Change the default resampler to Cubic Spline

The gaussian resampler has too much high-frequency attenuation for many sounds,
particularly with lower sample rates or pitches. A gaussian resampler is still
used for the Chorus effect, which is expected to have frequency upswings where
supressing aliasing distortion is useful, and the late reverb feedback tap
where modulation creates a Chorus effect and high-frequency dampening typically
occurs anyway.

core/voice.h

@@ -280,6 +280,6 @@ struct SIMDALIGN Voice {
     static void InitMixer(std::optional<std::string> resopt);
 };
 
-inline Resampler ResamplerDefault{Resampler::Gaussian};
+inline Resampler ResamplerDefault{Resampler::Spline};
 
 #endif /* CORE_VOICE_H */

utils/alsoft-config/mainwindow.cpp

@@ -114,8 +114,8 @@ constexpr std::array resamplerList{
     NameValuePair{ "Point", "point" },
     NameValuePair{ "Linear", "linear" },
     NameValuePair{ "Cubic Spline", "spline" },
+    NameValuePair{ "Default (Cubic Spline)", "" },
     NameValuePair{ "4-point Gaussian", "gaussian" },
-    NameValuePair{ "Default (4-point Gaussian)", "" },
     NameValuePair{ "11th order Sinc (fast)", "fast_bsinc12" },
     NameValuePair{ "11th order Sinc", "bsinc12" },
     NameValuePair{ "23rd order Sinc (fast)", "fast_bsinc24" },
@@ -147,6 +147,16 @@ constexpr std::array hrtfModeList{
     NameValuePair{ "Full", "full" },
 };
 
+constexpr auto GetDefaultIndex(const al::span<const NameValuePair> list) -> size_t
+{
+    for(size_t i{0};i < list.size();++i)
+    {
+        if(!list[i].value[0])
+            return i;
+    }
+    throw std::runtime_error{"Failed to find default entry"};
+}
+
 #ifdef Q_OS_WIN32
 struct CoTaskMemDeleter {
     void operator()(void *buffer) { CoTaskMemFree(buffer); }
@@ -668,9 +678,10 @@ void MainWindow::loadConfig(const QString &fname)
     ui->srcSendLineEdit->clear();
     ui->srcSendLineEdit->insert(settings.value(QStringLiteral("sends")).toString());
 
-    QString resampler = settings.value(QStringLiteral("resampler")).toString().trimmed();
-    ui->resamplerSlider->setValue(2);
-    ui->resamplerLabel->setText(std::data(resamplerList[2].name));
+    auto resampler = settings.value(QStringLiteral("resampler")).toString().trimmed();
+    static constexpr auto defaultResamplerIndex = GetDefaultIndex(resamplerList);
+    ui->resamplerSlider->setValue(defaultResamplerIndex);
+    ui->resamplerLabel->setText(std::data(resamplerList[defaultResamplerIndex].name));
     /* "Cubic" is an alias for the 4-point spline resampler. The "sinc4" and
      * "sinc8" resamplers are unsupported, use "gaussian" as a fallback.
      */
@@ -769,9 +780,10 @@ void MainWindow::loadConfig(const QString &fname)
     ui->enableSSE41CheckBox->setChecked(!disabledCpuExts.contains(QStringLiteral("sse4.1"), Qt::CaseInsensitive));
     ui->enableNeonCheckBox->setChecked(!disabledCpuExts.contains(QStringLiteral("neon"), Qt::CaseInsensitive));
 
-    QString hrtfmode{settings.value(QStringLiteral("hrtf-mode")).toString().trimmed()};
-    ui->hrtfmodeSlider->setValue(2);
-    ui->hrtfmodeLabel->setText(std::data(hrtfModeList[3].name));
+    auto hrtfmode = settings.value(QStringLiteral("hrtf-mode")).toString().trimmed();
+    static constexpr auto defaultHrtfModeIndex = GetDefaultIndex(hrtfModeList);
+    ui->hrtfmodeSlider->setValue(defaultHrtfModeIndex);
+    ui->hrtfmodeLabel->setText(std::data(hrtfModeList[defaultHrtfModeIndex].name));
     /* The "basic" mode name is no longer supported. Use "ambi2" instead. */
     if(hrtfmode == QLatin1String{"basic"})
         hrtfmode = QStringLiteral("ambi2");