Retro Surround Sound?!

[TrekMD]

Wow, sounds impressive since you're doing this for the 2600!

[retromod]

well the technology behind is quite easy to port to other systems (as I done before for coleco, 7800, intellivision). The pcb for the new surround sound module is currently in prototyp production. 5x4 cm size fitted with one MCU. I currently try to reduce the cost by replacing the audio amplifiers with single chips instead of using passive components. This morning I found a chip which may be the right candidate. This saves room on the PCB and lower the costs.

Goal is to have a real stereo surround solution in a small form factor by mid of next month most likely with some kind of bus system so it is easy to assemble and to combine functionality (for example using one MCU for all components instead of different one).

And as usual I'll dream about the next gen of "Special Editions" using Atari 2600Jr. As I have some broken Intellivisions in stock I'll think about white versions as well may be with RGB..... ;-). Repair of these console is quite expensive, I found a source for the GFX (about 25 Eur) and audio chip (10 Eur) but with shipping cost it is equal to an intellivision console fully assembled with games on ebay.

[retromod]

Improved firmware for the Intellivision Stereo/Surround Mod, now it offers a better stereo experience out of the box.

[retromod]

I found a great article about sound effects and plan to adapt an audiophonic algorithm to my stereo/surround mod. That means if it work as planned you'll get an impressive audio output for each console.

Here is a great sample for such an effect:
http://gprime.net/flash.php/soundimmersion

If it works as planned all retro consoles will be at the same sound level than the new xbox one, which is currently the only one offering audiophonic output.

[TrekMD]

Well, that was cool to listen to.  Definitely immersive!

[retromod]

Today I tested the first implementation and it sounds great. Not a big jump on Atari 2600 as sound is a little bit "thin" during game play of most modules. So I expect more on Coleco Vision and Atari XEGS systems. But it is definitely worth to add to the existing mod as it also implement a sound wall for normal audio mode (currently only the left speaker is working if stereo is switched off)

Price tag is very low due to MCU approach and a few additional parts. More an overall Mod update 
First implementation most likely in the Atari 2600 Woodgrain Special Edition or Atari 7800 Druid Edition.

[retromod]

After successful testing of the new 3D audio feature I completed the circuit drawing yesterday. I also ordered newer smaller components (50% smaller) and will redesign the Atari 2600 PCB within the next days.

there will be a combined Composite/Stereo/3D Audio/Joystick Pause Mod PCB which excluded Woodgrain and Darth Vader specific needs for the video system. The required logic for that type of console is on another adapter PCB which is hooked on top of the TIA. So in future there is one PCB for Atari 2600 for all models, which lowers production costs and simplifies the modding process in common. I also moved functions to existing MCU so this reduces parts. Currently there are 4 small processors on the board in favour of a big one (switching to FPGA seems to be the next logical step to get more speed on one monolith approach). Size of board will be most likely stay the same (as Darth vader and Woodgrain logic is replaced by pause and 3d Audio
)

I look forward to the Coleco Vision version and the finalization of the Intellivision mod (which is currently in improvement stage to ensure it works with all kind of monitors). The redesign of the Atari 7800 made a big progress, too. I'll try to get some additional noise reducation logic on the board for a "final" audio mod.

[retromod]

successfully tested the new Stereo/Surround with noise reduction and 3d Audio. There is no better Audio currently! Together with the AV mod you'll get the best AV picture and best audio available on Atari, Coleco and Intellivision.

A good old friend visited me these days and he confirmed he never heard a better sound or saw a better picture on the Atari 2600 consoles. he was also shocked that my AV Atari 7800 output looks much better than his S-Video output bought from an "expert" a while ago and fitted with all kind of additional chips to get a better picture. After he saw the Atari 7800 Druid prototyp he was very excited to buy one as soon as it is available. But he doesn't want my personal sign on top..... time to re-think friendship 

[retromod]

interesting to read my forecast for upcoming mods and technical relevant details.

Finally the time filtered out the wrong decisions made. An universal, cheap AV-mod on top of the TIA is reality. With the current offerings in ebay there is no soldering required anymore inside of the console. So my assumptions were right here.

The all-in-one mods were not really a big success as one fault on the board or failing component renders the whole PCB unusable. So instead of cost reduction it finally increased them. So my current mods only combines the most common one which then have a lower price tag of course. the current seller is the AV+ and Stereo/Surround board for example which seems to be the standard specially for Atari fans.

3D audio was finally the right step but increased the cost and complexity/size of the PCB. So it is dropped in favour of the upcoming Real Surround mod. the technology behind 3D audio will be finally used on other consoles already having stereo implemented.

[retromod]

I've optimized the stereo surround mod and it now allows to fine tune it's output. So implementing a switch to select mono/stereo/stereo+surround is now possible. It has a noice reduction implemented and the firmware was optimized giving a better sound experience. Due to the changes an update of older mod's is not possible.

The RealSurround efffect currently in development (the player location is calculated and used to alter the sound output) requires some changes in the overall design so this is a good time to optimize the firmware as well and prepare it for future use on better MCU's (as it will be combined with the video part).

It seems that all the development efforts finally result in one board driven by one MCU for video, audio and additional features like OSD (for setup) and pause (moving that feature into existing MCU would reduce the costs, too).

I also noticed that my youtube videos are still outdated and only showing the first incarnation of the mod. Simple Stereo and the new design is not reflected, too. Seems I must add that task to my schedule as well.

[retromod]

This is a console offered regulary on ebay. The clou is the switch on the left side on the bottom of the console allowing to select mono or stereo or stereo+surround on demand. The console itself is modded to use a 5V power supply (e.g. USB if required). Heating is lowered, components lives longer and this also prevents accidently damage in some cases (due to a design flaw you might destroy your custom chips if not properly handled).

The function keys and cartridge slot is silver as well, offering a valuable handling. A hidden power LED is included as well. An exclusive CX40 joystick is already included: metal switches inside, silver design outside.

last but not least it offers the best composite picture as it has an AV Plus mod.