
                           BACKTRACK¿ v4.01
                         by Karl Anders ²ygard

           Copyright ½ 1992, Deltaware. All Rights Reserved

This program may be distributed without charge, provided that this text 
file is present and that it and the program files are unmodified.

-- Overview ----------------------------------------------------------

BackTrack¿ is an program that will play any standard >Soundtracker  2.2 
or  Pro/Noisetracker  module  in  the  background  (in  a  multitasking 
fashion). The program may also be run as an accessory.

-- Installation ------------------------------------------------------

BackTrack¿  may  be  installed either as an  accessory  or  a  program, 
depending on the extension of the program name.  If you wish to use  it 
as  an accessory,  rename BackTrack¿ to BACKTRAK.ACC,  place it at  the 
root of your bootdrive and make a reset.  BackTrack¿ will automatically 
appear in the menubar, ready for use.

If  you wish to use BackTrack¿ as a program,  rename  it  BACKTRAK.PRG. 
Running  as a program,  BackTrack¿ is really only useful running  under 
MultiTOS.

-- Usage -------------------------------------------------------------

To load a module and play it,  click 'LOAD' once. The fileselector will 
pop up and you may choose a module. Sufficient memory will be allocated 
and  the module will be loaded.  Unless something goes  wrong,  control 
will  be  returned to BackTrack¿ with the module playing in  the  back-
ground.

To  stop  playing  the module,  click  'KILL'  once.  Playing  will  be 
discontinued and memory is released.

To  pause  and restart sound,  press the 'PAUSE'  and  'PLAY'  buttons, 
respectively.

The  playback frequency can be controlled by clicking the '6.259  kHz', 
'12.517  kHz',  '25.036  kHz' or '50.072 kHz'  buttons.  Upon  clicked, 
playback  will immediately set to the corresponding  frequency.  Higher 
frequency gives better sound,  but requires more processor time.

BackTrack  also  has a Multiplex mode.  This mode implies  some  pretty 
clever cheating, and was first introduced to me by Jarle Kloppbakken of 
Imagina.  It speeds up playback vastly,  but also introduces some  very 
high frequency noise.  In my opinion,  it is really only useful at  the 
50kHz mode. Multiplex mode may be toggled with the 'M/PLEX' button.

On  an unexpanded 8MHz STe, the timings are somewhat like this:

Normal mode:
6.259 kHz - 15%, 12.517 kHz - 30%, 25.036 kHz - 60%, 50.072 kHz - 120%
Multiplex mode:
                 12.517 kHz - 15%, 25.036 kHz - 30%, 50.072 kHz - 60%

Note  the  120%  timing on 50kHz.  Practically  this  means  that  this 
frequency is inconceivable on a unexpanded 8MHz STe.  Only if run on  a 
Mega STe or a TT will this frequency make sense.

When timings exceed 100%,  the computer will skip ticks to prevent  the 
computer  from  crashing.  When a lot of interrupts occur at  the  same 
time,  (i.e. the used moves the mouse manically around the screen etc.) 
the accumulated timings _may_ exceed the magical limit,  and the  sound 
scrapes a bit.  This is especially true when running 25kHz on the  8MHz 
STe.  Selecting a frequency that is too high for your computer does not 
harm anything, but it generally does not sound very nice.

-- Notes on memory management ----------------------------------------

Desk accessories shouldn't allocate memory.  However, I've been naughty 
and not bothered about it.  This trouble is that if you start playing a 
module  inside  a  program,  the memory allocated will  belong  to  the 
program and not the accessory (this is not a bug in  BackTrack,  rather 
than  a "feature" from Atari).  I can't be bothered to get around  this 
right now, so you'll just have to use your brain a little.

I may add that any accessories launched from Chameleon by  K.  Isakovic 
allocates memory that belongs to the desktop.  Thus,  running BackTrack 
from Chameleon fixes the aforementioned problem.

Running  under MultiTOS,  both accessories and program can allocate  as 
much memory as they please. Also, BackTrack supports memory protection, 
and is perfectly well at home in a MultiTOS computer.

-- Requirements ------------------------------------------------------

BackTrack¿  requires  a  DMA soundchip as featured in the  STe  and  TT 
computers.  Thus,  this program will *not* work on an ST.  If there  is 
interest,  I just *might* look into writing a version for the ST. (This 
will most likely not feature the multitasking bit).

Also,  if you would like to use the 50kHz option, you had better have a 
>8MHz STe (Mega STe or TT).

-- Disclaimer --------------------------------------------------------

This program may contain several bugs.  It works nicely for me,  but it 
may  turn *your* STe into a toaster.  Thus I cannot take any  responsi-
bility for any harm done with or by this program.  Use this program  at 
your own risk.

-- Donations? --------------------------------------------------------

This program is shareware.  If you like it,  send some cash or a couple 
of High Quality disks to the author stating so.  All requests cannot be 
answered, but some bribing may help ;^)

-- Buy! Buy! Buy! (Commercial break ;-) ------------------------------

ProTracker ST¿ v2.0 (formerly Esion XLII)

The ultimate music tool. Coming soon.

4 channels with separate volume control and frequency.
Realtime volume and pitch bending
Volume slide/Arpeggio/Vibrato/Portamento
6 - 50 (!) kHz playback frequency (STE)
4 - 50 kHz playback frequency (ST)
64KB sample buffer
Flexible editor with powerful cut and paste operations
 (cut/copy/paste/transpose)
Polyphonic Midi support with realtime recording and touch control
Graphical easy to use sampleeditor
 (cut/copy/paste/reverse/fade/boost/echo/mix)
Powerful sampler option
 (sample/trig/resample/listen, frq. 4-32kHz)
Edit up to 32 songs simultaneously
Runs on any ST, STE, Mega STE and TT using low rez - 320x248 pixels
Intuitive graphical user interface
Compatible with ProTracker Amiga

... and bunches more.

Replay sources included:

 8.2 kHz ST, uses regs. d5-d7/a6, 30% processor time
12.2 kHz ST,  "     "       "   , 50%     "      "
 8.2 kHz ST, vol+pitch, uses regs. d5-d7/a6, 40% processor time
12.2 kHz ST,  "     " ,   "    "       "   , 60%     "       "

12.5 kHz STE, uses no regs., 19% processor time
25.0 kHz STE,   "   "   "  , 38%     "       "
12.5 kHz STE, vol+pitch, uses no regs., 30% processor time
25.0 kHz STE,   "    " ,   "   "   "  , 60%      "      "


----------------------------------------------------------------------
Happy listening,

Mail: Karl Anders ²ygard
      Box 8
      N-6180 S’B²
      Norway

Internet:  Karl A Oygard <karloey@aahs.no>,
           Karl A Oygard <karloey@unix1.mrih.no> or
           "Wizzcat" on the IRC

Phone:     +47 70 40015 (weekends only)

