$VER: cha_echo.readme 1.4 (2000.02.26) © Claude Heiland-Allen

BUGFIX: could divide by 0 if instrument default pitch >= C-4


A better echo effect for processing samples using OctaMED
SoundStudio with the nsm patch system.


Features:
 -  reasonably fast
 -  sounds good (much better than OSS)
 -  easy to use command line interface
 -  parameters use standard units (eg. seconds instead of a
    number of samples)
 -  feedback means echoes die away naturally (not just a
    fixed number of repeats)
 -  highly modular object oriented design allows code to be
    shared between plugins (see mus/edit/cha_source.lha)


Usage:
    cha_echo FROM/A,TO/A,DELAY/K,DECAY/K,REVERB/K,
             FREQ=FREQUENCY,RATE/K,VOLUME/K
 -  FROM    source sample number (OSS style, 1 .. 1V)
 -  TO      destination sample number (can be same as FROM)
            (if the output space is too short then the size
            of the sample is increased automatically)
 -  DELAY   the delay time between echoes in seconds
 -  DECAY   the decay factor between echoes (-1 .. 1)
 -  REVERB  the reverberation time in seconds (time until
            the sound has decayed by -60 dB)
 -  FREQUENCY
            instead of delay, a frequency can be used (one
            less calculation for you to do yourself)
 -  RATE    the sampling rate (default to the default pitch
            of the source sample, or C-3 (16574 Hz) if that
            instrument has no default pitch)
 -  VOLUME  the volume factor for the output (default 1),
            use values < 1 if you get distortion (usually
            with high decay / reverb values)
 -  exactly two of DELAY, DECAY, REVERB, and FREQUENCY must
    be specified, but it is useless to specify DELAY and
    FREQUENCY together as these control the same aspect of
    the echo


Examples:
 -  cha_echo 1 2 delay 0.2 decay 0.333
        fairly average echo, enough to be noticeable
 -  cha_echo 1 2 freq 200 reverb 0.25 rate 22050
        very short echoes sound strange :)


Bugs:
 -  due to the 32 bit floats used internally, accuracy
    may waver when using extreme values of REVERB
 -  the routine to add space to the destination tends to
    add too much space
 -  the error messages aren't very informative


Tips:
 -  control-C interrupts processing, for emergencies
 -  centralize the sample before echoing, otherwise the
    offset error increases


Future:
 -  cha_autoecho: using the current tempo, echo with delay
    set in terms of a number of lines (that will probably
    be a separate program that controls this one)


Claude

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                24152   24152 100.0% -lh0- f4e4 Feb 26  2000 cha_echo/cha_echo
[generic]                 2835    2835 100.0% -lh0- 846b Feb 26  2000 cha_echo/cha_echo.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         2 files   26987   26987 100.0%            Feb 26  2000