Separate Audio Output with Digital IO Board

[Gerri]

I have a question regarding Audio. Can the Mister Digital I/O board output the sound via the optical output via 3.5 mm jack? Normally I do this via the HDMI output. I have here a BenQ BL912 monitor that has no speaker, and must output the sound separately to an active speaker.

I ordered the Mister with the Digital iO board, but I'm not so sure if that was a good decision. For the 2 Ram module I did without the analog connections.

I would be happy if someone can help me here.

Many thanks!

Gerri

[Xbytez]

The digital IO board only supports optical audio out via the 3.5mm jack. It has no line level output at all for analog audio. Easiest solution is output sound via 3.5mm using mini TOSlink cable into a DAC, then connect the speakers to the DAC.

[Gerri]

Does it make sense to do without the analog section for 256 MB Ram, or will I have no bottlenecks with 128 MB in the future?

[AngelicLiver]

The amount of RAM isn't really the bottleneck, it's the potential bandwidth requirements some potential cores may need. It this point it's purely academic so I would not get too hung up on "future-proofing" your MiSTer build with a 2-module setup. 128MB is really only needed for some of the larger Neo-Geo ROMs.

PlayStation doesn't need 2 modules (in fact you can use a 32MB module alone), Saturn looks like it will be fine with 1 (but this may change) and Jaguar it's still very early days. Cores beyond that are a ways off and may very well be targeting significantly larger FPGA platforms.

[Gerri]

Thank your for your explanation.

In another forum I have found following hint to the Digital IO Board.

>> The analog board also has TOSLink output combined with the analog mini-jack connector.

Wouldn't that mean that I can output audio through this port via 3.5mm connector as well? I´m a little bit confused.

[jca]

With the analog board you can connect either an optical cable or a regular audio cable but the quality won't be as good and have annoying "pops" when starting cores

[Gerri]

So I would have a better sound via digital board?

[jca]

No, the quality problem refers only to the regular audio output, if you use optical it will be the same as with the digital board. Sorry for the confusion, I should have been more precise.

[Gerri]

Thank you very much the help. You have helped me a lot.

[Stinky]

Get an HDMI inline audio extractor they're fairly cheap. I used to use one with my xbox360.

[Malor]

So I would have a better sound via digital board?

The sound via the digital board comes out as a standard S/PDIF connection, and is exactly the same as the audio part of the HDMI signal. It will run at 96K, too, which is nice. So you'd plug a S/PDIF cable in (called Toslink in Europe, I believe), and plug the other end into a device that understands digital sound. I'm using a receiver here.

If you have a reasonably modern receiver, you can also use two HDMI cables to put it between the Mister and the monitor. Depending on the receiver, however, this can add lag or video issues, as the Mister is often doing some rather oddball things with its output. Running separate S/PDIF and HDMI cables gives you the exact same signal, while sending the video directly to the monitor without interference.

Any DAC with a S/PDIF input should work, you don't need an actual receiver. But if it doesn't also have an amplifier, you may need one if you want to drive speakers.

There's also a mini-optical connector that plugs in via a 3.5mm headphone-style jack. I don't think that jack carries analog audio, however, I think it's just an empty barrel connection with an LED on the end for the hybrid cables. Using the standard larger connector is probably going to be easier.

edit: in other words, the hybrid headphone cables have an optical core, and then a copper surround to carry an analog signal. I think Apple pioneered these to save on port space, so they could cram both digital and optical into one jack. AFAIK, the jack on the digital board doesn't do the analog part, it only uses the fiber in the center. The bigger S/PDIF cable is entirely optical, and is super easy to find, so that's probably what you want to use.

[Gerri]

I think that an adapter from HDMI to VGA will help me. The adapter I found has a normal output 3.5mm. I'm just not so sure if I need an extra DAC.

[Malor]

I think that an adapter from HDMI to VGA will help me. The adapter I found has a normal output 3.5mm. I'm just not so sure if I need an extra DAC.

I don't understand how HDMI to VGA could possibly help. VGA doesn't carry audio.

The digital board emits a standard optical signal via both a 3.5mm jack and a standard S/PDIF jack. AFAIK, it does not emit analog audio at all, period. You will need a DAC of some kind if you want to get sound out of the digital board. You may also need an amplifier to drive speakers.

You can get analog sound out of the analog board, but the quality will be reduced, possibly quite sharply. Digital sound to a reasonably good DAC will give you the best results.

[Bren McGuire]

I think that an adapter from HDMI to VGA will help me. The adapter I found has a normal output 3.5mm. I'm just not so sure if I need an extra DAC.

Get something like this:

20220701-000324-crop.jpg (74.02 KiB) Viewed 8777 times

It converts the Toslink/SPDIF optical out of the Digital I/O board to a standard 3,5 jack analog output.

Here's a link where to buy one: https://aliexpress.com/item/1005003984796338.html

P.S.: disregard the "USB Wireless" writing, I've no idea of what's that supposed to mean.

[mist-rich]

Can anyone please confirm I can use a TOSlink to 3.5mm (Aux) lead into a DAC? I'm not sure if such a cable only works one way (my DAC only has 3,5mm input).

Thank you.

[Goingdown]

I don't understand how HDMI to VGA could possibly help. VGA doesn't carry audio.

No, but hdmi does. And with hdmi to vga adapter with 3,5mm audio jack one can separate video and audio from hdmi connector.

Something like this https://www.amazon.com/Cable-Matters-Ad ... B008O7RH5C

No need for io board. Just make sure that adapter supports direct video.

[grizzly]

First what IO board do you have?
You do need the Digital IO board and from what i now they only have a 3,5mm mini toslink.
So if your DAC only have a 3,5mm mini toslink then you will need an 3,5mm to 3,5mm toslink cable.

Or you could use an adapter like this https://www.amazon.com/Digital-Fiber-To ... 074Z416CG/
But if you already need to buy something why not buy a cable with the right ends on it right away that will cost about the same.
And you will not have an adapter that will make the cable stick out longer from the port with the increased risk of breaking the port, plus one more connection can cause more problems (not very likely but the risk do increase).

So buy a cable instead is my tip!
Like this for example https://www.amazon.com/Digital-3-5mm-Op ... 08W3NR1RG/
These cables can be hard to find on amazon/ebay and other stores since many stores do not have a category for them and the search is useless and will only give you results for the toslink to 3.5mm toslink cables (the one you already have!).
What worked best for me now with a fast look was using google and searching with this.
"mini toslink" to "mini toslink"
And yes leave out 3.5mm since that seems to give so much more crap to sift trough.

[grizzly]

And one more thing if you use the io boards toslink you will need to flip a switch on the DE-10 to make it work.
See https://misterfpga.co.uk/mister-fpga-ho ... -io-board/ for more info!

[FoxbatStargazer]

I think that an adapter from HDMI to VGA will help me. The adapter I found has a normal output 3.5mm. I'm just not so sure if I need an extra DAC.

I don't understand how HDMI to VGA could possibly help. VGA doesn't carry audio.

Most cheap "HDMI to VGA" adapters have a built-in 3.5 mm jack to output the HDMI audio as analog. Not as good results as a DAC but it can still be better than the Analog I/O's particularly poor analog audio.

[mist-rich]

First what IO board do you have?
You do need the Digital IO board and from what i now they only have a 3,5mm mini toslink.
So if your DAC only have a 3,5mm mini toslink then you will need an 3,5mm to 3,5mm toslink cable.

Or you could use an adapter like this https://www.amazon.com/Digital-Fiber-To ... 074Z416CG/
But if you already need to buy something why not buy a cable with the right ends on it right away that will cost about the same.
And you will not have an adapter that will make the cable stick out longer from the port with the increased risk of breaking the port, plus one more connection can cause more problems (not very likely but the risk do increase).

So buy a cable instead is my tip!
Like this for example https://www.amazon.com/Digital-3-5mm-Op ... 08W3NR1RG/
These cables can be hard to find on amazon/ebay and other stores since many stores do not have a category for them and the search is useless and will only give you results for the toslink to 3.5mm toslink cables (the one you already have!).
What worked best for me now with a fast look was using google and searching with this.
"mini toslink" to "mini toslink"
And yes leave out 3.5mm since that seems to give so much more crap to sift trough.

Thank you Grizzly I'm trying my best to understand - I find the audio world more confusing then any other computing area. I have the analog IO board and the Soundblaster G6 DAC (the line out goes to my speaker):
https://uk.creative.com/p/sound-blaster ... lasterx-g6

Just so I understand - is a 3.5mm AUX cable different to a 3.5mm toslink cable? (and is toslink and optical the same?)

[mist-rich]

It's ok, I have bought another DAC/Amp now that has optical in and another for 3.5mm so my 2 devices (Mister + Computer) will be covered (fingers crossed) as current only allowed 1 input.

Still interested in knowing if optical/toslink and s/pdif are all the same - the more i read online the more confused i get

[grizzly]

Is optical/toslink and s/pdif all the same?
Yes and no!
Hope that cleared it up for you


optical/toslink is most likely the same if we talking audio, there have if i remember correctly been 2-3 other optical interfaces for audio that is NOT toslink and/or s/pdif, but none of them survived for long.
Then there have been optical for video/and other stuff but as said doesn't matter for audio.

toslink and s/pdif are kind of the same but not, toslink is optical and s/pdif is electrical (as in cable) but the signal before and after it has been transformed to and from light is the exact same as s/pdif.
So toslink is s/pdif but in light form instead of electrical.

There are usually 3 (or kinda 4) different connectors that is used.
1, The standard RCA connector for spdif (electrically).
2, The bigger toslink connector for toslink (optical).
3, The standard 3,5mm audio jack most times it will have both spdif and toslink (but not on the misters digital io board, there it is a combined regular 3,5mm stereo output and toslink).
4, The standard 3,5mm audio jack without the toslink but s/pdif.

And there have been a couple more contacts but they are very, very rare.

spdif-vs_optical.jpg (31.32 KiB) Viewed 8517 times

[mist-rich]

- but the signal before and after it has been transformed to and from light is the exact same as s/pdif

That has helped and has cleared up my confusion , thank you grizzly

[Malor]

The fiber and the copper S/PDIF signals are effectively identical, but I've come to strongly prefer using optical, because that electrically separates the source and the receiver, so it doesn't contribute to potential ground loop hum. That's caused by a difference in ground potential across two or more devices. It's super annoying, so I like to use fiber to preemptively avoid it.

Grizzly's image there shows you the two connectors, on the right side. The bigger one is fiber-only, and is older. The second combines both a 3.5" copper connector on the outside (a standard headphone jack, basically), with an optical core, exposed at the very tip of the cable. I avoid these cables for two reasons. First, they typically carry an analog audio signal on the copper, which makes for easy confusion between the two, so you end up playing back analog instead of digital. Second, that connects the two devices electrically, potentially contributing again to ground loop hum. I try to stick with the bigger, optical-only connector, because you can't get that one wrong (if you can hear sound, it's being sent digitally), and it doesn't have electrical side effects.

If you have an analog I/O board, though, I gather that's not an option; it sounds like that board has only mini-Toslink.

[mist-rich]

Thank you Malor, that is useful and has helped further

[Malor]

A cable like this one:

https://www.amazon.com/StarTech-com-ft- ... 00016W6Y6/

looks like it would work to adapt from a mini-Toslink to a standard size Toslink/SPDIF. If your other end can take the bigger cable, this should allow you to connect fiber-only, with no copper connection.

I don't actually know for sure that the analog I/O board has a mini-Toslink, so make sure it's there before buying anything.

[mist-rich]

Other end (my DAC) allows that bigger cable so I think that could work nicely (fingers crossed). I'll double check I/O board has mini toslink first just to be sure and let you know how it goes

- even if it doesn't, I definitely feel more clued up on this area of audio now so it has been well worth it,

[grizzly]

I was going to say that you need the digital io board for optical out but seems not, i could almost have sworn on it.

But you can easily check if your io board have optical or not just look for the red LED behind the 3,5mm port if it´s there it should work.
See pic from misterfpga.co.uk and you see the LED to the right in the pic.

MiSTer-FPGA-v6-IO-Addon-Board.png (929.27 KiB) Viewed 8256 times

[mist-rich]

Just looked and it's there i'm good to go.

Video, controller and now sound sorted (almost) , won't be long before I get to hear as well as see some classic goodness.

I'm going to replace my Soundblaster G6 DAC with a Cambridge DacMagic Plus which if i'm right should allow me to input my gaming PC + Mister, and using the source button on front to switch. Fingers crossed.

[Malor]

Before you buy a new sound card, check your motherboard audio. Most motherboards now have a large optical out on the back panel, so you could just wire it up. However, that only carries stereo sound or DTS (compressed) 5.1 multi channel. You won't normally have any way to do DTS compression, except when playing back a movie with DTS encoding, so most of the time that would be stereo-only.

If you have a receiver with 7.1 analog inputs (which were very common 10 to 12 years ago, but are going away now), you should be able to connect from the analog outs on your motherboard. Cheapo motherboards will sometimes be a little noisy this way, but you get multichannel. You can also run a S/PDIF at the same time to play back DTS-encoded movies, but honestly, the DTS decoders in most modern players are fine, and letting the software decode is easier than switching back and forth between digital and analog.

The second-best method to connect to a receiver over HDMI, because this can carry 7.1 audio and any form of sound compression. (like DTS-HD or Dolby TrueHD, both of which are lossless.) However, many receivers add lag, especially older ones. The ideal approach is to use a monitor or TV with e-ARC support, so you connect HDMI to the TV, and then connect from the TV's e-ARC output to the receiver's e-ARC input. This gives you everything; bitperfect audio transmission with at least 7.1 channels, I think more with Dolby Atmos, and the minimum possible video lag. But you need quite new equipment to make this work.

Note that all of this doesn't apply to the MiSTer itself, just to your PC. The Mister only does stereo. It can output 96KHz, however, which apparently better for resampling cores that use weird audio rates. (I think there's at least one core that's outputting at something like 33KHz, which is really weird.) So you may want to turn that on once you get your cable. Nearly all receivers speak 96KHz just fine.

The option is called hdmi_audio_96k, and you set it to 1. (hdmi_audio_96k=1). Despite the name, it also applies to the S/PDIF. If you don't get any sound, set it to zero, which will drop back to the default 48KHz after a reboot. That will work with any receiver with optical in, no matter how old and/or busted it may otherwise be.