[hatari-devel] STE sound breakage with lower sound frequencies

[David Savinkoff]

Hi,

Referring to audio.c:

void Audio_SetOutputAudioFreq(int nNewFrequency)
{
	/* Do not reset sound system if nothing has changed! */
	if (nNewFrequency != nAudioFrequency)
	{
		/* Set new frequency */
		nAudioFrequency = nNewFrequency;

		/* Re-open SDL audio interface if necessary: */
		if (bSoundWorking)
		{
			Audio_UnInit();
			Audio_Init();
			DmaSnd_Init_Bass_and_Treble_Tables();
		}
	}
}

It may be better to initialize

DmaSnd_Init_Bass_and_Treble_Tables();

somewhere else because the only function to call

Audio_SetOutputAudioFreq(int nNewFrequency)

is in configuration.c which calls with

Audio_SetOutputAudioFreq(ConfigureParams.Sound.nPlaybackFreq);

THIS is the bad initialization

David

************************

On Feb 13, 2011, Nicolas Pomarède <npomarede at corp.free.fr> wrote: 

Le 13/02/2011 22:57, David Savinkoff a écrit :
> Hi,
>
> Referring to dmaSnd.c:
>
> void DmaSnd_Reset(bool bCold)
> {
> 	nDmaSoundControl = 0;
>
> 	if (bCold)
> 	{
> 		dma.soundMode = 3;
> 		microwire.masterVolume = 7;
> 		microwire.leftVolume = 655;
> 		microwire.rightVolume = 655;
> 		microwire.mixing = 0;
> 		microwire.bass = 6;
> 		microwire.treble = 6;
> 	}
>
> 	/* Initialise microwire LMC1992 IIR filter parameters */
> 	DmaSnd_Init_Bass_and_Treble_Tables();
>
> 	microwire.mwTransferSteps = 0;
> }
>
> DmaSnd_Init_Bass_and_Treble_Tables(); may need to be called
> (for resetting purposes) in a more fundamental place instead of
> DmaSnd_Reset(bool bCold);
>
> This would explain wacky initialization at less than 22050KHz.
>
> David

Yes, I was thinking about that too, it would explain why we can start 
Hatari at 44.1 and switch to 16 kHz and still have sound (but if we 
start directly at 16 kHz, we don't have sound) ; something is not 
correctly initialized.

Nicolas