Audio issues (Denise 2.1)

[hexaae]

My audio cfg:

Audio issues testing Denise 2.1 nightly:

• Samurai Warrior: The Battle of Usagi Yojimbo starts with joint left/right audio, I have to untick the 3rd right channel and tick it again to finally hear expected stereo effect…
• Wizball has some distorted sound with SID filter on (except when using Chamberlin, or adjusting very high/low bias)

Test files: https://gofile.io/d/ODU8qt

[PiCiJi]

Is this a stereo SID game ? or do you want a pseudo stereo effect ? where can i get the game?

is this a general problem ? or game/demo specific ? Was this working in old version 1.3.1 ?

you should use only 1 extra SID in this case. I need to check if there are side effects, if a SID is selected without any channel selected.

haven’t checked WIzball so far, one problem after another. but a BIAS of 0 is not the default Bias. for 8580 = -3000 and 6581 = 500

[hexaae]

No I think is pseudo stereo effect (but I like the spatial depth it adds)… Games are in the Test files link.

Yes general problem (have to untick and tick again right channel on 3rd SID to hear some effects).

Ok, tested with your default BIAS but the issues are still reproducible.

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[PiCiJi]

confirmed. you are right, when untick and tick the channel you hear some extra depth.

This is not a bug, stereo works. It's not so easy to explain. First of all, I wondered why you would choose a pseudo stereo effect (if the program itself only produces mono) do not select the 6581 and 8580 for one channel each. If you select the same SID for both channels, they will produce exactly the same sound. It doesn't matter if it's stereo or mono, because the same thing is generated on both channels. So it's correct that you don't hear a pseudo stereo effect.

I can see your question directly. Why do you get a stereo effect if you briefly deactivate the channel and activate it again? This is because if both channels are inactive, the SID will no longer be emulated. If a channel is ticked again, the SID works again. However, this one no longer has the same internal state as the other SID and thus produces the sound slightly offset. This is because the analog nature of ReSID is emulated and capacitors do not immediately have the charging state like an already running SID. You get the SIDs never synced again. You don't want that at all. However, if the emulator starts with both SID's, they are supplied with data in absolutely the same way.

I could install something that slightly offsets the SID's when rebooting. Cool. in this way you can also achieve a pseudo stereo effect with 2 identical SID models. Normally you take a 6581 on the one and an 8580 to the other channel. Even with different SID's you would hear a better Pseudo Stereo, if I offset the SID's from beginning.

[hexaae]

Thanks for detailed explanation… sounds interesting, I like the pseudo stereo effect after I listened to the Demo “GameOfThrones2SID-GP.d64” (real stereo) :)

[PiCiJi]

An automatic shift of the two SID's for a better pseudo stereo effect is unfortunately not reliably possible, because the SID's have to be active in a certain way.
Analyzing this is unreliable and computationally intensive. As a replacement, I added a hotkey "offset pseudo stereo".
After a short random interval (max 1.5 seconds), this switches a SID off and on again. This can be repeated if the result does not fit.
This saves you from having to manually untick and tick the second channel. Please test the hotkey with the new nightly (is currently being built)

Wizball

I'm having trouble discerning which tone is wrong here. Do you also use the pseudo stereo here? It may be that the wrong sound is caused by an unfortunate pseudo stereo?
Does the problem also occur without pseudo stereo (i.e. with only one active SID)?
Does the problem only occur with the 6581 or also with the 8580 ?
Do I have to do anything specific to hear the sound?

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[hexaae]

Wizball. Never mind: seems reproducible only with my cfg in the first msg. If I set classic config 1 extra SID, default BIAS, and only first one as left or right channel (Default address) sound is ok…

The hotkey idea is a bit awkward IMHO, if it’s impossible a custom option for pseudo stereo I’d remove it altogether (i.e. no hotkey and I would prevent this offset “glitch”, reinitializing all channels on left/right channel changes since it’s a “bug” to remove after all). Maybe in the future you can add a proper extra stereo/reverb effect

[PiCiJi]

What you call a bug is what others call pseudo stereo. Pseudo stereo works because the two SID's are controlled by the CPU in the same way, but do not produce exactly the same thing. Either because one SID is a 6581 and the other is an 8580 or because two 6581s sound different due to analog inaccuracies. The glitch is rather that the effect only occurs with two identical SID's when the channel is switched on/off.
nightly: I removed the hotkey again. There is now an option "intensify Pseudo Stereo" for this.
It is not necessary to disable this option for programs with true stereo, as a pseudo stereo setup is recognized by the fact that another
SID has activated either only the left or right channel and no address range is set for this SID.

Wizball: It’s important that for a “non” stereo game (Pseudo Stereo too) the address range is set to “default“.