I was making some research on the subject and managed to make a small test program to play ansi music. Still the best solution is to use an old DOS app, in DOSBOX, but for anyone that wants to test it under linux here it is.
Compile it with FreePascal and make sure you have SOX installed on your
system. To install it: sudo apt-get install sox
{
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. xqtr@gmx.com .

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+ --- -- - . - --- --- --- - . - -- --- +

This is a test program to play the old style, ansi music, with the help of
SOX in linux machines. It doesn't work 100% but its too close, cause there
are some undocumented areas in the ansi music format, like the < > chars.
and the Txxx command. Whats the Tempo in ansi music, anyway?

If someone knows more about, let me know. Also... i don't know shit about
music, so the notes maybe different than the original.

The idea is to translate the ANSI music notes, to a SOX frequency that can
play. While playing the music, you will hear a noise from SOX when it
starts and exits. I had the same idea to use SOX, as in this link:
https://stackoverflow.com/questions/13760504/generate-tones-of-specific-
frequency-on-mac-command-line
Which i used to make the Playtone procedure, cause as i said... i ain't
know shit about music.. :)

}

program ansimusic;

uses
crt,
math,
unix,
sysutils;

var
f : text;
b : byte;
c : char;
st : string;

Octave : Byte = 4;
ConstDuration : Real = 0.5;
Duration : Real =0;
LDur : Byte;

Function Real2Str (R : Real; D:Byte) : String;
Var S : String;
begin
Str (R:10:d,S);

Real2Str:=S;
end;

procedure playtone(n:string; dur:real; oct:byte);
const
temp = 1.0594630943592952646;
A4 = 440;
var
note_int:byte;
A0 : Real;
C0 : Real;
HZ : Real;
i:byte;
begin
for i:=1 to Length(n) Do
n[i]:=Upcase(n[i]);
case n of
'A' : note_int:=10;
'A#' : note_int:=11;
'A-' : note_int:=9;
'B' : note_int:=12;
'B#' : note_int:=13;
'B-' : note_int:=11;
'C' : note_int:=0;
'C#' : note_int:=1;
'C-' : note_int:=13;
'D' : note_int:=2;
'D#' : note_int:=3;
'D-' : note_int:=1;
'E' : note_int:=4;
'E#' : note_int:=5;
'E-' : note_int:=3;
'F' : note_int:=6;
'F#' : note_int:=7;
'F-' : note_int:=5;
'G' : note_int:=8;
'G#' : note_int:=9;
'G-' : note_int:=7;
end;
A0 := A4 / 16;
C0 := A0 * ( 1 / temp)**9;
HZ := C0*Power(2,oct+1) * Power(temp,note_int);
//HZ:=$( bc -l <<< "$C0_HZ * 2^$OCTAVE * $EQL_TEMPERAMENT ^ $NOTE_INT" )
fpsystem('play -n synth '+Real2Str(dur,8)+' sin '+Real2Str(hz,8)+' 2>/dev/nul ');
end;

Procedure ProcessMusic(Music:string);
Var
snum:string;
Count:Word;
TCount:Word;
Note:String;
Begin
Count:=1;
While Count <= Length(Music) Do Begin

if keypressed then begin
halt;
end;


Write(Music[Count]);
if (Music[Count]=#27) and (Music[Count+1]='F') Then Count:=Count+2;
Case Music[Count] Of
#27 : Count:=Count+1;
'[' : Count:=Count+1;
'L' : Begin
TCount:=Count+1;
SNum:='';
While (Music[TCount] in ['0'..'9']) and (TCount<=Length(Music)) D
Begin
snum:=snum+Music[TCount];
TCount:=TCount+1;
End;
If snum='' Then LDur:=1 Else Begin
Count:=TCount;
LDur := StrToInt(snum);
Duration := ConstDuration / LDur;
End;
End;
'T' : Begin
TCount:=Count+1;
SNum:='';
While (Music[TCount] in ['0'..'9']) and (TCount<=Length(Music)) D
Begin
snum:=snum+Music[TCount];
TCount:=TCount+1;
End;
If snum='' Then LDur:=1 Else Begin
Count:=TCount;
LDur := StrToInt(snum);
Duration := ConstDuration / LDur;
End;
End;
'O' : Begin
Count:=Count+1;
Octave:=StrToInt(Music[Count]);
//Count:=Count+1;
End;
'M' : bEGIN
Count:=Count+1;
Case Music[Count+1] Of
'L' : Begin
LDur:=1;
Duration := ConstDuration / LDur;
End;
'F' : ;
'B' : ;
'N' : Duration := (ConstDuration / LDur) * (7/8);
'S' : Duration := (ConstDuration / LDur) * (3/4);
End;

Count:=Count+1;
End;
'P' : Begin
TCount:=Count+1;
SNum:='';
While (Music[TCount] in ['0'..'9']) and (TCount<=Length(Music)) D
Begin
snum:=snum+Music[TCount];
TCount:=TCount+1;
End;
Count:=TCount-1;
Duration := ConstDuration / StrToInt(snum);
Delay(Trunc(Duration));
End;
'N' : Begin
Duration := (ConstDuration / LDur) * (7/8);
COunt:=COunt+1;
End;
'S' : Begin
Duration := (ConstDuration / LDur) * (3/4);
COunt:=COunt+1;
End;
'A'..'G'
: Begin
Note:=Music[Count];
If Count+1<=Length(Music) Then Begin
if Music[Count+1] in ['#','+','-','.'] Then
Case Music[Count+1] Of
'+' : Begin
Note:=Note+'#';
COunt:=COunt+1;
PlayTone(Note,Duration,Octave);
End;
'#' : Begin
Note:=Note+'#';
COunt:=COunt+1;
PlayTone(Note,Duration,Octave);
End;
'-' : Begin
Note:=Note+'-';
COunt:=COunt+1;
PlayTone(Note,Duration,Octave);
End;
'.' : Begin
COunt:=COunt+1;
PlayTone(Note,Duration+(Duration/2),Octave);
End;
End
else PlayTone(Note,Duration+(Duration/2),Octave);

End;
COunt:=COunt+1;
End;
Else
Count:=Count+1;
End;



End;
End;

procedure demo;
begin
ProcessMusic('MFT225O3L8GL8GL8GL2E-P8L8FL8FL8FML2DL2DP8');
ProcessMusic('MFO3L8GL8GL8GL8E-L8A-L8A-L8A-L8GO4L8E-L8E-L8E-MLL2C');
ProcessMusic('MFL8CMNO3L8GL8GL8GL8DL8A-L8A-L8A-L8GO4L8FL8FL8FMLL2DL2DMN');
ProcessMusic('MFO4L8GL8GL8FL8E-O3L8E-L8E-L8FL8GO4L8GL8GL8FL8E-O3L8E-L8E-');
ProcessMusic('MFL8FL8GO4L8GL8GL8FL8E-P4L8CP4L1GO3L8A-L8A-L8A-MLL2FL2FMN');
ProcessMusic('MFP8O3L8A-L8A-L8A-L8FL8DL8DL8DO2L8BL8A-L8A-L8A-L8GO1L8GL8');
ProcessMusic('MFGL8GL8CO3L8A-L8A-L8A-L8FL8DL8DL8DO2L8B-L8A-L8A-L8A-L8GO1');
ProcessMusic('MFL8GL8GL8GL8CO3L8GO4L8CL8CL2CO3L8BL8BL8BO4L8DL2DL8DL8DL8D');
ProcessMusic('MFL8E-L8E-L8DL8DL8FL8FL8EL8E-L8GT50O4L8GL8FL8FL8A-L8A-L8G');
ProcessMusic('MFL8GL8B-L8B-L8A-L8A-L8CL8CL8BL8B-L8DL8CL8E-L8E-L8E-L8CL8');
ProcessMusic('MFGL8GL8GL8E-L8CO3L8GL8GL8E-L8CL8CL8CO2L8B-O4L8FL8E-L8E-L8');
ProcessMusic('MFBL8GL8FL8FL8DO3L8BL8GL8FL8DO2L8BO3L8CL8CL8CO4L8E-L8E-'); end;

begin
if (paramstr(1)='DEMO') or (paramstr(1)='demo') then begin
demo;
exit;
end;
if not fileexists(paramstr(1)) then begin
writeln;
writeln('File doesn''t exist. Aborting...');
writeln('execute like this to hear a demo:');
writeln('#> ./ansimus demo');
writeln;
exit;
end;
writeln('Get more songs here: http://artscene.textfiles.com/ansimusic/songs/' ;
writeln('Press key to abort...');
assign(f,paramstr(1));
reset(f);
While not eof(f) do begin
readln(f,st);
if st[1]=#27 then processmusic(st);
writeln;
end;
close(f);
end.

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