
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-5
Now END edit for CHORDS 1-12 and edit sequence QUARTER NOTES.
Notice that the TIME field for each note is 48 (corresponding to
1/4th of a measure or 1/4th of 192). Also notice that Event 2
has a MEASure of 1 and a STEP of 49. That is, event 2 (the 2nd
note) starts at step 49 of the first measure. STEP 49 is really
the beginning of the 2nd beat of the measure. For 4/4 time using
192 steps per measure, events starting on the '1/4 note boundary'
will start on STEP 1, 49, 97, and 145. You will quickly master
these numbers although at first you may find it difficult. The
1/8th note 'boundary' is STEPS 1,25,49,73,97,.....169. Again,
you will eventually master these numbers also. The half note
boundary is STEPs 1 and 97. Or you can think of it this way, for
quarter notes, the first quarter uses STEPS 1 thru 24 so the
second quarter note will begin at 25 (1 higher than 24) and
contain 24 steps (or steps 25 thru 48 inclusive). All
boundaries start at an odd number.
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-6
So how do we set things up for 3/4 time ?? Easy. If the song
you are creating is in 3/4 time then the time you want to set on
the SET TIME screen is 3 times 48, or 144. And beats/measure
would be set to 3.
2/4 time ?? Set Steps per measure to 96 (2 times 48).
5/4 time ?? Set Steps per measure to 240 (5 times 48).
3/8 time ?? Set Steps per measure to 72. I.e. if a 1/4 note is
48 steps then a 1/8th note is 24 steps. 3 beats per measure is 3
times 24.
All of the above assume that a quarter note is 48 steps long. If
you are strictly using the sequencer as a kind of high tech tape
recorder, then the above does not really matter. You simply
record and overdub to your heart's content. However, if you want
to correct the timing of the sequences and/or have them loop,
then you will need to know how steps per measure impacts the MEAS
and STEP calculations in edit. Because it is in EDIT that you
will correct the timing so that a sequence is the exact length
you need for your song. One of the most important things you will
do is to give the last event (always a Null Event) the proper
start time to make the sequence the correct length. For example,
if you want a sequence to be exactly 4 bars long then the MEAS
STEP fields of the last event should have values of 5 and 1
respectively.
If your song/sequences shift time signatures then you will have
to manually reset the steps/measure on the SET TIME screen before
editing sequences with different time signatures in order to get
the correct MEAS and STEP readouts.
In order for the timing to work correctly, the BEATS / MEASURE
field on the SET TIME screen also needs to be set correctly. It
should divide evenly into STEPS/MEASURE. As a general rule
though, simply set it to what you think it should be based on the
time signature the song is in. For example, if in 4/4 time (4
beats per measure with each 1/4 note getting one beat) just set
BEATS/MEASURE to 4. If 3/4 time, set STEPS/MEASURE to 144
(3/4ths of 192) and BEATS/MEASURE to 3. Think about it and
experiment. The following table is provided for common time
signatures for your convenience. They are based upon providing
good resolution for a PC running at normal speed (4.77 MHz). If
you are using a clone that will run faster ('Turbo' mode), or
have a machine with a 286 or faster processor, you could usually
double the STEPS/MEASURE value, but your ear may not be able to
distinguish any difference. One thing to remember.... If you
originally develop/record a song with one setting of
STEPS/MEASURE and later change it, you will have to change the
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-7
tempo or use the Expand/Compress feature of edit to either
lengthen or compress each sequence by the same factor that you
changed STEPS/MEASURE by.
If you are using Midi-clocking to controll a drum machine (Midi
clock Internal), or are using a drum machine to controll the
sequencer (Midi clock External), then you will also need to set
the STEPS/Midi-CLOCK correctly as well. The Midi spec says that
if you are using Midi Clocking, then you should send (or expect
to receive) 24 Midi Clock 'signals' per quarter note. If a
quarter note is 48 steps, then you should set STEPS/Midi-CLOCK to
2 (48/24). Just remember, determine how many steps per quarter
note and then divide by 24 to get the STEPS/Midi-CLOCK value.
This only applies if you are using either external or internal
Midi-clocking.
For now keep everything simple. Experiment later. Use the
following table for your timing settings.
SET TIME Screen Values To Set
Time
Signature STEPS/MEASURE BEATS/MEASURE STEPS/Midi-CLOCK
--------- ------------- -------------- ----------------
4/4 192 4 2
3/4 144 3 2
5/4 240 5 2
2/4 96 2 2
3/8 72 3 2
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-8
Midi clocking is a subject that you should know about also.
GFMUSIC supports Midi clocking from either an external source
(usually a drum machine) or will provide clocking for an external
device (again, usually a drum machine). The way Midi clocking
works is this : 24 times per quarter note the drum machine or
sequencer will send out a Midi clock 'signal'. This tells other
devices on the line that 1/24th of a quarter note's worth of
time has elapsed. The 'receiver' of the clock signal would then
advance its clock by that amount of time. GFMUSIC will either
send or react to Midi Clock signals while in play/record mode.
To have it send/provide the Midi clocking you should set the
Midi-CLOCK EXT/INT/OFF field to "I" on the SET TIME screen
(option 12 of the main menu). To have GFMUSIC react to Midi
Clocking from another device such as a drum machine then set this
field to "E" (for External). The last possible setting is "O"
(for Off).
Something to note here with respect to Drum machines. One thing
you may want to do is have all of your drum patterns as sequences
within GFMUSIC. In this way you do not have to worry about
clocking and alot of the setup that you may have to go thru with
the drum machine. One way to do this is to connect your drum
machine to GFMUSIC and have the drum machine play the patterns
while GFMUSIC records. When recording drum patterns this way you
will want to have either the drum machine or GFMUSIC provide Midi
clocking in order to get the pattern recorded with the correct
timing.
If you have a drum machine that will send or react to Midi
Clocking, connect it to the PC and try different settings of
STEPS/Midi-CLOCK and Midi-CLOCK EXT/INT/OFF while playing song
GFDEMO1.
**************************************************************
When you save a song, all of the timing information that you see
on the SET TIME screen is saved along with the song.
If you later LOAD the song using the Clear option of LOAD, this
information is read in and replaces whatever the current settings
are.
Loading a song using the Free option, or loading an individual
sequence from a song will NOT disturb current timing settings.
***************************************************************
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-9
Here is the way GFMUSIC operates when it is providing/reacting to
Midi Clocking :
If GFMUSIC is providing the clocking (Midi Clocking is Internal),
it will send a Midi Start command when you leave LOAD mode and
enter Play/Record mode. When in play/record mode, if you press
the space bar (to pause the song) then GFMUSIC will send a Midi
STOP command. When you press the space bar again to have the
song continue, then GFMUSIC will send a Midi Continue command.
When you leave play/record mode (by pressing ESCape twice) and go
back to LOAD MODE, then GFMUSIC will send a Midi STOP command.
When GFMUSIC is reacting to Midi Clocking (Midi Clocking is
External, such as when the Drum Machine is providing the
clocking) then the following occurs : When you leave LOAD Mode
and enter Play/Record mode, then GFMUSIC waits for a Midi Start
command before playing anything. When the Midi Start command is
received then the sequences that were loaded in LOAD mode will
start. After receiving the START command, then if a Midi STOP
command is received the following happens :
First, all sequences are stopped. Then, if a Midi Continue is
received, the song picks up again where it left off. However, if
a Midi START command follows the STOP command, then GFMUSIC will
advance to the beginning of the next measure and continue
playing.
Depending on your familiarity with Midi, this may/may not mean
much to you. However, if you are new to Midi, it will eventually
sink in, especially if you research Midi by reading the many
publications available on it (both periodicals and books). In
addition, at this point it may still be somewhat fuzzy, but after
you gain more experience with GFMUSIC you should come back and
reread this section.
You probably noticed that the Set Time Screen is where you set
the Echo Channel. Echo Channel is discussed elsewhere. See the
index.
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-10
THE METRONOME
-------------
Now just a short word about the metronome. The built in
metronome uses the speaker on the PC. If there is little or no
play activity then the metronome works reasonably well. However,
when playing music with more than a minimal amount of 'activity',
the metronome may become unreliable. This is because play
processing takes priority with GFMUSIC, and if push comes to
shove, the metronome will not be sounded because the sequencer
thinks it is more important to play the music at the correct
time. If you have a "Turbo" clone or 286 machine, it stays more
reliable. If you have a drum machine, a better technique is to
create a sequence called METRONOME and include it in all of your
songs. This sequence is simply a beat with a drum. It is
completely reliable, and, much more pleasant to listen to than
the PC speaker. If you do not have a drum machine you can still
create a metronome sequence. You may want to use a high note on
the synthesizer for the note to sound as the metronome.
In either case, you can create METRONOME as a sequence and then
save it as an individual sequence (maybe use songname METRO).
Whenever you get ready to put together a new song, load sequence
METRONOME from song METRO using the LOAD SEQUENCE feature that
was discussed earlier. I.e. option 6 from the main Menu.
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
Timing Section 8-11
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
END OF PART7.MNL
COPYRIGHT (C) 1988 Gerald H. Felderman Tampa, FL
