# USB Audio Request



## jmcguire525 (Jul 13, 2012)

From everything I've read N7 will ship with google proprietary USB audio, meaning the tablet is seen as the client and will not work with a USB DAC. Are any devs planning to or willing to enable standard USB audio on the Nexus 7?


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## jmcguire525 (Jul 13, 2012)

Anyone? I'm willing to donate $50 to any dev that can put this feature in a kernel for the Nexus 7.... I plan on using this as a head unit in my car USB -> USB/Toslink -> Audison BitOne -> Audison Voce 5.1k . Digital audio will run all the way to the amp and I am hoping to use the pogo pins to extract the digital audio. Also is there a way to charge and use usb audio at the same time (maybe someone with a SIII will know)


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## TRE_588 (Jun 6, 2011)

why not just use bluetooth? N7 ->Hu or N7->usb->bluetooth dongle wouldn't that work?


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## jmcguire525 (Jul 13, 2012)

If bluetooth was able to send lossless audio I would, I want I am aiming to keep everything digital throughout the Audison system.


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## padraic (Jul 21, 2011)

lossless in the car? you must really have golden ears.

Sent from my ADR6400L using Tapatalk 2


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## nhat (Aug 21, 2011)

Or a car stuffed with sound deadening. I'd rather have less weight in my car than lossless sound and worse MPGs.

I really don't understand people's obsession with lossless music on their phones and in the car. At home? Sure, that makes perfect sense if you've got tube amps and high-end speakers.


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## jmcguire525 (Jul 13, 2012)

It's not just about having lossless audio, I don't have to worry about bluetooth pairing problems, the whole installation and setup are much easier when the whole chain is digital, all I have to do is slide the tablet into place touching to pogo pins and i'm good to go


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## arigold (Jul 18, 2012)

jmcguire525 said:


> It's not just about having lossless audio, I don't have to worry about bluetooth pairing problems, the whole installation and setup are much easier when the whole chain is digital, all I have to do is slide the tablet into place touching to pogo pins and i'm good to go


jmcguire525: Are you aware that USB audio can only reproduce 48kHz? I wouldn't expect 192, and with a Bit One USB may be underkill for your setup. Have you thought about building a cheapish car PC with a motherboard that does digital audio out? Then you can use your Bluetooth to do a Remote Desktop via Splashtop to control the car PC? At least, that's my plan...Let me know what you think!


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## jmcguire525 (Jul 13, 2012)

Yes I am, check out this article http://people.xiph.org/~xiphmont/demo/neil-young.html , and yeah the BitOne is overkill but I am getting a deal on the complete setup from someone that barely used it.


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## number5toad (Sep 13, 2011)

great read, thanks for sharing - next time one of my coworkers gives me crap for recording at 24 bits, OR one of my friends gives me crap for preferring flac, I'm just gonna make 'em check this out.


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## jmcguire525 (Jul 13, 2012)

Welcome, and again if anyone is willing to add standard usb audio out to a kernel I will gladly pay to help make it happen. I know the S3 already has this feature and it would be amazing to have it working through the pogo pins on the N7


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## JBirdVegas (Jun 11, 2011)

jmcguire525 said:


> Welcome, and again if anyone is willing to add standard usb audio out to a kernel I will gladly pay to help make it happen. I know the S3 already has this feature and it would be amazing to have it working through the pogo pins on the N7


Try contacting the one who wrote said patch and offer them the reward for posting a nexus7 kernel patch

Or ask a kernel Dev, but I would do the legwork before I approached anyone...

Find kernel Dev with said feature
Find path to feature in source
Use git blame (Github feature) to find the latest changes to those lines
Then approach a pro with all this background... I bet then you find your pot of gold, don't just assume anyone else wants to do the legwork.


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## jmcguire525 (Jul 13, 2012)

Thanks JBird, I'll have to start doing my homework and look around, the S3 comes stock with this feature if anyone knows of a kernel patch that was added to another device for standard USB audio to get me on the right track I'd appreciate that!


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## Art Vandelay (Jan 4, 2012)

Really the S3 has this feature stock, why has this not been implemented in to the GNex. I thought JB was suppose to have this feature included.

Don't have a N7, but interested to see where this goes since I want it for my GNex.

Sent from my Galaxy Nexus using RootzWiki


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## jmcguire525 (Jul 13, 2012)

Yep, the S3 works as a host allowing most DACs to work stock, the new USB audio in Jellybean acts as a client and requires a new type of DAC. I am going to try to do more research tomorrow on how to bring this functionality over to nexus devices but I have no experiences with kernels or code. I'll do what I can to make this happen but I'd really like to find a dev willing to help out. Am I the only one that thinks this is a killer $200 head unit for a car, USB audio from the pogo pins and all you have to do in slide it into the dash. You can pay someone to make you a custom mount inside the dash to replace a double din head unit and still come out cheaper than most quality head units!


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## JBirdVegas (Jun 11, 2011)

jmcguire525 said:


> Yep, the S3 works as a host allowing most DACs to work stock, the new USB audio in Jellybean acts as a client and requires a new type of DAC. I am going to try to do more research tomorrow on how to bring this functionality over to nexus devices but I have no experiences with kernels or code. I'll do what I can to make this happen but I'd really like to find a dev willing to help out. Am I the only one that thinks this is a killer $200 head unit for a car, USB audio from the pogo pins and all you have to do in slide it into the dash. You can pay someone to make you a custom mount inside the dash to replace a double din head unit and still come out cheaper than most quality head units!


You may have a business plan not a feature request, do more background and let me in on the alpha testing :-D

Love it but how do you make it work?


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## jmcguire525 (Jul 13, 2012)

got a kernel to try out thanks to Poitee, ill report back as soon as I can!


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## jmcguire525 (Jul 13, 2012)

Thanks Poitee! This is working in his V3 kernel, no switching yet so everything has to be plugged in before booting and when you unplug there is no audio from the tablet.


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## arigold (Jul 18, 2012)

Wow, GOOOD. Now, just find a time alignment app, and we're all set!


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## dcplaya (Jun 9, 2011)

jmcguire525 said:


> Thanks Poitee! This is working in his V3 kernel, no switching yet so everything has to be plugged in before booting and when you unplug there is no audio from the tablet.


What adapter is that? How are you converting USB to audio out? The video is too blurry for me to make it out

Edit: Also, can this work through a USB hub as well as have a ADK device (Arduino) talking to the N7 as well?


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## jmcguire525 (Jul 13, 2012)

I am using an usb otg cable and advantage micro 2 sound card, it is working with Poitee's V3 kernel but only when everything is connected before booting the device.


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## davidasc22 (Dec 27, 2011)

jmcguire525, I'm in the same boat. I'm trying to get my tablet or phone to work with my alpine unit so i can use spotify rather than use my ipod. No luck so far.


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## dcplaya (Jun 9, 2011)

jmcguire525 said:


> I am using an usb otg cable and advantage micro 2 sound card, it is working with Poitee's V3 kernel but only when everything is connected before booting the device.


Is there any way you can charge the tablet while using USB OTG?


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## Sengir (Sep 17, 2012)

dcplaya said:


> Is there any way you can charge the tablet while using USB OTG?


Currently not..What a shame..


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## PaulF (Sep 23, 2012)

First of all, great project. I'm working on a very similar project - microcontroller automation of the car, nexus 7 for a head unit, and USB audio. I've been building car pc's for years and I'm finally convinced that I can achieve much more, much more cheaply, with an android tablet.

Any chance I can get my hands on this kernel/the knowledge required to compile it? I'm also willing to post some bounty.

As a software developer, I'm curious how much work it will be to implement switching audio sources. I'm assuming that that is at the android level, not the kernel level. Is Poitee working on that, or only on the kernel?

On the topic of the OTG port...


dcplaya said:


> Edit: Also, can this work through a USB hub as well as have a ADK device (Arduino) talking to the N7 as well?


On the topic of the USB hub, yes this is totally possible. Once the USB port is a host usb port, all USB devices supported by the linux kernel on your android device will work - but you need to compile your kernel with the correct drivers for audio, and write the apps that know how to use them. I'm currently using my nexus 7 with a usb hub, an arduino, and a flash drive attached with no issues.


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## tb7andro (Dec 16, 2011)

If you don't mind my asking, I received a arduino uno, and was wondering what you're using yours for? Connected to android and all

Sent from my Full Android on Grouper using RootzWiki


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## JackNorris (Nov 24, 2012)

For those of you wanting USB audio support without rebooting, give this a try.

http://rootzwiki.com/topic/37176-mod-cm10-usb-audio-support/


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