Reduce default sample rate and chunk size

CHANGELOG.md

@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improved layout of 4-line HD44780 LCD.
   * MT-32 status line moved to bottom row.
   * Part levels now 3 rows high.
+- Default sample rate and chunk size reduced to 48000Hz and 256 samples.
 
 ### Fixed
 

include/config.def

@@ -27,8 +27,8 @@ END_SECTION
 
 BEGIN_SECTION(audio)
 CFG(output_device,			TAudioOutputDevice,			AudioOutputDevice,			TAudioOutputDevice::PWM					)
-CFG(sample_rate,			int,						AudioSampleRate,			96000									)
-CFG(chunk_size,				int,						AudioChunkSize,				512										)
+CFG(sample_rate,			int,						AudioSampleRate,			48000									)
+CFG(chunk_size,				int,						AudioChunkSize,				256										)
 CFG(i2c_dac_address,		int,						AudioI2CDACAddress,			0x4c,							true	)
 CFG(i2c_dac_init,			TAudioI2CDACInit,			AudioI2CDACInit,			TAudioI2CDACInit::None					)
 END_SECTION

sdcard/mt32-pi.cfg

@@ -104,8 +104,8 @@ output_device = pwm
 #
 # FluidSynth renders at this sample rate directly.
 #
-# Values: 32000-192000 (96000*)
-sample_rate = 96000
+# Values: 32000-192000 (48000*)
+sample_rate = 48000
 
 # Set audio rendering chunk size (samples).
 #
@@ -115,14 +115,14 @@ sample_rate = 96000
 # cause underruns (distortion artifacts).
 #
 # Latency is a function of chunk size and sample rate, for example:
-# 512 samples / 2 channels / 96000Hz * 1000ms = 2.67ms of latency.
+# 256 samples / 2 channels / 48000Hz * 1000ms = 2.67ms of latency.
 # See documentation for recommended values for various Raspberry Pi models.
 #
 # The minimum value varies depending on audio output device.
 # For PWM, the minimum is 2, for I2S the minimum is 32.
 #
-# Values: 2-2048 (512*)
-chunk_size = 512
+# Values: 2-2048 (256*)
+chunk_size = 256
 
 # Set address (hexadecimal) of I2C DAC control interface.
 #