More on the 'fade' word
Neil Walker
I was happy to see that Ted Kirk had found a use for my
'fade' and 'swell' words (published in Hints and Tips AMPLINEX 021). Ted's
suggestion (Hints and Tips AMPLINEX 022) on the use of the words is fine - it
will give a drop in volume on a different curve to the original word and down
to a lower level. Perhaps my explanation was not as clear as it should have
been - so may I explain how the words came about, which might help clarify things.
During the programming of 'Funny Valentine' (Music AMPLINEX
021) I realised that the result was going to fall short of what was needed. It sounded
rather clinical: there was no way of controlling a single note once it was
started, all control being in the hands of the amplitude and pitch envelopes.
The two words were an attempt to resolve this problem, to
enable a point to be chosen, during a note, to start variations in the volume
level up and down rather like a dynamic amplitude envelope imposed on top of the
system amplitude envelope.
I tried it out on a short piece of music and found that the
words work. However, they are a right pain to use, needing careful working out
of note lengths, how much you want the volume to drop or rise, and need
constant resetting of ','. So they did not get used in 'Valentine' - I had
enough problems trying to recognise the notes working from a record. It is a
gift I don't have and took me ages.
However the words do demonstrate that it is possible to get
some dynamics into a note at your chosen point. As with many AMPLE words they
may be modified to do what you want.
The first version of the 'fade' word was:
"fade" [
FOR( 128 COUNT #- v1 /) FOR
% or 127 COUNT if it suits
]
FOR( 128 COUNT #- v1 /) FOR
% or 127 COUNT if it suits
]
which when called with
2, C 23 fade
reduces the volume level by 23.
Each time round the loop the volume is reduced by the value
of COUNT - in this case reducing the volume by 23 over a note of 48. That is,
there are 23 holds of length 2, making (including the C) a total note length of
48. The maximum for this note length would be with a setting of '1,' and,
starting immediately after striking the note, 47 holds - giving a reduction of
47.
This works quite well but, for more controlled use, another
number was introduced to give a choice of adding an offset to COUNT. This may,
as Ted suggests, be multiplied with COUNT (or divided or subtracted or used
with INDEX) to get the effect you might be after - it depends on the result YOU
want. If the number is 0 the word acts as the one shown above.
I was thus incorrect in saying the number was the amount the
volume is reduced, as COUNT needs to be taken into consideration - sorry.
The actual sound is very dependent on the tempo: with a long
slow note a lot can be done; in faster pieces the effect can be as Ted found -
the note rapidly drops down to a lower value. This, though useful, can be a difficulty
- juggling the amount you want to drop in the time available for the note. The
real time that the note is sounding needs to be considered: notes that lasts a
fraction of a second are best dealt with by the system words.
The following four words are another variation on the same
theme. The additional word 'vol' keeps track of the current volume setting, and
the original ',' setting is restored after use. The '/' is set to 2, though
this may be altered.
"v1" [#11 vol#! 1VOICE VOL]
"vol" [GVAR]
"fade" [
0 MVAL? FRAME
2 FVAR#? 8FVAR#!
2 % ',' setting - may be changed
2FVAR#!
MVAL!
#12 #212 #12 #* 2#/ #2
#213 #12
FOR( #11 vol#? #12 #- v1 / )FOR
#2 ,
% Takes 2 numbers: amount taken from
% VOL (remembering COUNT)
% on each hold and number of holds
% timed on last ',' setting.
% Restores ',' to last value.
]
0 MVAL? FRAME
2 FVAR#? 8FVAR#!
2 % ',' setting - may be changed
2FVAR#!
MVAL!
#12 #212 #12 #* 2#/ #2
#213 #12
FOR( #11 vol#? #12 #- v1 / )FOR
#2 ,
% Takes 2 numbers: amount taken from
% VOL (remembering COUNT)
% on each hold and number of holds
% timed on last ',' setting.
% Restores ',' to last value.
]
"swell" [
0 MVAL? FRAME
2 FVAR#? 8FVAR#!
2 % ',' setting - may be changed
2FVAR#!
MVAL!
#12 #212 #12 #* 2#/ #2
#213 #12
FOR( #11 vol#? #12 #+ v1 / )FOR
#2 ,
% Takes 2 numbers: amount added to
% VOL (remembering COUNT)
% on each hold and number of holds
% timed on last ',' setting.
% Restores ',' to last value.
]
0 MVAL? FRAME
2 FVAR#? 8FVAR#!
2 % ',' setting - may be changed
2FVAR#!
MVAL!
#12 #212 #12 #* 2#/ #2
#213 #12
FOR( #11 vol#? #12 #+ v1 / )FOR
#2 ,
% Takes 2 numbers: amount added to
% VOL (remembering COUNT)
% on each hold and number of holds
% timed on last ',' setting.
% Restores ',' to last value.
]
It is interesting to note that it is possible to re-define a
waveform in the Music 5000 synthesiser after the note has started playing -
giving another means of getting some expression - though it can be difficult to
handle.
Exclusive MIDI messages
Roger Sapolsky
In a couple of recent contributions to AMPLINEX I have
suggested use of exclusive MIDI messages. However, in a music piece where such
messages are sent simultaneously, or nearly simultaneously, by two or more players,
the MIDI system may not be able to cope. This is likely to be evidenced by a
humming noise, which can only be stopped by switching off the MIDI system.
To avoid this, all exclusive messages included in a program
should be spaced out in time.
Published in AMPLINEX 023, November
1991
