Is the POKEY chip so much better than the TIA?

[Mister-VCS]

We all know that POKEY is no SID (C64), but comparing my (small) XL library with the VCS-one I can't find a game with

(much) better music and sound than some later 2600 games (for example: Pole Position, Crystal Castles, Pressure Cooker, Ghostbusters, Pitfall II...)

 

My 600XL cartridges are:

 

Blue Max (with 1064)

Pac-Man

Joust

Robotron: 2084

Pengo

Donkey Kong

Donkey Kong Jr.

River Raid

Carnival Massacre

Pole Position

Moon Patrol

 

opinions?

[Marius]

It's not the fault of the pokey chips that the tunes in those games do sound so mediocre. The pokey chip is amazing (well that is an opinion... my opinion) and I would never trade it with a SID (although I like the SID too... I like the pokey sound better).

 

You really should listen to some great chiptunes for pokey. Stereo it is even cooler.

 

Don't rely on (atari) games to get fabulous music.

[+FujiSkunk]

Pitfall II doesn't count because it didn't use the TIA for its music.

 

The POKEY is technically better than the TIA in just about every way. The TIA has some interesting settings that lead to some neat sound effects the POKEY can't create, but as far as music goes, there is no comparison. The TIA has two channels and 32 different pitches, not all of which line up to "real" musical notes. Actually that's not entirely true. Each tone the TIA can generate has 32 different pitches, but those pitches are usually not the same as for any other tone. With some careful composition and crafty bit work, you can make decent sounding music, but it takes some effort. Compare this to the POKEY, which has four channels with 256 different pitches. You can even go a step further and combine pairs of channels to create one or two channels with 16-bit tuning. That's 65,536 different pitches across more-or-less the same range as the POKEY with 8-bit tuning or the TIA with 5-bit tuning. Much easier to create music with.

[Rybags]

One thing they screwed up with Pokey is the LFSR sampling for non-pure AUDC types. It's just point sampled in time so the output sequence will often be different for each given AUDF value and even different for the same value dependant on when a sound starts where with TIA the sampling is consistent regardless of AUDF which makes those sounds more regular and predictable.

 

But really, TIA doesn't have a chance. Pokey is an evolution of it, and 32 distinct frequencies loses out enormously even to just 256 per voice, and only 2 voices loses out to 4.

[+phoenixdownita]

Pitfall II doesn't count because it didn't use the TIA for its music.

...

Not 100% correct I think.

The 2600 cart pinout has no place for an external audio (the way the 7800 does), the way I understand the DPC to work is that you can read a particular register that holds the amplitude of the multi wave generation that happens within the DPC and then send that to the 2600 sound register (which is the TIA).

 

So although the TIA does not generate the actual notes I believe it does play them, while the DPC is the generator and via HINT one can build the datapump, which is what Pitfall II does if I am reading the specs right.

 

Feel free to correct me if I am wrong.

[toiletunes]

Listen to Beef Drop on a 7800 with and without Pokey. The TIA version does the job, but Pokey blows it away.

[Rybags]

Both chips allow "forced volume" which is another way of saying sample playback.

 

It generally takes lots of processing because not only do you have to put an amplitude value in the volume register every scanline or two but you programmatically have to deduce each sample's value, either by calculation or lookup from stored samples.

Pitfall II has the advantage of the chip on the cart which does those other things which cuts out over 90% of the work otherwise required. All the CPU needs to do is read the output register and store the sampled value.

[+RevEng]

There's no denying POKEY is the superior chip, with more voices, finer frequency granularity, combined voices and filter. When 2600 games do well, it's in spite of TIA, and with great effort.

 

But TIA isn't as horrible as a lot of people think. I'll leave the very fine Man Goes Down 2600 homebrew theme here...

 

 

And with a bit of shameless self-promotion, here's my own 7800 homebrew theme, which uses a sweet spot in the TIA tuning...

 

[+FujiSkunk]

Not 100% correct I think.

The 2600 cart pinout has no place for an external audio (the way the 7800 does), the way I understand the DPC to work is that you can read a particular register that holds the amplitude of the multi wave generation that happens within the DPC and then send that to the 2600 sound register (which is the TIA).

 

So although the TIA does not generate the actual notes I believe it does play it, while the DPC is the generator and via HINT one can build the datapump, which is what Pitfall II does if I am reading the specs right.

 

Feel free to correct me if I am wrong.

 

Technically correct, but I still say it doesn't count. While the TIA is indeed generating the audio, I wouldn't say it's generating the music, any more than the digital-to-analog-converter in a CD player generates the music recorded on the CD's. The DPC could be attached to some other chip capable of acting as a DAC -- such as a POKEY, as has been mentioned -- and you would hear the same music.

[+phoenixdownita]

Pitfall II has the advantage of the chip on the cart which does those other things which cuts out over 90% of the work otherwise required. All the CPU needs to do is read the output register and store the sampled value.

All I wanted to convey is that with clever tricks and sample merging done elsewhere it's still the TIA playing it.

I believe that the fact that the 2600 does not have the horsepower to do it by itself (that is without the DPC) does not make the TIA less capable of playing samples (for some definition of samples I reckon).

 

But the Pokey is indeed better.

[+phoenixdownita]

 

Technically correct, but I still say it doesn't count. While the the TIA is indeed generating the audio, I wouldn't say it's generating the music, any more than the digital-to-audio-converter in a CD player generates the music recorded on the CD's. The DPC could be attached to some other chip capable of acting as a DAC -- such as a POKEY, as has been mentioned -- and you would hear the same music.

Not exactly, not the same music because now the actual circuit becomes important. A crappy DAC would sound like a crappy DAC, an interpolating DAC would smooth out the rough edges (especially important if you can only generate limited amplitude steps), an FFT circuitry can equalize the sound etc... so it is not the same.

 

I understand that given a 6507/6502 Pokey is the clear winner, I also suspect that it still wins having anything else (ARM or others powerful enough) pump data using both (TIA or Pokey) as amplitude modulators.

That's all I wanted to say. Sorry to derail the thread, but I am stickler, for long time I thought that the DPC was also actually playing the tune (via audio mix) and if the 2600 had an audio pin in the cart it would like have been the case.

[+FujiSkunk]

Okay, yes, different DAC's will produce different quality feedback. But, regardless of the quality of the sample playback circuitry, it would still the same chip generating the music, and that chip is not the TIA.

[Rybags]

The TIA has the huge weakness in that the CPU has to take part in video generation as well. On the computer the penalty suffered is DMA which at absolute worst might slow down from an effective 1.79 MHz down to about 1.25. And the jitter due to DMA timing not being evenly spread. But those things can be overcome to a fair degree.

 

TIA has the huge penalty in that the CPU has to be constantly active in the video generation process, so combined with the slower CPU to begin with, greatly reduces what can be done overall. In most cases, high quality sampled audio isn't worthwhile if it means everything else stops.

[+phoenixdownita]

Okay, yes, different DAC's will produce different quality feedback. But, regardless of the quality of the sample playback circuitry, it would still the same chip generating the music, and that chip is not the TIA.

I understand your point but then what about those systems that really only have glorified samples playback ICs .... there really is little to no "generation" just a pointer to a region of memory where the samples at a certain rate are stored.

Then at certain intervals the CPU changes the pointers as needed and around it goes .... it could even be a dedicated CPU just for that.

The may offer multiple channels for polyphony or they may rely on the external CPU to merge the necessary data into a single stream (dual for stereo support obviously).

 

Would you say that they do not generate the music?

[+FujiSkunk]

I understand your point but then what about those systems that really only have glorified samples playback ICs ....

 

Would you say that they do not generate the music?

 

I would indeed say that, at least given the context of the current discussion. We're asking which chip is capable of better chip tunes, not which chip is more capable of sample playback.

[Rybags]

Generating music on the most of the old computers is a CPU task. As a minimum you're walking through a song with a tracker then plugging note values into the sound generator.

For the Pitfall 2 cart I suspect that would be almost the same process. The offboard chip generating the waveform needs to know what frequency and wave type to produce which = the CPU plugging values into it (which in itself is a bit trickier than normal since 2600 carts have no write line).

 

An exception might be something like the Amiga. You can tell it to playback a long waveform then leave it forever without intervention. But in general that's not how it's done. Most music is done using short samples for instruments and there's CPU intervention each time a voice is to play a different instrument or frequency, and I believe ADSR also has to be done by the CPU.

[+davidcalgary29]

There's no denying POKEY is the superior chip, with more voices, finer frequency granularity, combined voices and filter. When 2600 games do well, it's in spite of TIA, and with great effort.But TIA isn't as horrible as a lot of people think. I'll leave the very fine Man Goes Down 2600 homebrew theme here...https://www.youtube.com/watch?v=PQPdbdQO7RYAndwith a bit of shameless self-promotion, here's my own 7800 homebrew theme, which uses a sweet spot in the TIA tuning...https://www.youtube.com/watch?v=0zCm1_5nYIU

Don't forget Chetiry! It has excellent in-game music on TIA.

[+RevEng]

Don't forget Chetiry! It has excellent in-game music on TIA.

Definitely top notch music in Chetiry! It's worth mentioning that it uses DPC, so the objections to Pitfall 2 in this thread would apply to it. I don't believe that takes away from this excellent game and it's catchy music in any way or shape - just that some people here wouldn't categorize it as a TIA accomplishment.

 

Stella's Stocking uses a similar soft synth technique without the hardware assistance, though only in the title screen, so Rybag's comments about it being a CPU intensive approach are spot on.

[Paul Westphal]

Get Tempest Xtreem from Video61. It has awesome music ( Amiga mod to pokey conversion )

[+phoenixdownita]

Generating music on the most of the old computers is a CPU task. As a minimum you're walking through a song with a tracker then plugging note values into the sound generator.

For the Pitfall 2 cart I suspect that would be almost the same process. The offboard chip generating the waveform needs to know what frequency and wave type to produce which = the CPU plugging values into it (which in itself is a bit trickier than normal since 2600 carts have no write line).

 

An exception might be something like the Amiga. You can tell it to playback a long waveform then leave it forever without intervention. But in general that's not how it's done. Most music is done using short samples for instruments and there's CPU intervention each time a voice is to play a different instrument or frequency, and I believe ADSR also has to be done by the CPU.

Wrt the DPC I believe the music is already in the ROM and the DPC is able to fetch and bitbang the "right" melody on its own but I may be wrong. Regarding missing the write signal you could always define a hot spot and piggy back on normal bus read access given the timing was fixed anyway.

 

The Amiga was exactly what I was referring to and I always considered it was playing the music, only time the 68K was heavily involved is to generate more than 4 channels by way of mixing the samples via the CPU, I believe there was a technique in which Paula was made to loop on very few words and have the CPU bitbang what it needed in those.

 

Arcades early on used a dedicated sound processor in addition to the sound generator proper, the same scheme was later used by the Genesis (Z80), the NeoGeo (Z80) and I believe the SNES (I do not know enough of the SNES SPU to actually be affirmative on that regard but I would be surprised otherwise).

The Jag had Jerry dedicated to it, the Saturn had a 68K, and the PS1 and the N64 had dedicated custom processors which I believe were plenty capable of being "programmed" somewhat independently and needed very little CPU support (at least that is my recollection).

 

It seems everyone recognized soon enough that you need dedicated CPUs to "play the score" to the sound unit proper (FM, PCM, ADSR or whatever they had) or have complex sound support to avoid taxing the CPU.

 

I believe only the 8bits were left with "use the main CPU" solution due certainly to cost cutting/containment.

[+davidcalgary29]

We all know that POKEY is no SID (C64), but comparing my (small) XL library with the VCS-one I can't find a game with

(much) better music and sound than some later 2600 games (for example: Pole Position, Crystal Castles, Pressure Cooker, Ghostbusters, Pitfall II...)

 

My 600XL cartridges are:

 

Blue Max (with 1064)

Pac-Man

Joust

Robotron: 2084

Pengo

Donkey Kong

Donkey Kong Jr.

River Raid

Carnival Massacre

Pole Position

Moon Patrol

 

opinions?

I think that's because most A8 NTSC commercial game development ended around 1986 and the few American ports that made it out by then were quickie ports from the C64 that took little advantage of POKEY. The games you've listed are from the early to mid '80s, and there wasn't a lot of standout music for most platforms, and it took awhile to develop this aspect of home computer gaming. If you compare your list with something like Trailblazer (1986), you'll see what I mean. You should definitely play some PAL games (NTSC ports) coded in the '90s to get a true appreciation for what POKEY can do -- some of the music in latter-day central European releases is amazing! I recall Hawkmoon (1993) as being particularly outstanding. And then there's Yoomp...

 

Had to edit this because I forgot -- for some reason -- Gyruss! The 2600 version actually has some pretty decent music, but POKEY really elevates the A8 version beyond the mid-range space shooter it otherwise would have been.

[Rybags]

The grunt work of deciding what note and waveform is still up to the 6507. But that's easy stuff that can be done during VBlank. The DPC creates the waveform dynamically based on up to 3 virtual sound voices.

 

The DPC in fact does more than just sound, it also does some of the graphics work. From what I can gather, both functions are probably very similar. Random number generation is also provided.

 

Here's a link to a US Patent describing the chip: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4644495.PN.&OS=PN/4644495&RS=PN/4644495

 

Here's another thread from a while back about the DPC: http://atariage.com/forums/topic/144075-how-exactly-does-the-pitfall-2-dpc-work/

 

 

From what I can gather, the DPC probably acts as a sort of "portal" to the Rom. By accessing the registers relevant to graphics data or sound, the DPC performs translation and address incrementing such that the required data is presented to the CPU, saving the program from having to do such calculations and leaving time for other tasks.

 

The functions of the chip weren't fully utilized, supposedly it also has line-draw assist which wasn't used. The chip itself was planned to be used to be used for more complex modern games but the video game crash meant it never realised it's full potential.

Edited September 8, 2016 by Rybags

[+phoenixdownita]

...

 

Had to edit this because I forgot -- for some reason -- Gyruss! The 2600 version actually has some pretty decent music, but POKEY really elevates the A8 version beyond the mid-range space shooter it otherwise would have been.

The C64 version of Gyruss had a pretty decent music too:

 

http://www.youtube.com/watch?v=yabHUJW2d8Y&t=35

 

And unlike the A8 cock-up it does not stop between waves waiting for you to get to the next screen. My experience though comes from playing an 800XL while Gyruss was an early title for 800, so maybe on it it doesn't do that (I had Sijmen [mr MyBIOS] patch a version to run on MyIDE ][ and he noticed the same thing)

 

Check here:

http://www.youtube.com/watch?v=KsGOQeF_Ifk&t=64

 

EDIT: I have no clue as to why the links are not embedded.

[+davidcalgary29]

Ooh, I don't like the C64 music -- sounds kind of...tinny to me. The graphics are nice, though. I always thought that this was something of a letdown on the A8.

 

Aren't the interludes true to the arcade original?

[Heaven/TQA]

There's no denying POKEY is the superior chip, with more voices, finer frequency granularity, combined voices and filter. When 2600 games do well, it's in spite of TIA, and with great effort.

 

But TIA isn't as horrible as a lot of people think. I'll leave the very fine Man Goes Down 2600 homebrew theme here...

 

 

And with a bit of shameless self-promotion, here's my own 7800 homebrew theme, which uses a sweet spot in the TIA tuning...

 

 

 

great tunes!