Explicitly set default normalisation threshold for librespot

The normalisation threshold should be in ratio space, but the default
value is specified in dB space, so using it as the default implicitly
without passing it through the db_to_ratio function causes distortion
and clipping when normalisation is enabled.

src/spotify.rs

@@ -4,6 +4,7 @@ use librespot_core::config::SessionConfig;
 use librespot_core::session::Session;
 use librespot_core::session::SessionError;
 use librespot_playback::config::PlayerConfig;
+use librespot_playback::player::NormalisationData;
 use log::{debug, error, info};
 
 use librespot_playback::audio_backend;
@@ -190,6 +191,9 @@ impl Spotify {
             bitrate: bitrate.unwrap_or(Bitrate::Bitrate320),
             normalisation: cfg.values().volnorm.unwrap_or(false),
             normalisation_pregain: cfg.values().volnorm_pregain.unwrap_or(0.0),
+            normalisation_threshold: NormalisationData::db_to_ratio(
+                PlayerConfig::default().normalisation_threshold,
+            ),
             ..Default::default()
         };