Pyra audio connector/jack-related questions


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Forgive me if these questions somehow fall under the "sure, if somebody codes it in" response, but I was curious, the 3.5mm jack on the Pyra is, according to the wiki, TRRS with automatic switch to go from OMTP to CTIA. Now, in the case of in-line remotes(with mic) for a headphone cable, would this allow for compatibility with the apple-compatible 3-button remotes(volume -/+ & center button) or just the single button android-style ones (because as I understand it, apple does its own crazy voodoo..)? Also, would/could either one be used in the standard Pyra desktop Linux(like with a Linux desktop phone program and/or with music & movies, on Linux desktop, I'd ask about re-mapping the remote's button functions, but that sounds likely to be a software issue), could the Pyra somehow force android(if installed) to use apple 3-button in-line remotes?

semi-related bonus question: As some TRRS setups allow for video to be sent(or is it received?) along one of the TRRS segments, could the Pyra do that as well?

*One last question, I'd be really interested to learn if the Pyra will output balanced audio through the TRRS jack.*

Thank you very much for putting up with my questions.
from: Paul
 

levi

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As far as I know, all of these extra buttons on headphone remotes work by multiplexing the old single button. The single button works by shorting microphone and ground, and the extra buttons work basically by sending something like morse code over this on-off switch. So yes, I'm afraid it'll depend on someone finding or writing the code to decode those signals.

The Pyra could send video on one of the rings, but I don't really see the point. You'd only get composite output that way, and the Pyra should have a working HDMI socket which you can hook up to a 1080p display just fine.

I doubt the Pyra hardware could produce balanced audio - there's two channel output and only one ground. What would be balanced against what? Also, it needs to support headphones which can have relatively high impedances, which I suspect excludes it being wired for balanced, but I don't really understand the topic well enough to be definitive on that. But you could split the ground and then wire each pair up separately to appropriate baluns, if you really wanted balanced analogue audio, but I suspect it may be simpler and more cost effective (at least in terms of your time and sanity) just to buy a box that splits the audio off the HDMI connection in the way you want, or even a compatible USB soundcard with the right capacity.
 

Silent-Hunter

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The Pyra could send video on one of the rings, but I don't really see the point. You'd only get composite output that way, and the Pyra should have a working HDMI socket which you can hook up to a 1080p display just fine.
Some people need to be able to output composite, my parents TV is from the early 80s and I would love to be able to display things on their TV, would the Pyra really be able to do that?
 

Eight Bit

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*One last question, I'd be really interested to learn if the Pyra will output balanced audio through the TRRS jack.*


I think the Pyra could output balanced audio just fine; Make mono, phase reverse the audio signal on the 2nd channel and cap the max voltage (output volume). Nothing that can't be done in ALSA I think?
It will cost you your 2nd channel but hey, Stereo is over-rated anyway.

Oh shit... Afterthought: If/when converted to XLR, there's the possibility that there's 48v phantom power on the line fed by a mixer.
My guess is Pyra's audio output might not like that. Better to carry a DI box then.

Damn, and I was already imagining making a small mini jack to XLR cable as it would be great for line testing on stage :)
 

WizardStan

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The devices that do video over TRRS have it connected to the video port via hardware, no such connection exists in the Pyra as far as I'm aware. In order to send or receive video through the TRRS port it'd have to be converted to "audio" where every pixel is a played as a sound sample through the audio chip, and I'm pretty sure it will be capable of producing or recording at most 192khz (though just 96khz is far more likely), and even if it can get ultra high quality audio at 384khz it's still is a far cry from the approximately 30Mhz required by a 480p video stream.
[doublepost=1481715415,1481715187][/doublepost]
The single button works by shorting microphone and ground, and the extra buttons work basically by sending something like morse code over this on-off switch.
It can short through different resistors and multiplex that way: a 1k resistor for play/pause, a 2k resistor for forward, 4k resistor for back, etc... and each resistor value produces a different "level" on the microphone. Much easier than simply pulsing on/off, just check what "tone" the "microphone" is "hearing".
It would still need someone to code it like you say, obviously.
 

Letalis Sonus

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Didn't the IC that's responsible for detecting and switching the order of contacts for headsets actually support detecting such buttons? I remember readings something like that, supporting those buttons could be easy...
 

Kev2442

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42 (Loire) is the answer.
If/when converted to XLR, there's the possibility that there's 48v phantom power on the line fed by a mixer.
My guess is Pyra's audio output might not like that.

Most Phantom Power-enabled devices have a switch allowing it to use XLR devices with or without it. XLR isn't solely used with static mics, though they most commonly are. That's why many audio interfaces don't output 48V on every XLR input.
Then what about input : could the Pyra power this kind of microphones ? That would be great for recording on-the-go, even if for that, I'd still rather carry my Roland UA-55 Quad-Capture with me. (if you're looking for a budget 192KHz audio interface, this one is just great)
 

Grench

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Given that the cord lengths we're talking about are more like 2m than 200m, unbalanced audio should be just fine from the Pyra into the unbalanced jacks on the mixer. Balanced audio and XLR cables become relevant when you're dealing in long lines. Within arms reach is not a long line.
 

Letalis Sonus

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I'm just waiting for the day I accidentally hit that switch on my sound card with my knee, grilling my headset - a push button whose position can't be recognized on first glance without any status LED is a bad design decision...
 
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If/when converted to XLR, there's the possibility that there's 48v phantom power on the line fed by a mixer.
My guess is Pyra's audio output might not like that.
Most Phantom Power-enabled devices have a switch allowing it to use XLR devices with or without it. XLR isn't solely used with static mics, though they most commonly are. That's why many audio interfaces don't output 48V on every XLR input.
Then what about input : could the Pyra power this kind of microphones ? That would be great for recording on-the-go, even if for that, I'd still rather carry my Roland UA-55 Quad-Capture with me. (if you're looking for a budget 192KHz audio interface, this one is just great)
Being able to use XLR mics with the Pyra would be one thing(and pretty cool; also, there are XLR-to-usb adapters, Shure makes one of them), but I was more wondering about something like a standard 3.5mm TRRS terminated stereo audio cable. As I understand it (though I do realize I could be wrong), they should be able to carry balanced audio, and as the Pyra is supposed to come equipped with a 3.5mm TRRS jack..

for some reason, to get the quotes in this reply post to show up like that I had to copy both separately, then intertwine them together..
 
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TrashyMG

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@levi I believe that works the reverse of what you think it does.

This is what you want:
 

Eight Bit

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Being able to use XLR mics with the Pyra would be one thing(and pretty cool; also, there are XLR-to-usb adapters, Shure makes one of them), but I was more wondering about something like a standard 3.5mm TRRS terminated stereo audio cable. As I understand it (though I do realize I could be wrong), they should be able to carry balanced audio, and as the Pyra is supposed to come equipped with a 3.5mm TRRS jack..

Of course it can, regular balanced audio connectors are just TRS, on the pyra you would have an extra ring for the microphone or return line. Like I mentioned before you would only need some audio processing and a custom made cable. Standard stereo cables aren't wound around each other so one side could pick up more interference than the other, eliminating some of the profits of balanced audio.


XLR 1. Gnd - Sleeve
XLR 2. Hot - Tip
XLR 3. Cold - Ring
 

Neelix

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I wish Evildragon would turn that off again. There's no need to embed amazon links, and in addition to not working with ad-blockers I have to say it looks ugly to boot.

-Neelix
 
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Of course it can, regular balanced audio connectors are just TRS, on the pyra you would have an extra ring for the microphone or return line. Like I mentioned before you would only need some audio processing and a custom made cable. Standard stereo cables aren't wound around each other so one side could pick up more interference than the other, eliminating some of the profits of balanced audio.


XLR 1. Gnd - Sleeve
XLR 2. Hot - Tip
XLR 3. Cold - Ring

Forgive me if I'm just not getting it, but you seemed to be talking about balanced mono, I was wondering about balanced stereo(does it even exist?).

..or would blanced stereo not work on a TRRS, would that require TRRRS?
 
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