Digital Audio A Possibility For Portables?

[Ampz]

If you know about the Gc video then you know that it has the capability
of providing digital audio through SPDIF cables.
So I wanted to know that if you get your GC video working with video in a portable then would
it be possible to fit digital audio into there as well using a digital audio amp?
Like this

What do you guys think?

 

[Ampz]

Re: Digital Audio?

Bumping, I really would like others opinions on this and if it's possible.

 

[Blargaman91]

But... why? The digital audio lines have always been there and we've had ways to use the signal but I don't think anyone want to put in the effort when you probably wouldn't even notice the effect. Digital audio is much more suited for theater systems with lots of speakers.

Edit: Actually, since digital signals shouldn't be susceptible to interference, which is a huge problem in portables, utilizing digital audio might provide audio without all that background noise.

 

[Ampz]

Hmm, I feel very excited about looking into this more, I never knew that as well, maybe this can be a solution to all that interference. It also doesn't seem like it'll be hard to implement digital audio into a portable. And if the digital audio amp that I've linked to can be trimmed down to a smaller size
then we might be onto something. Who knows?
I'll be looking more into this subject because of how interesting it is.

 

[Shank]

If you use, short ground shielded cables, interference shouldn't be a significant problem. If you take an unshielded wire, place it close to the regulators, and run a pre-amplifier signal through it, you are going to get quite a bit of noise.

Shielding wires makes a world of difference.

Digital out is optimal in circumstances where multiple channels need to run over long distances without interference. Since you will (presumably) only need stereo, and won't be running over large distance it seems unnecessary. Adding to that, you would need the hardware to code, send, receive, and decode the signal. It would wind up taking up more space and more power.

 

[Ampz]

Adding to that, you would need the hardware to code, send, receive, and decode the signal. It would wind up taking up more space and more power.

What you said about the hardware to send and receive and decode the signal. There's this PCB a member of Gc-forever has created called 'GC Video Lite' which he has programmed for to output analog rgb or component, however there is only a problem that most users encounter with the "DVI" version of it.
What has this got to do with the digital audio?
Well the PCB also has a contact which outputs digital audio for SPDIF.

here are some links:
The GitHub Repository
The Folder With The Readme About SPDIF

Audio

There are currently two options for the audio signal from the Gamecube when GCVideo Lite is used as the video encoder. The first option is to use the audio signals from the analog AV port as usual. The second option is to use the SPDIF encoder implemented in GCVideo Lite. The README.md of the gcvideo_lite HDL project has more information about connecting this signal - since it was added after the board was designed, no protection is present on the signal and a direct connection to an SPDIF input may destroy the FPGA.

Also sorry if this is what you were talking about, I wasn't entirely sure about what you
meant in your last sentence.

 

[Blargaman91]

If you use, short ground shielded cables, interference shouldn't be a significant problem.

Interference is created by regulators in most cases and sometimes other electronics. Lots of it is not airborne and is not easy to remove from the wires.

Ampz, the digital amp you linked is for 20 watt speakers, which are quite a lot bigger than any speakers you could fit into a portable. Most portable-sized speakers are 2 watts or fewer.

 

[Ampz]

Ampz, the digital amp you linked is for 20 watt speakers, which are quite a lot bigger than any speakers you could fit into a portable. Most portable-sized speakers are 2 watts or fewer.

Oh, thanks for reminding me i'll see if i'll be able to find a amp that is around 2 watts or less.

 

[Ampz]

Also, will 2.8W work or is a bit too big?
Edit: 3W or less?

 

[Blargaman91]

If it's a 3 watt speakers you can probably use 1.5 watt speakers or something bigger. Same goes for a 2 watt amp - 1 watt speakers will probably work.

 

[Shank]

The audio would need to be converted somehow at the cube to digital and somehow converted back to analog at the amp. I am unfamiliar with any methods to do so. I haven't looked into it at all. I don't know too much about the cube aside from its similarities to the Wii.

You want an amp that's capible of more than what you want. If you push an audio amp to its limits, it will distort.

Off topic for some perspective:
As for the 20 watt speakers, I played a show where I was running my ukulele through a 15 watt amp with a single speaker. The singer was mic'ed to the venues sound system, and my amp wasnt. I had my volume at 8 (out of 10) and people said they couldn't hear her because my amp drownwd her out. So yea. You won't need that much power unless you want to give everyone on your block the gift of final destinations theme music.
da. da-da-da. da. da-da-da. da-da-da.

 

[Ampz]

If it's a 3 watt speakers you can probably use 1.5 watt speakers or something bigger. Same goes for a 2 watt amp - 1 watt speakers will probably work.

Thanks Blargaman for the info

Off topic for some perspective:
As for the 20 watt speakers, I played a show where I was running my ukulele through a 15 watt amp with a single speaker. The singer was mic'ed to the venues sound system, and my amp wasnt. I had my volume at 8 (out of 10) and people said they couldn't hear her because my amp drownwd her out. So yea. You won't need that much power unless you want to give everyone on your block the gift of final destinations theme music.
da. da-da-da. da. da-da-da. da-da-da.

Dang, I certainly wouldn't want that because of where i'm living at the moment, i'm moving this week but still Dang.

 

[Blargaman91]

The audio would need to be converted somehow at the cube to digital and somehow converted back to analog at the amp.

The audio doesn't need to be converted to digital because, well it's already digital coming straight from the GPU, but it surely would have to go through some other conversions first. There are guides to attain SPDIF from a GameCube and it takes several ICs.

 

[Ampz]

Hopefully I can find a helpful guide.

EDIT: I remember a guide on GameSX, i've found it and the whole circuit itself is really small.

 

[Bush]

To add to what has been said, it's important to note (esp. with guitar amps) that 2W is not twice as powerful as 1W.

Watts |dB (rel to 1 watt)
1 |0
2 |3.01029996
5 |6.9897
10 |10
50 |16.9897
100 |20

Not only is 2.8W probably overkill power wise, it is also only a couple db louder ratger than being 2.8x as loud as a 1W. http://www.audioholics.com/frequent-que ... ts-and-dbs

I would use a 1W amp. Make sure your speakers are rated somewhat near, but above or equal to your amps power. If you powered 1W speakers with a 2.8W amp and cranked it up, the speakers would probably blow. No speaker you can reasonably fit in a portable will be much greater than 1W or so. The little drivers from cheap speakers and stuff like the iLuv all use 1W speakers.

Lastly keep impedance (8ohm, 4ohm etc) in mind, and if you hook up two speakers, you combine the wattage rating together. Your amp wattage needs to be below or equal to your speaker wattage or you will likely damage them. Even if they are rated the same, you can still damage your speakers if you crank the amp.

 

[Ampz]

Amazing! Thanks for the information Bush, I'll be sure to save this.