Here is a similar script utilizing Tk and SDL-2.541. There are some glitches, but for the most part it works. See ztk-sound-demo-SDL-new for the sample audio files used in the script.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::Pane;
use SDL;
use SDL::Mixer;
use SDL::Mixer::Channels;
use SDL::Mixer::Samples;

# a demo for using multi channel sound in Tk
# by zentara, utilizing the latest SDL version SDL-2.541 

# make more than the default 2 channels, we make 8, but need 3
printf("We got %d channels!\n", SDL::Mixer::Channels::allocate_channel
+s( 8 ) );

SDL::init(SDL_INIT_AUDIO);
                                                   #mono 1 or stereo 2
SDL::Mixer::open_audio( 44100, SDL::Constants::AUDIO_S16, 1, 4096 );

my $sound1 = SDL::Mixer::Samples::load_WAV('1bb.wav');
my $sound2 = SDL::Mixer::Samples::load_WAV('explosion.wav');
my $sound3 = SDL::Mixer::Samples::load_WAV('cannon.wav');

foreach my $chan(1..3){
   SDL::Mixer::Channels::volume( $chan, 128 ); # set max volume
 }

# setup Tk

$|++;
my $mw = tkinit;
$mw->geometry('900x500+100+100');

$mw->protocol('WM_DELETE_WINDOW' => sub { SDL::Mixer::close_audio(); e
+xit; });

$mw->fontCreate('big', -size=> 16 );


######setup volume indicators#######################
my $chan1_vol = 128; #music
my $chan2_vol = 128; #explosion
my $chan3_vol = 128; #cannon

my $tframe = $mw->Frame(-background =>'black')->pack(-fill=>'x');

$tframe->Label(-background =>'black', -foreground => 'lightyellow',
           -font => 'big', -text => 'Music Vol: ', )->pack(-side=>'lef
+t');
$tframe->Entry(-readonlybackground =>'black', -foreground => 'lightyel
+low',
           -textvariable => \$chan1_vol , -width => 3,
           -font => 'big', -takefocus => 0, -state => 'readonly'
           )->pack(-side=>'left');
$tframe->Label(-background =>'black', -text => ' ',-width=>1, 
               -font => 'big',
               )->pack(-side=>'left');


$tframe->Label(-background =>'black', -foreground => 'lightsteelblue',
           -font => 'big', -text => 'Explosion Vol: ', )->pack(-side=>
+'left');
$tframe->Entry(-readonlybackground =>'black', -foreground => 'lightste
+elblue',
           -font => 'big', -textvariable => \$chan2_vol , -width => 3,
           -takefocus => 0, -state => 'readonly' )->pack(-side=>'left'
+);
$tframe->Label(-background =>'black', -text => ' ', -width=>1,
               -font => 'big', )->pack(-side=>'left');


$tframe->Label(-background =>'black', -foreground => 'lightgreen',
           -font => 'big', -text => 'Cannon Vol: ', )->pack(-side=>'le
+ft');
$tframe->Entry(-readonlybackground =>'black', -foreground => 'lightgre
+en',
           -textvariable => \$chan3_vol , -width => 3,
           -font => 'big', -takefocus => 0, -state => 'readonly')->pac
+k(-side=>'left');
$tframe->Label(-background =>'black', -text => ' ', -width=>1,
               -font => 'big', )->pack(-side=>'left');

my $sound = 1;
$tframe->Checkbutton(
       -text => 'Sound',
       -background => 'lightskyblue',
       -variable => \$sound,
       -command  => \&set_sound,
       -font => 'big')->pack(-side =>'left');

$tframe->Button(-text => 'Exit', 
                -background =>'red',
                -font => 'big',
                -command => sub{ 
                    SDL::Mixer::close_audio();
                    exit; 
                    })->pack(-side=>'right');


#################################################################
my $pane = $mw->Scrolled('Pane', 
             -background =>'black',
             -scrollbars=>'oe', 
         sticky=>'w')->pack(-side => "left", -anchor => "n",
                  -fill=>'both',-expand=>1);

my %keyprs = (
          'm' => {
            text => 'music pause/resume',
                command => \&music_toggle  
         },
          'e' => {
            text => 'explosion',
                 command => sub{ 
                    SDL::Mixer::Channels::play_channel( 2, $sound2, 0 
+); # 1 time
                   }
         }, 

          'c' => {
            text => 'cannon',
                command => sub{ 
                    SDL::Mixer::Channels::play_channel( 3, $sound3, 0 
+); # 1 time
                  } 
        }, 

          'q' => {
            text => 'Exit Program',
        command => sub{ SDL::Mixer::close_audio(); exit; }
        }, 


          'plus' => {
            text => 'Increase Background Music Volume',
                command => sub{ &music_vol(1) }    
        }, 

          'minus' => {
            text => 'Decrease Background Music Volume',
                command => sub{ &music_vol(-1) } 
        }, 

          'F1' => {
            text => 'Increase Explosion Volume',
            command => sub{ 
                     $chan2_vol += 1;
                             if($chan2_vol > 128){$chan2_vol = 128}
                             SDL::Mixer::Channels::volume( 2, $chan2_v
+ol );
                }
        }, 

          'Control-F1' => {
            text => 'Decrease Explosion Volume',
                command => sub{ 
                     $chan2_vol -= 1;
                             if($chan2_vol < 0){$chan2_vol = 0}
                             SDL::Mixer::Channels::volume( 2, $chan2_v
+ol );
                   }
         }, 

          'F2' => {
            text => 'Increase Cannon Volume',
                command => sub{ 
                             $chan3_vol += 1;
                             if($chan3_vol > 128){$chan3_vol = 128}
                             SDL::Mixer::Channels::volume( 3, $chan3_v
+ol );
                   }
         }, 

          'Control-F2' => {
            text => 'Decrease Cannon Volume',
                command => sub{ 
                     $chan3_vol -= 1;
                             if($chan3_vol < 0){$chan3_vol = 0}
                             SDL::Mixer::Channels::volume( 3, $chan3_v
+ol );
                    }
         }, 
    );


#hack to expand pane 
$pane->Label(-text=>'', -font => 'big', -background=>'red',-width =>10
+0)
         ->pack(-fill=>'x',-expand=>1 );


my @order = qw(m e c  plus minus F1 Control-F1 F2 Control-F2 q); 
foreach(@order){ 
$pane->Label(-text => "$_ -> $keyprs{$_}{'text'}",
          -font => 'big',
      -background => 'cyan',
      -anchor => 'w',
      -borderwidth =>2,
      )->pack( -fill =>'x',-expand=>1);

$mw->bind("<$_>", $keyprs{$_}{'command'});

}

# start music
my $music_play = 1;  # to toggle music on/pause
SDL::Mixer::Channels::play_channel( 1, $sound1, -1 ); #continous loop

MainLoop;
############################################
sub music_toggle{ 

    if( $music_play == 0 ){
       SDL::Mixer::Channels::resume(1);
       $music_play = 1;
     }else{
       SDL::Mixer::Channels::pause(1);     
       $music_play = 0;
     }        
}
#############################################
sub music_vol{ 
      $chan1_vol += $_[0];
      if($chan1_vol < 0){$chan1_vol = 0}
      if($chan1_vol > 128){$chan1_vol = 128}
      SDL::Mixer::Channels::volume( 1, $chan1_vol );

}
##########################################
sub set_sound{

 # the -1 setting described in SDL::Mixer::Channels didn't
 # seem to work for non-looping sounds, so I use a volume hack below

  if($sound == 0){
     print "soundoff\n";
      SDL::Mixer::Channels::pause(1);     
      SDL::Mixer::Channels::volume( 2, 0 );
      SDL::Mixer::Channels::volume( 3, 0 );
     return; 
      }
  if($sound == 1){
      print "soundon\n";
      SDL::Mixer::Channels::resume(1);     
      SDL::Mixer::Channels::volume( 2, $chan2_vol );
      SDL::Mixer::Channels::volume( 3, $chan3_vol );
      
      return; 
      }
}
__END__
[download]