resample SNES audio to 96 kHz

I've known about the cirrus logic mod for the snes that pushes at 32.040khz signal. Maybe like a year ago I found this:
http://www.head-fi.org/t/740288/super-nintendo-spdif-dacs-and-you

Someone had re-sampled the non standard signal to a convenient 96khz. I built the board but got nothing out of it. I thought perhaps my receiver didn't like the signal, IDK. At the time I bought double parts because I wanted to test the board out on an N64. After not working, I threw the parts in a bag and went on with my life.
I Recently did the hdmi mod for the N64 and got me thinking about the mod again. I soldered a new board up with the spare parts and sure enough it works great! I haven't seen this discussed here on the forums at all so perhaps someone else here will be interested.

 

You know 96 kHz is placebo.

 

192 kHz is placebo. 96 kHz has it's place.

 

Not from a lower quality source though.
Resampling something from 32 to 96 doesn't magically add more information.

 

Where did I say I made the snes audio sound better?

Whats not placebo, is taking a non standard format that has the chance of jittering etc and resampling it to a standard format a receiver handles fine.

If your receiver can handle the 32.040 then yeah this mod is worthless to you.

 

Just like to point out, my post wasnt saying to not resample - like you quite rightly say, getting it to a standard rate will likely be sensible for many receivers.

 

I bought those components but never ended up building the circuit. I think L-train made some revisions to the PCB after the time I ordered it from OSHPark. Meanwhile, the old mod works OK with the receiver that I use (as mentioned in the thread). This somewhat standardized output version would certainly help provide a more universally compatible digital audio out for receiver compatibility. I will probably finish it at some point, but the project backlog demands it take lower priority.

 

Congrats on getting it working citrus! You guys hit the nail on the head, compatibility with modern receivers was my primary goal and audio quality was a very close second. Perhaps I should have made it clear that it's not meant to improve the sound quality of the digital audio coming from the SNES, but rather a way to convert the SNES' digital audio to a more standard sample rate as losslessly as possible.

I think people should try out the regular mod first like CkRtech has done to see if it works with their receiver/DAC. borti4938's nice little boards are inexpensive and make the mod really easy to build and install.

 

First off : WOW great job. What you just developped is something i was looking for.

I would love to record samples from my Snes but always had noise/fuzz problems. Your work seem to avoid it once and for all. I use modern soundcards and DAC so your mod might be useful..

Do you take comissions for this kind of mod ? : D

 

If all you need is SPDIF over coax, I can sell you my original version fully populated. It's functionally identical to v1.1 but without optical support. Unfortunately I'm unable to do installs for this mod due to lack of time, but if you're able to do it yourself or have someone else do it for you, let me know.

 

Well all i need is to hook up the Snes to the TRS input of a soundcard. I won"t need to convert anything. My problem might be related to a ground signal or something. From the head fi forum i can read this : "The sound had much better range (subwoofer kicked off a bit more), and the noise caused by the analog video signal bleeding into the native analog audio output was gone."

I suppose that i have the same problem when i hook up my SNES to my soundcard. A fuzz noise can be heard in the background..
Also being able to get rid of the statics and upsample the 32khz audio signal to 44khz nearly natively is a big plus, especially with a modern DAW (it does support 32khz, just like my soundcard but hell i'm not going to work to work in this kind of environment ^^)

 

I think you'll always get that noise if you use the analog outs. Better shielded cables will help reduce it, though. You can try building custom cables using the multi-out connectors from Helder here and separating the audio and video with well shielded cable, but to fully eliminate the noise you need a digital audio mod.

 

Digital audio seems really complicated especially when it comes to recording..
If I use the SNES just for playback then a simple digital audio reciever/amp should do the trick.. but if i want to record the audio from the SNES I will have to use toslink device and good frequency clocked soundcard ?

Am I saying bullshit ? ^^

 

The digital audio receiver still needs sync it's clock to 96khz in order for it to correctly receive the signal and convert it out to analog for you to hear it through your speakers. If you were to go into the receiver via an analog input and the receiver uses some form of DSP on the signal before spitting it out, then the receiver would be sending your analog signal through an internal ADC, processing, then going through the same DAC that was mentioned in the 1st sentence to convert back to analog to go to the speakers. By going in digitally, you've eliminated two conversions from the chain, the DAC in the SNES, and the ADC in the receiver. This is a good thing.

With this 96khz output you've done a few things, you've tapped the direct digital signal and bypassed the SNES' subpar DAC and run through a hardware SRC(Sample Rate Conversion) IC to bring it to 96khz. This makes it so you are compatible with modern, as well as professional grade DAC's, and able to more easily get the unconverted(except for sample rate) digital signal recorded straight from the system. On playback this means that somebody could use studio standard conversion to send the signal out to the amplifiers such as This or This for a really excellent sound. On the recording end, it means that you will more easily be able to use a soundcard or audio interfaces digital inputs, SPIDF or TOSLINK, to get the sound from your SNES recorded. All that needs to happen is that the clocks can sync and what comes from the SNES should be Exactly (barring any errors in transmission) what you have recorded. This mod makes it WAY easier for that to happen as you will have a hell of a time finding DACs or digital inputs that will sync to 32.04KHZ and a very easy time finding ones that will do 96khz.

Some argument can be made against the SRC as any SRC has generally negative effects on the sound quality to the point where mixes done at 96khz are very often in mastering converted out to analog and reconverted to digital at 44.1khz vs using SRC (Yes this is sometimes just for the use of analog signal processing, but rather than capture it back at 96 and run SRC, they get better results going in at 44.1). In this case, just bypassing the internal DAC and allowing the use of proper DACs gains you way more than you would lose via SRC. If it was a solid 32khz native, it actually wouldn't matter at all as 96khz is a direct multiple of 32 so every word would just get repeated twice more in the bit stream. But, the .04 khz kinda makes it a tad more complex.

 

Thanks for the very detailed answer. So basically i need another soundcard that can support digital Input. For now i'm using focusrite forte which is an excellent sound card but this one lacks of the digital In.
Indeed, 32.04 is complicating this task a lot more. Also the mod gets rid of a lot conversions, thanks for the explanation.
A simple Roland FA 66 should do the trick then : ) It has optical and coax Inputs and seems to do the sync job.
Ah .. and i need to mod the SNES now haha

 

Ah, the former Edirol. They weren't terrible little budget interfaces. It will do the job. Just don't pay full price for it as it's budget level gear from 2007.

 

Haha yeah i know it's a cheap (and a bit old) soundcard but it has a lot of features on it. It's clearly the best product in this price range..
I wish i didnt choosed the Presonus Audiobox a few years ago.. what a crappy device !

 

Ugh, don't get me started on Presonus or M-Audio for that matter.