______________________________   _____      _____   
\_   ___ \______   \_   _____/  /  _  \    /     \  
/    \  \/|       _/|    __)_  /  /_\  \  /  \ /  \ 
\     \___|    |   \|        \/    |    \/    Y    \
 \______  /____|_  /_______  /\____|__  /\____|__  /
        \/       \/        \/         \/    2026 \/ 

              STay4Evr - The SNDH files


Prologue
--------

On a day in autumn 2023, after weeks of experimenting
and enjoying step-by-step successes, a small trick did
change everything. 

Big achievements have already been made. Original 6502
code transformed to 68000 code, pulse width modulation
and even hard sync were possible. Songs for a small demo
screen were ready. Willing to accept compromise, as ring
modulation did not seem possible within reasonable limits,
a small idea turned out to work surprisingly well and 
delivered the last piece of the puzzle. Not perfect, but
with this ring modulation effect "International Karate", 
"Master Of Magic" or "Sanxion" sounded as real as never 
before on an Atari ST. The demo had to be big now.

From day one, Atari chipmusic was about imitating the 
classic C64 musics. Amazing conversions have been made, 
but we never made it this close to the original songs. 
With the demo "STay4Evr", we made our dream come true.    


The Package
-----------

This package contains all songs from our demo "STay4Evr",
which we released in July 2024 at the Sommarhack coding 
convention. It contains two flavors:

- "SID" package: The SID emulated songs, including some 
  additional subsongs which were not used in the demo.

- "YM" package: The songs in YM mode. Unlike in the demo, 
  where this mode was implemented by modifying the pulse
  width, these songs are pure, timerless YM chip musics 
  and they do sound amazingly well and show the real
  greatness of the songs and what they could have been
  on the YM2149 back in the days. 


The SID Emulation
-----------------

The sound emulation for these songs is completely YM-2149 
based, using nothing but modern timer techniques. No DMA 
waveform calculations are used here. This is real chipmusic.

The emulation includes:

- ADSR
- Hard Sync on all waveforms
- Ringmodulation
- Waveforms. Square wave with pulse width modulation, 
  triangle, sawtooth and noise
- Waveform mixing is partly implemented to make volume
  control via mixing possible (Used in Parallax 4 or Ik+)
- High-resolution volume steps for square wave. The 64 steps
  are essential to create a precise linear to log conversion
  of the volumes   
- Filters are obviously not implemented


The music files
---------------

The music files do not contain original C64 code. Basically 
all Hubbard and Daglish songs are running in 68k code,
translated based on the original 6502 code. 

All other songs are streamed SID soundchip data based on an
efficient arj4 packing algorithm.


The Limitations
---------------

At the moment of this release, in our knowledge, the only
proper way to replay these songs might be a real Atari or 
an emulator like Hatari. Music players like Jam for Windows
or Oxygene's SNDH player might struggle with songs using
PWM and high frequencies. We're sure there will be an update
for these players soon.


The Demo
--------

If you still enjoy listening to chipmusic in a demo context 
then feel free to visit our website and find more information
and to download our demo "STay4Evr".

www.creamhq.de