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Sound Chip?

Posted: Wed Jun 02, 2021 4:44 am
by Travis Bryant moore

How does the Chickenlips X16 sound chip or chips compare to the armsid chip? And which one is best? I mean I think the intent was many more voices for the sid but was cut short due to time constants. So sound wise I am not requesting any changes but just counting the voices and how sound is done between the sids and sound done differently on the x16. 


Sound Chip?

Posted: Wed Jun 02, 2021 11:20 am
by kliepatsch

Yes I think the idea was to have a bigger version of the SID. But the Vera's PSG and the SID differ in a few aspects:

Obviously count of voices. The SID has 3, the PSG has 16.

Volume control: the SID has analog ADSR envelopes. They sound nice and smooth, however, they aren't very flexible. The maximum volume cannot be changed. The PSG is more flexible: you can simply set a number as the voice's volume. This flexibility comes at the cost that the volume has to be updated manually. And the volume control is kinda coarse, so sometimes you can hear when the volume is updated to an adjacent level.

These were the two points where the PSG beats the SID. The other points all go to the SID. It has analog sound generation, while the PSG is fully digital. The difference becomes noticeable at high pitched sounds, where the PSG output can start to sound really unpleasant due to aliasing. The PSG also has no ring modulation, and, most importantly, NO FILTER. 

I think those are the most important points. But let's not forget that the X16 also comes with an FM chip, which nicely complements the PSG, and you cannot really compare it to the SID.


Sound Chip?

Posted: Wed Jun 02, 2021 4:09 pm
by ZeroByte

Kliepatsch's Concerto demo shows you what kind of goodness can be made with the simple PSG functionality. What it loses in "features-per-voice" are made up by the sheer number of channels. If you bolt on a lot of your own modulations, such as PWM, or ADSR, then you can make the same kinds of sounds with the PSG as you could with the SID, with the exception of the filters and ring modulator. At its core, it's the same thing - 4 digital waveforms at selectable pitches. Also, the PSG can't key multiple waveforms on the same voice at the same time like SID can. But since there're 16 voices, the VERA PSG can actually generate MORE kinds of sounds than SID can in that regard, even if triggering all 4 waveforms simultaneously on one voice were possible.

 


Sound Chip?

Posted: Wed Jun 02, 2021 9:54 pm
by rje

To pile on:  a few folks here have written assembly that uses the PSG, and programmatically manage ADSR-like envelopes.  It's only a matter of time before someone generalizes that code into an envelope controller thing or something.

For the kind of stuff I used to do on the C64, that's sufficient.


Sound Chip?

Posted: Thu Jun 03, 2021 1:21 am
by Travis Bryant moore

Can the FM chip do real sound or music or movie audio? Such as casset like audio or cd in an analog channel?


Sound Chip?

Posted: Thu Jun 03, 2021 1:39 am
by Elektron72


13 minutes ago, Travis Bryant moore said:




Can the FM chip do real sound or music or movie audio? Such as casset like audio or cd in an analog channel?



The YM2151 FM synthesis chip cannot play audio samples. However, the VERA's PCM playback system can.


Sound Chip?

Posted: Thu Jun 03, 2021 1:43 am
by Travis Bryant moore


2 minutes ago, Elektron72 said:




The YM2151 FM synthesis chip cannot play audio samples. However, the VERA's PCM playback system can.



That is really good then.


Sound Chip?

Posted: Thu Jun 03, 2021 3:26 am
by BruceMcF


2 hours ago, Travis Bryant moore said:




Can the FM chip do real sound or music or movie audio? Such as casset like audio or cd in an analog channel?



No, it's a frequency modulation synthesizer chip. So if there is an FM keyboard in the movie audio track, it can play the FM keyboard part. Not quite Beverly Hills Cop (that's a different FM chip), but the same idea. It's the chip in the Yamaha DX27, so if you search Youtube for DX27 patches, you can hear some of what it can do. Also, it was used in some arcade systems in the 80s.


Sound Chip?

Posted: Thu Jun 03, 2021 4:15 am
by Travis Bryant moore

Was there a way to digitize auto and store it in a digital memory and convert back into analog sound? Say I ran a cd or 8 track into an analog to digital converter and stored it on a sd card and played it back though a digital to analog converter and maybe had the help with an amplifier? Or would such sounds be run by a Yamaha dx27? Old 8 track players had a pre amp and op amp and I think about 4 channels on the head reader not that matters other than it stored music on 4 channels on a single magnetic tape. And could the DX24 play one audio channel or more than one like a voice but dymanically shift the voice to emulate an audio channel?


Sound Chip?

Posted: Thu Jun 03, 2021 6:16 am
by TomXP411


1 hour ago, Travis Bryant moore said:




Was there a way to digitize auto and store it in a digital memory and convert back into analog sound? Say I ran a cd or 8 track into an analog to digital converter and stored it on a sd card and played it back though a digital to analog converter and maybe had the help with an amplifier? Or would such sounds be run by a Yamaha dx27? Old 8 track players had a pre amp and op amp and I think about 4 channels on the head reader not that matters other than it stored music on 4 channels on a single magnetic tape. And could the DX24 play one audio channel or more than one like a voice but dymanically shift the voice to emulate an audio channel?



If I recall, there is a PCM playback channel in VERA. 

As to the DX7, that's an FM synthesizer, and it uses a similar chip as the Commander X16's YM2151. 

Most of this is covered in the FAQ, which is linked at the top of this page (although @Perifractic, the FAQ may need updating to cover the PSG.)

As to whether the CX16 compares to SID chips... I may be the only one who will say this, but I think the Yamaha FM synth blows away the SID in terms of sound quality, and if you add the PSG on top of that, there's simply no contest. The only Commodore sound system that can come close would be an Ultimate 64 with an FM cartridge installed.