Instead of thinking in terms of on-cd size, I would concentrate on determining the total time in seconds and then get the total number of minutes involved. An audio cd can only record a certain number of minutes, (somewhere between 70+ to 84?). I tried getting the metadata and seconds using Audio::Scan and Audio::Wav::Read.

#!/usr/bin/perl -l

use strict;
use Audio::Wav;
use Audio::Scan;
use Data::Dumper::Concise;

my $file = '/root/Desktop/explode.wav';
my $info = Audio::Scan->scan_info( $file );
print Dumper( $info );

my $wav  = new Audio::Wav;
my $read = $wav->read( $file );
my $audio_seconds = $read->length_seconds();
print "Total number of seconds: ", Dumper( $audio_seconds );
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