Digital HDMI Audio vs Analog BNC Coax Audio from RetroAccess

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Ikaruga11
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Digital HDMI Audio vs Analog BNC Coax Audio from RetroAccess

Post by Ikaruga11 »

So I'm looking into audio for my setup and would like to know if the analog audio from RetroAccess BNC coaxial cables is as sharp and clear as lossless digital audio from HDMI, TOSLINK, SPDIF, etc. Would there be any discernible difference to the human ear? I'm wondering if surround sound formats like Dolby Surround for SNES/N64, Dolby Pro Logic II for GameCube/Wii, and other formats like LPCM, Dolby Digital 5.1/7.2 and Dolby Atmos would be affected differently with analog audio vs digital audio.

My analog BNC coax cables from RetroAccess are going to be as short as possible (3-6ft.) and these BNC coax cables are supposedly fully shielded with the highest quality components and construction on the market.

Also, all of my HDMI consoles will be using an HDMI switcher and some splitters as well so I'm not sure if that will change anything.
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NewSchoolBoxer
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by NewSchoolBoxer »

Ikaruga11 wrote:Would there be any discernible difference to the human ear?
An audio question, I love it. Is a broad question when you aren't specifying consoles. NES mono or bad audio model Genesis/Mega Drive is going to be more tolerant of audio degradation than CD-quality PS1 sound. PS2 has native digital out over TOSLINK and you should definitely use that over RCA analog audio.

Going from RCA to lossless digital audio, you pay a small cost in the ADC conversion but then you preserve the quality all the way to speakers. I'm sure is worth encoding audio on HDMI with your existing upscaler or buying a $20 RCA to TOSLINK/coaxial converter. I'm working up to this. Issue is how much audio degradation do you get before the conversion?

No one can dispute that coaxial cables gives highest possible analog quality for unbalanced signal*. More a matter if cables are thick and shielded enough and copper versus cheaper aluminum or steel crap, or if cable length is too long.
That said, best audio cables will have shielding for low kHz audible range and best video cables will have different low MHz shielding. Further, if you care about audio, you shouldn't run analog audio wires in the same jacket letting video crosstalk on audio and being forced into thin cabling. Why BNC is best and RetroAccess has BNC cables. However, audio and video are still in the same jacket for, what, 75% of the length? Cables are forced to be VGA / SCART 26 AWG or thinner versus separate BNC that can be thicker and better shielded 18-22 AWG.

RetroAccess BNC breakout is good option but here is what I'm doing for better option:

--I bought entry level Logitech Z333 2.1 speakers that take analog RCA and 3.5mm. You got digital audio on HDMI television or can run to digital speakers from television's output jack. Can roll with that.
--Split audio from video at the MUTLIOUT LEVEL stage and do not run them together. For PS1 RGB over SCART/JP-21, do a multiout chain. SCPH-1160, 10080 and 10130 all extract audio at the multiout and can attach SCART/JP-21 multiout onto the connector.
--No official option for SNES and N64 RGB but see next option. I don't know about Sega consoles.
--Other option is maxtherabbit's or Chipnetics Nintendo and Sony VGA (RGBS+HV) multiouts that have 3.5mm audio port. Both post here. I have and like maxtherabbit's but want to compare against other products for science.
--Audio specific cables, I think I'll try Monoprice RCA 22 AWG meant specifically for audio.

Running HDMI consoles, yeah just stick with audio in the HDMI cable or TOSLINK. I think you're fine with splitters. Only issue I elaborated on is extracting the analog audio from running alongside video before you convert it to digital. HDMI isn't rated for very long distance but I don't assume is issue here.

*ignoring expensive litz cable specifically for low kHz audio
Last edited by NewSchoolBoxer on Sat Jan 15, 2022 1:23 pm, edited 1 time in total.
jd213
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by jd213 »

Audio quality definitely can depend on the console no matter how good the cables are, in my experience there's always at least a little hum/buzzing when using analog, until you get to the PS1/Saturn era. And the Saturn definitely needs good cables to get clear audio over analog (there's also an SPDIF mod).

If you want truly clear audio quality on 16-bit systems and earlier, using FPGA and/or digital output modded systems is probably best.
fernan1234
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by fernan1234 »

jd213 wrote:Audio quality definitely can depend on the console no matter how good the cables are, in my experience there's always at least a little hum/buzzing when using analog, until you get to the PS1/Saturn era. And the Saturn definitely needs good cables to get clear audio over analog (there's also an SPDIF mod).
Yeah to some extent. My experience has been that Retro-Access coax cables are good enough to let you not hear any audio buzz or interference, on most systems, unless using headphones at high volume levels. I have coax (D-Sub, but they use the same coax as the BNC ones) cables, for instance, for PS2 and Wii (with a WiiDual installed), and I exclusively use headphones. The digital output for each system is definitely better than the analogue one, not really in quality but in having a lower, undetectable noise floor.

So basically any system that has digital audio output will be a preferable choice, but coax analogue cables will be just as good in a speaker setup, ant the latter will also be good enough for pretty much any analogue out only system. The only exceptions I deal with are the NES, all of its models being buzz machines, and the unmodded Sega Genesis model 1, whose stereo output also has a very high noise floor.
jd213 wrote:If you want truly clear audio quality on 16-bit systems and earlier, using FPGA and/or digital output modded systems is probably best.
I agree with this but again only for a couple of cases, like the two I mentioned above. For the NES I just use an NT Mini Noir, since I'm so "purist" about the NES that I only want to see its original composite output, but not purist enough to put up with the buzzing audio of original HW (especially since I use headphones in which case it becomes unbearable), so this gives me the best of both worlds with a negligible compromise in accuracy. For the model 1 Genesis though I just accept the noise, since I like the sound signature of an early model 1 too much, and there's nothing out there that matches it precisely. MiSTer gets close but it's still not the same, and the triple bypass mod also sounds very good but is also a different sound.
Ikaruga11
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by Ikaruga11 »

Thanks.

So what about HDMI mods like the N64Digital, WiiDual, DCDigital, GCHD-MK II, etc.? Would the direct digital audio provided by those mods be noticeably better than the default analog audio output?

Another thing to consider are older surround sound formats like Dolby Pro Logic II, which was used on the Wii, GameCube, and even the N64. Basically, 4 channels of audio (left, right, center and surround) are all combined into 2 channel stereo audio and then seperated again when decoded by a receiver. Wouldn't there be a noticeable improvement in sound clarity if this was output digitally since there wouldn't be any analog interference between the four channels squeezed into two? With 4 channels being squeezed between two stereo analog outputs, I imagine there would be a lot of analog noise, distortion, and loss introduced for the surround sound mode. Digital would bypass this entirely.

So basically:

1) If the Audio Receiver has a better DAC than the console DAC, then sound quality will be better via digital than analog.
2) Digital audio won't lose sound quality from longer distances or poorly shielded cables, unlike analog audio.
3) No video/audio crosstalk with digital, preserving signal quality, unlike analog audio.
4) No analog buzz/hum/noise
5) No analog interference or loss between multiple channels on the same left/right audio channel, unlike with analog audio.
jamisonia
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by jamisonia »

Digital audio is almost always going to sound better, unless your receiver has a particularly terrible DAC. Whether you can hear the difference is a function of your audio setup and your ears.
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by darcagn »

Ikaruga11 wrote:Another thing to consider are older surround sound formats like Dolby Pro Logic II, which was used on the Wii, GameCube, and even the N64. Basically, 4 channels of audio (left, right, center and surround) are all combined into 2 channel stereo audio and then seperated again when decoded by a receiver. Wouldn't there be a noticeable improvement in sound clarity if this was output digitally since there wouldn't be any analog interference between the four channels squeezed into two? With 4 channels being squeezed between two stereo analog outputs, I imagine there would be a lot of analog noise, distortion, and loss introduced for the surround sound mode. Digital would bypass this entirely.
This shouldn't matter, either way you go it's 4 channels matrix-encoded into 2 with the receiver decoding it. I don't think decoding it before the DAC is applied would make a difference.

But your other conclusions are all correct. Personally I love 8-bit and 16-bit game tunes, and so I like to crank my video game music loud, which makes the slightest of analog noise noticeable. Whenever possible, I have done SPDIF and HDMI mods to my consoles.
jamisonia
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by jamisonia »

fernan1234 wrote:
So basically any system that has digital audio output will be a preferable choice, but coax analogue cables will be just as good in a speaker setup, ant the latter will also be good enough for pretty much any analogue out only system. The only exceptions I deal with are the NES, all of its models being buzz machines, and the unmodded Sega Genesis model 1, whose stereo output also has a very high noise floor.

.
OMG I thought I was alone on this. I spent the weekend pulling my hair out trying to lower the noise floor of the NES. I did have some luck lowering the buzz by forgoing the second 7805 in the NESRGB kit and instead installed a 78s05 (thought I've heard the original one is just fine for NESRGB, but I plan to use an Everdrive and 8bitdo so I wanted plenty of headroom). But its still pretty noticeable, especially on SMB 3 before you press start, when its silent. I also disconnected the original NES audio circuit by removing two resistors that it connects to after coming out of the CPU, and.... nothing. I was really surprised that didn't make a difference. Should mention I have my audio going to RCA jacks and I use Belden 1694a interconnects. Suffice to say that eliminates the buzzing coming from the cable run.

Next i'm going to try an Triad PSU, and failing that there is an open source power and AV module to replace the power/AV/RF module. I'm hopeful that maybe removing the RF components entirely might reduce the buzz, but honestly I'm starting to think the buzz comes out of the CPU itself.
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darcagn
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by darcagn »

jamisonia wrote:OMG I thought I was alone on this. I spent the weekend pulling my hair out trying to lower the noise floor of the NES. I did have some luck lowering the buzz by forgoing the second 7805 in the NESRGB kit and instead installed a 78s05 (thought I've heard the original one is just fine for NESRGB, but I plan to use an Everdrive and 8bitdo so I wanted plenty of headroom). But its still pretty noticeable, especially on SMB 3 before you press start, when its silent. I also disconnected the original NES audio circuit by removing two resistors that it connects to after coming out of the CPU, and.... nothing. I was really surprised that didn't make a difference. Should mention I have my audio going to RCA jacks and I use Belden 1694a interconnects. Suffice to say that eliminates the buzzing coming from the cable run.

Next i'm going to try an Triad PSU, and failing that there is an open source power and AV module to replace the power/AV/RF module. I'm hopeful that maybe removing the RF components entirely might reduce the buzz, but honestly I'm starting to think the buzz comes out of the CPU itself.
I've removed the RF components from my NES and replaced with Borti's power/AV module; unfortunately, this did not help. It's been years since I've messed with this but I tried everything I could and never could get rid of the buzz.
The Everdrive with expansion audio makes it significantly worse, and I installed a physical on/off switch on my Everdrive to disconnect the expansion audio circuit which reduces the buzz from the Everdrive cart, but that's about it.

These days I use MiSTer for NES gaming on my living room big screen though. The real NES is now only for the CRT in my office
fernan1234
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by fernan1234 »

jamisonia wrote:
OMG I thought I was alone on this. I spent the weekend pulling my hair out trying to lower the noise floor of the NES. I did have some luck lowering the buzz by forgoing the second 7805 in the NESRGB kit and instead installed a 78s05 (thought I've heard the original one is just fine for NESRGB, but I plan to use an Everdrive and 8bitdo so I wanted plenty of headroom). But its still pretty noticeable, especially on SMB 3 before you press start, when its silent. I also disconnected the original NES audio circuit by removing two resistors that it connects to after coming out of the CPU, and.... nothing. I was really surprised that didn't make a difference. Should mention I have my audio going to RCA jacks and I use Belden 1694a interconnects. Suffice to say that eliminates the buzzing coming from the cable run.

Next i'm going to try an Triad PSU, and failing that there is an open source power and AV module to replace the power/AV/RF module. I'm hopeful that maybe removing the RF components entirely might reduce the buzz, but honestly I'm starting to think the buzz comes out of the CPU itself.

Unfortunately none of that will work because the NES buzzing (that is not additional from poor cables, power supplies, etc.) comes from the PPU! This is why it varies depending on what is displayed on screen, and why in particular it's bad on the SMB3 as you noticed. If you have an Everdrive, just navigating through the menus and directories will let you hear the noise varying as well.

I'm pretty sure no one has figured out a way to get around this. A couple of years ago I read some speculation about a custom motherboard where the PPU sits in a different position. It would be interesting to compare an Opentendo or some other clone board that uses the original CPU and PPU. I used to have an old non-mini Analogue NT which was precisely this, and it still had the usual PPU buzz.
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Re: Digital HDMI Audio vs Analog BNC Coax Audio from RetroAc

Post by jamisonia »

Oh shit well that's good to know before I go spending all that money to chase it down, and this explains why nothing I did really seems to help.
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