Sound

Shrek Asked

Are you trying to tell me, that a system which could possibly display 100 objects on the screen, has the same sound capabilities as 2600? 2 channels? With that lousy limited pitch? Can something be done with this? I'm a bit surprised (and it isn't nice surprise).

Eric Ball Answered (AA)

The major limitation of the TIA sound generator is it only has a 5 bit frequency divisor. This really limits the number (and accuracy) of notes it can produce. But, it is possible to make decent original music and sound effects with the TIA.

POKEY (potentiometer & keyboard processor) was created for the Atari 8 bit computers as a keyboard & paddle interface. It contains an improved version of the TIA sound generator with 4 channels each with an 8 bit divisor (versus 2 channels with 5 bit divisors) and pairs of channels could be linked to create a 16 bit divisor. This provides the required resolution for accurate notes, and thus decent music reproduction. (Though still with fairly limitted 1 bit polynomial waveforms.) 

Mark Rathwell Answered

Yeah - probably an issue of space and cost. The 7800 has both unique hardware and 2600 hardware on the motherboard. To maintain 2600 compatibility, it has 2600 sound. But (for space and cost), they didn't have a secondary sound chip to take over TIA chip's sound, the way that MARIA takes over for graphics.

The 7800 hardware does allow you to place a POKEY soundchip in cartridges to give the 7800 6-channels overall (2 voices in TIA, 4 in POKEY) but only two games use it … Ballblazer and Commando. With Cuttle Carts, you could theoretically make POKEY sound driven games without the expense of building a POKEY cart.

Eckhard Stolberg Answered

There is an audio recording of a panel discussion of the GCC designers at the 20th anniversary party for the 7800. In it on of the hardware designers mentiones that that had ideas for a better sound chip, but didn't implement it, because they had so little time to finish the design of the MARIA graphics chip. So they were planning of creating a cheap sound chip later that could be put on all game cartridges or possibly on one sound passthrough cartridge. But since there were problems with the Tramiels when they took over Atari, GCC never finished the sound chip, and the audio connection on the cartridge port was only used by Ballblazer and Commando, which both had an addition POKEY chip in the cart.

So unless you design yourself a cartridge with an addition sound chip in it, then all you'll get for your game will be TIA sound.

Manuel Rotschkar Asked

Hm… but "Asteroids" for example doesn't sound like a TIA at all in MESS. Is the emulation so far off here?