Hello, new to the forum.

I want to buy an AVS because of it's fair price and availability (e.g. easier to just buy right away rather than wait to get an NES HDMI mod) but there's one thorn in my side that keeps bugging me. For some reason, I find fake stereo mods where the NES channels can be split on left and right RCA audio leads to be very interesting and to me adds replayability for certain games. So that's what I like about the HDMI mod for a real hardware NES, is that this can be done with tweaks to the audio channels in the menu. It also can be done to an NES without HDMI of course.

But I'm a newb to soldering and don't want to do it myself, and I also would rather just go ahead and buy an AVS because of it's fair price and availability.

So long story short, will the AVS possibly some day add fake stereo support in a firmware update or something?
That would finally be the last thing to make me go ahead and buy an AVS for sure over all other options for NES consoles.

Doesn't it already send sound out via HDMI to both speakers?

By "fake stereo" he means separating different internal sound sources. It's a common NES mod.

Oh ok.  I wouldn't want that.  If the original NES was mono only that's what I want.  However, it is nice to have the mono sound come through both speakers.  Thanks.

 

Wait, the AVS doesn't support separated sound? I can't find any information on what kind of sound it produces.

Do you mean as in separating and sending the 5 various sound channels; pulse, triangle, and noise, to either the left or right channels?

I wouldn't know of any other way to change original mono sound to anything else. Well, actually there is another method which takes the original aidio , delays it by a millisecond or 2 and then sends it though to either the left or right to make it sound more "open", I'm not sure I'd personally use either of those, but options are always welcome of course.  

On a real NES CPU, the audio was output from the chip via two pins. The first pin carried the two rectangle wave channels, the second pin carried the triangle, noise and PCM channels. The output from these two pins was mixed together and the mixed signal went to the audio outputs. The stereo mod splits the channels by tapping the signals before they are mixed into one signal. The result is often unbalanced because the rectangle wave channels carry the main melody while the triangle channel is often used as a bass line and the noise channel is typically used for sound effects and percussion.

That would drive me nuts. I'd rather stick to mono.

 

Thanks for the replies. Yes I do mean fake (or some people call it true stereo). And I do mean fake stereo as in separating the two rectangle wave channels, the triangle, noise and PCM channels between white and red audio leads. Also I am aware there are a lot of people that aren't a fan of this, but for me it would be a neat feature to try some games in this way and add some replayability for me personally for certain games. Of course I wouldn't want it to be permanently set this way, but it would be awesome if there was an option to turn it on and off. Not all games would work well with stereo but some games could end up sounding pretty cool. So I was just wondering if this option could possibly be added in a firmware update some day. I definitely wouldn't want the NES gamers who will always prefer mono or dual mono to be alienated by no means, I just simply want the option to switch between dual mono and stereo with the channels split.

Well there's two ways to split NES audio. Only one works on real hardware.

JNES used to have an option to separate only the two rectangle channels. Sound very nice. Pulse 0 to the left speaker and Pulse 1 to the right. The rectangles are frequently used to produce chords so the stereo separation effect is balanced. Each rectangle gets a boost of +3 decibels and one speaker each. Triangle, Noise, and PCM remain centered. Impossible on real hardware but may be able to pull it off on an FPGA.

The other method that works on real hardware is to amplify the separate output pins from the NES CPU. This puts the melody (both pulse) on one channel and bassline / percussion on the other. IMO the second method (and only one possible on real hardware) just sounds bad.

The Hi-Def mod (and presumably the upcoming NT Mini) allow panning of all sound channels any way you want, but Brian seems reluctant to do this. It is possible the AVS runs a smaller FPGA limiting the options available for the menus. It's also less than half the preorder price of the NT Mini.

One could take stereo separation one step further with a pro logic surround system. Pulse0 on the left channel (+3db boost), Pulse 1 right (+3db boost), Triangle and PCM both channels, and noise both channels but inverted. This would place the rectangles in the left/right speakers, triangle and PCM in the front, and noise FX to the rear.

Ah ok, my apologies for not knowing all the technical aspects of the stereo mods for real NES hardware. I guess I should rephrase my question to 'will the AVS someday and somehow support true stereo in a firmware update someday, in some fashion?' I forgot that the true stereo mods for real NES consoles required pulling audio from two different pins of the CPU, that I did sort of know about but of course you made me remember that this is an NES console entirely in an FPGA so that kind of mod isn't possible with the AVS. So yeah, I'm just hoping, and wondering, if there can be some kind of true stereo mod option added in a future AVS update.

But if not, at least now I can understand why it can't really be done with the AVS.
 

I like the idea of separating the sounds into as many channels as possible. They mix when they enter the same room anyway, but fidelity is increased by having simpler waveforms sent to each speaker.

With a good 5.1 surround system, you could have the channels sent across five different speakers especially if using discrete 5.1.

With a pro logic decoder, you can selectively send a signal to each speaker using only analog or digital stereo hookups. Left only = left, right only = right, both channels = center, and both channels (inverted between right and left) = rear speakers. With Pro Logic II it is possible to further separate the two rear channels by panning left and right by a specific percentage. One caveat with the Pro Logic method is the subwoofer gets fed a mono downmix, so the rear speakers (which are inverted between channels) cancel out when fed to the sub. I would not recommend inverting the triangle (bass) or PCM (drums) to push to the rear speakers for that very reason. Also any device that downmixes to mono, such as a cell phone, will cancel out any signal encoded only for the rear speakers.

If you wanna keep it simple and support balanced sound on all devices, mono, stereo, or pro logic systems, then run Left = Pulse0 +3db, Right = Pulse1 +3db, both left and right = triangle + noise + PCM. You won't get anything out of the rears on a Pro Logic but you won't drop any signals either if you downmix to mono. Invert the noise channel on one side (right or left, doesn't matter) if you are using Pro Logic and want to hear the noise channel out of the rear speakers.

Thanks for that info!

 

NO. don't do that, at least with my stuff. it would sound weird, especially since i have pulse 1 as the lead and the 2 as a backup or secondary. some echo effects run the same track down both pulses but offset, which might sound cool split, but i dont think the chipset was developed for stereo, nor was the creation of music in games or homebrews.

mono through both speakers is nice. hell, bump up the bass (triangle) track for a more robust sound!!!

Two speakers making two different tones can preserve fidelity better than combining both signals and sending it through a single speaker. I like that having the digital source allows you to separate more channels than the available analog pins inside the NES.

When Brad Smith created MOON8, he made the Famitracker files for Side A and Side B available on his website rainwarrior.ca, and I did the whole "split stereo" thing and made a stereo mix CD out of it. It sounded pretty badass. A lot of times Brad Smith created an "echo" effect using the Pulse 0 and Pulse 1 channels, so Pulse 0 (left channel) was the primary melody, and Pulse 1 (right channel) was the echo. Other times when the music called for chords or multiple notes played simultaneously, he used dithering of the audio, and the resulting cornocopia was especially trippy through the speakers.

I do agree with you on one front, triangle and PCM should never be panned, because these provide the vast majority of the bassline effects in chiptune music, which needs as much woofer as possible...

Also there's an Atari hardware mod (similar to the NES hardware mod) to separate the two 2600 channels from the TIA into left and right discrete audio, but since a lot of developers used one channel for melody and one for explosions and sound effects, the effect was less than desirable, but it depended on the game.

I think stereo mods on any system designed solely for monaral audio depend largely on how developers chose to design their game as to whether the separation sounds good or not.

Which is exactly why I think having it where you can turn it on and off is a must, similar to a toggle switch on real NES hardware that has been modded for true stereo.

But the "real" mod sucks. Melody out of the left channel; bass and percussion out of the right. The only "balanced" way to do it is to split the two Pulse channels between right and left, which is impossible on real hardware but FPGA solutions like the Hi Def mod and NT Mini can pull it off.

I wish Brian would add an audio sub menu to the AVS and let us pan the six channels (6th channel being expansion audio). Then we could do whatever we wanted, even Pro Logic stereo mix assuming you could invert channels on one side or the other. I have no idea if the AVS could handle 5.1 PCM but that would be ideal for custom mixing.

 

Well I'll take that or any kind of stereo option that sounds good compared to just having only dual mono. I don't mind dual mono, it's just that I think it would be neat to be able to replay my NES games with some kind of true stereo.
 

Maybe!

 

 

So, how would you balance the five channels? Kosmic's suggestion of assigning the first pulse channel to the left speaker and the second pulse speaker to the right channel is ideal. I would follow that with assigning the triangle to the left and the noise to the right. But for the DMC/PCM channel, I would assign it to both channels. DMC/PCM is typically used for two things, voice samples and drum samples. Voice samples tend to be mono and drum samples are typically used for later games.

Triangle should also go in the center because it supplies the baseline for many soundtracks. Noise channel could go to the surrounds (invert one side) on a Pro Logic system for cool effect, but triangle and PCM absolutely need to go in the center for maximum bass output.