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The Datafile PD-CD 1 Issue 2
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PDCD-1 - Issue 02.iso
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_utilities
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utilities
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004
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_effex
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!Effex
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UserGuide
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1993-04-08
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ü ëDocumentation for !Effex
Ç Effex written by and copyright Paul Mason
Like most computers nowadays (with the exception of the PC),
Acorn machines have the ability to play high quality sound. This
is achieved by literally controlling the speaker. A sample is
basically raw data describing the various positions of the
speaker. By such low-level control as this, it is possible to
create very nearly any sound. Such samples are obtainable from
several different sources. Many good sounds can be found on PD
discs, and Amiga/ST PD has a wealth of samples. Alternatively, if
you have access to a sampler, almost any sound can be captured
and saved onto disc. The other main option is to calculate your
sample, using mathematics or one of the good commercial programs.
Whichever way you obtain your sample, you will need to play it
back and if you are more adventurous, manipulate it.
Effex is a versatile sample editor. It allows fully controllable
editing of the sample - cutting and pasting, mixing, and a whole
host of other special effects that you can use to add a little
something to the sound.
üThe main windowÇ
When you load a sample into Effex, by either double-clicking on
its icon, or dragging it to the Effex icon, the main window
will open, with a view of the sample at the bottom. On the far
right of the window, just above the sample viewer, you will find
a zoomer box. This operates in the standard way - like the one on
!Draw or !Paint. Note that it is not possible to have the zoom
set to less than 1 (ie. the right number larger than the left).
If you zoom in on the sample, you can move about inside it by
dragging the scroll bar at the bottom.
üSelections and the caretÇ
In order to edit the sample, you should first know how to select
an area, and move the caret. The selection defines what is going
to be acted on, and the caret specifies where any destination
data (eg. a move or copy) will go.
To select an area, click (select) where you want the start to be,
and drag the pointer to where you wish to end the selection. To
change a selection, click (select) on the end you wish to change
and drag. If you click (select) inside the sample view, the
nearest end of the selection will jump to where you clicked.
To clear the selection, click (menu) over the window, and choose
'Clear selection' off the selection submenu. Alternatively, press
CTRL Z.
To select the entire sample, choose 'Select all', or press
CTRL A.
When you make a selection, the icons either side of 'Sel' on the
main window will change to reflect the position within the sample
Çof you selection. The left icon is the start, the right is the
end. You can enter values into these to change the selection.
To zoom the selection so as it fits the entire window (if
possible), press Z or choose Zoom from the Selection submenu.
To move the caret, simply click (adjust) in the view, and a red
line will appear, marking the caret position. Again, the icon by
the word 'caret' will change to reflect the caret position. You
can enter a value into here also. Alternatively, click on the up
or down arrows to move the caret (very slightly). Pressing shift
while clicking on these will step the caret by 16. (Note that
shift has that effect on any up/down arrows - the value in
question steps by 16).
Full details about the sample, selection and caret positions can
be obtained from the Sample window in the Misc submenu.
üOperating on a selectionÇ
All menu selections described in this section are made from the
Selection submenu unless otherwise stated.
Once you have made a selection, you may wish to move, delete or
copy it.
Deleting a selection can be achieved by choosing Delete, or
pressing CTRL X.
Moving a selection to the caret position can be done by choosing
Move or pressing CTRL V.
Copying can be done with two effects. To copy the block,
inserting it at the caret position, choose copy, or CTRL C. To
copy it, overwriting data at the caret position, choose copy
over, or CTRL Y.
Mixing enables you to overlay parts of the sample. If, for
example, you have in your sample, a sound of a motorbike, and
later on, a sound of a scream, they can be mixed together, to
produce the sound of a motorbike while someone is screaming. To
mix the selection with data after the caret, choose Mix. To mix
data directly before the start of the selection, choose pre-mix.
To mix after the end of the selection, choose post-mix.
üPlaying the sampleÇ
In order to play the sample, bring up the menu, and choose Play
from the Playing submenu. Alternatively, press CTRL P. If the
sample plays too fast or slow, change the sample rate. This can
be done by altering the value by the word KHz, or the value by
the word î╡sÇ. If you increase the KHz value, the sample will speed
up (on replaying). The ╡s value is inversely proportional, ie.
increasing it will slow down the sample.
To alter the volume, click on the up/down arrows above and below
the value 127. Alternatively, enter a new value. If you cannot
hear any sound, the speaker is either off, or the master volume
Çlevel is too low. Press F12 and type :
*Speaker On
*Volume 127
To stop playback of a sample, choose Stop from the Playing
submenu, or press CTRL S. During playback it is possible to alter
the volume (as normal), and also 'bend' the pitch. The latter is
achieved by clicking on the Pup and Pdown icons, or choosing
Pitch up or down from the playing submenu. Maximum volume can
instantly be set by choosing Max. volume or pressing CTRL L.
If you wish to see what part of the sample is being played,
choose Play tracking or press CTRL T. This will then move the
caret in sync with the sample. Clicking (adjust) anywhere in the
viewer while play tracking will play from that position. Once the
sample has stopped, you can move the caret anywhere and press
space or choose Continue, and playing will start from the caret.
Note that if you have finished playing a selection, the play
cannot be resumed with the caret after the end of the selection.
To playback the selection, choose Play from the selection
submenu, or press CTRL E.
üSample typesÇ
At present, Effex supports logarithmic, signed linear and
unsigned linear samples, and can play all of these. The following
file formats are interpreted by Effex :
LogSampl (&631) : loading this forces the sample type to Log
SgnSampl (&632) : loading this forces the sample type to Signed
UnsSampl (&633) : loading this forces the sample type to Unsigned
Effex (&634) : the format when saved is restored, as is the
selection and caret details, and sample rate.
Armadeus (&D3C) : sample type is set to unsigned, and sample rate
is restored.
Any other file type defaults to unsigned.
The sample type can be changed by choosing the appropriate type
from the Misc submenu.
To convert from a Log sample to Signed linear, choose Log2Lin
To convert vice versa, choose Lin2Log
To change from Signed to Unsigned, choose (Un)Sign.
üEffectsÇ
All menu selections described here are made from the Effects
submenu unless otherwise stated.
If you wish to add a special effect to your marked selection
only, ensure the 'Selection' option (at the top) is ticked.
Otherwise, the effect will be enforced on the whole sample.
Ç
Reverse : reverses (flips) the chosen area
Silence : amplifies the chosen area by 0
Fade in (CTRL I) : fades the area in from quiet to full volume
Fade out (CTRL O) : fades the area out from full to quiet
Amplify : amplifies the area by the given percentage
Quieten : amplifies the area by (10000/value) percentage
ie. Quietening by 200% will counteract an amplification of 200%
Eor : eors each byte of the area with the given value
Add : adds the given value to each byte of the area (moves the
sample up or down)
High-Amp filter : clips any values that exceed the given value
Low-Amp filter : clips any value that fall below the value
Core filter : See below
LowFreq boost : Boosts low frequencies and volumes
HighFreq boost : Boots high frequencies and volumes
Modulation and Echo : see below
üFilters
ÇHA : if a + precedes the value, the centre (normally 128) is
added to the value before clipping
LA : is a - precedes it, it is subtracted from the centre
Core filter : if any value falls within the given value either
side of the centre, it is rounded off to the centre value. If
used carefully (and subtley), this filter can remove noise from a
sample, without affecting the quality too seriously.
üModulationÇ
To modulate the sample, enter a formula into one of the five
spaces (the top may contain a two-way scrambling formula). The
following variables are guaranteed to be defined :
X = x position within sample
Y = value
Z = previous value
The formula should output a new value for Y, ie. for every byte,
X,Y and Z are set up, and the formula is called, storing the
result back in the sample.
Please note that modulation is very SLOW!
üEchoÇ
Three different echoes are provided to enhance your sample. By
changing the echo length, different 'depths' of echo can be
obtained. The echo strength will affect how powerful the echo is.
Echo strengths above 100% are not recommended.
Echo (or pressing E) is the softest echo
ÇFlange echo (F) produces are hard, metallic echo
Hall echo (H) produces a complex echo
A pipe-effect echo can be achieved by a strong hall echo (80%)
with length 64 or thereabouts, and then repeated LF boosts of
about 2-8. LF boosts often have the effect of smoothing an echo
(or any sound).
üSaving the sampleÇ
To save the sample, open the Save submenu. From this, upto three
save windows can be opened. Saving from the Log submenu can only
be achieved when the sample is logarithmic. It will settype its
file to LogSampl (&631). The Unsigned and signed submenus operate
in a similar way, but saving as unsigned or signed files.
Saving from the Effex submenu can be achieved at any time. As
well as saving the sample, it will store details about sample
rate, selections and caret position. It also stores the sample
rate.
Saving as an Armadeus file is only possible with an unsigned
sample, and saves the sample rate along with the sample.
üProgramming techniques
ÇThe Wimp front end for Effex is written entirely in BASIC, using
machine code only for the movement and special effects (except
modulation) routines. This means that Effex is easily customable
for an experienced programmer. This does however have the slight
drawback of slow redraws (even this isn't too noticeable on an
Arm3). The menu structure is such that extra options can be added
later - indeed, I would be interested in improvements/additions
made to Effex.
üKnown problemsÇ
Effex has several known problems which will hopefully be removed
in a future version.
Saving to !Edit is only possible if you first open a window and
then drag the icon into that.
In high magnification, the selection may not always be displayed
properly.
Due to the way 256-colour modes organise their palette, the
selection may not be displayed at all in such modes.
It is only possible to zoom in on the selection when in 1:1 zoom.
