# Think about doing a Nexus 7 build



## jsteinm1 (Nov 3, 2012)

I'm thinking about doing a tablet build in my 2012 Ram 1500 using a Nexus 7. I have a library of MP3 audio I will load on to it...I would like to convert my CDs to FLAC for play back but I will run out of room unless theres a way to use a USB harddrive or something. What is the best way to output audio from the Nexus? I was thinking about using a Kenwood KDC-X996 so that I would have volume control and normal features. They have the Music Control app so I could USB.

I'd like to keep the budget for this around $500 if possible. I don't need anything thats audiophile grade, but I do want it to sound good.


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## Coppertone (Oct 4, 2011)

Ok, it's funny as I also have a Nexus7 laying around, and a 2011 Ram 1500. Subscribed as I am curious as to how this will play out.


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## jsteinm1 (Nov 3, 2012)

Google Nexus 7 in the Dash of Dodge Ram | Part 1 of 2 - YouTube

You've seen that video of one right? We have perfect dashes for it. They used an Audison Bit One for volume and dsp, but I think its a bit over kill to drive a $600+ dsp off of the 3.5mm from a tablet as they did. My thinking was to try out the Kenwood Music Control app so that I could retain my factory steering wheel controls over the system. I haven't tore anything apart yet, but it appears that I can relocate the buttons below the factory head unit to below the climate controls where theres a piece that says RAM. Then cut that hole out bigger to fit the Kenwood unit. I figure I will most likely use the Music control app to do audio over USB, but it will also do 3.5mm output or Bluetooth - whichever works out best with reasonable quality.


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## rekd0514 (Sep 24, 2006)

I am interested in replacing my CDA-9887 and using a Nexus 7 as well in my car. 

I am not sure what the best way to do that would be though. Would something like the Audison bit one or JBL MS-8 be the only way to hook up to your amplifiers and get good SQ from the Nexus?


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## CZ Eddie (Feb 26, 2012)

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## Orion525iT (Mar 6, 2011)

There are a few very good, relatively inexpensive usb DACs on the market that seem to work with Andriod despite the lack of true usb audio support (hopefully in the future that will change). There is one box that will even split a HDMI signal so that the usb port stays open. I know the nexus 7 does not have hdmi, but the nexus 4 does.

You don't get any eq or ta with these DACs, just high quality converstion. There is only one media player for andriod that I know of that has a parametric eq, and it is only 4 bands.

Of course the issue with the usb DACs is power consumption, but there may be a way to power them seperately.

Now if Canonical can get Ubuntu to share the Linux kernel with Andriod on Andriod devices like they plan to do, a ton of possibilities open up from there.

A year ago I would have thought car pc was the only option. But it seems now that handheld devices are finally packing enough compute power that the picture is radically different imo. Crazy that for the price of a fairly crappy low res touch screen for a car PC costs more than a full fledged tablet like the nexus 7 with cash to spare.


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## CZ Eddie (Feb 26, 2012)

Orion525iT said:


> There are a few very good, relatively inexpensive usb DACs on the market that seem to work with Andriod despite the lack of true usb audio support (hopefully in the future that will change).


This is the best Android DAC info thread I've been able to find. It has a continually updated listing of DAC's that work. _ NOT ALL DAC'S WORK_.
Hope it helps:

Android phones and USB DACs


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## rekd0514 (Sep 24, 2006)

Orion525iT said:


> There are a few very good, relatively inexpensive usb DACs on the market that seem to work with Andriod despite the lack of true usb audio support (hopefully in the future that will change). There is one box that will even split a HDMI signal so that the usb port stays open. I know the nexus 7 does not have hdmi, but the nexus 4 does.
> 
> You don't get any eq or ta with these DACs, just high quality converstion. There is only one media player for andriod that I know of that has a parametric eq, and it is only 4 bands.
> 
> ...


Good info. Thank you. I wonder how good a USB DAC like that would be SQ wise. I guess it doesn't matter if the N7 as a source has crappy output to being with. I'm sure certain phones/tablets have better audio outputs, but I would guess not much testing has been done. The audio chip they include with the phone is likely what decides whether it is any good.

It is pretty crazy what you get for $200 but they are also selling it at nearly cost to get people into the Google ecosystem. What could you do with linux/Ubuntu that you can't already with Android? XBMC is on android now as well and it seems it would be hard to beat a OS designed solely for touch on it. 



CZ Eddie said:


> This is the best Android DAC info thread I've been able to find. It has a continually updated listing of DAC's that work. _ NOT ALL DAC'S WORK_.
> Hope it helps:
> 
> Android phones and USB DACs


good link! My next question would be how would you get the DAC to your amps?


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## yoke (Nov 12, 2008)

Hi...I have try to post yesterday, but my post was want for administration, and now I don't see it...

any way...I'm planing to go with N7 for in dash installation ;
the plan :
- install N7
- use USB DAC
- use some bluetooth controller (as wii controler), connected to steering wheel controls, to control media player N7
- use online radio streaming instead of FM receiver, via wifi connected to my phone
(nexus don't have FM radio, and as I know there is no FM receiver usb dodge for it. I have no plan of buing 3G version of N7, so will use my mobile phone as wifi spot, and connect N7 to it)
- use external storage, as HDD or external microSD, or similar for music

operation
- when ignition key is OFF, N7 goest to sleep, turns off wifi,bluetooth...while in sleep it use N7 battery
- when ignition is ON, N7 is up and turns on wifi, bluetooth...it's on charger

The charger is connected all the time, but will start with ignition, and goes of with ignition off.

To have it install this way you have to do software modifications as nexus7 doesn't support USB DAC from the box, and charging while there's external USB conection.

Here is the link where you can find software;
http://rootzwiki.com/topic/37755-timurs-kernel-robust-usb-host-power-management/

And there is solution how to control USB DAC volume via N7, but don't know is it implemented inside timurs karnel, if not I hope it will be soon...if not, then I will have to place some volume control after USB DAC analog out ;
http://rootzwiki.com/topic/37176-mod-cm10-usb-audio-support/

p.s. sorry for bad english, but I think you get the picture


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## Hdale85 (Jan 21, 2012)

If you use a USB DAC or USB to I2S/SPDIF device it shouldn't matter what the N7's output is. I'm thinking about going this route and you CAN hook up an external hard drive to a Nexus 7, and you can use USB audio devices. So I'm thinking getting I2S or SPDIF out via USB and into a MiniDSP or something would be ideal. Or any other high end processor that accepts a digital input. My only concern is will it do both the DAC and the external hard drive at the same time?

By the way I think to use external hard drives and USB sound cards you need to root the device.


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## rekd0514 (Sep 24, 2006)

Hdale85 said:


> If you use a USB DAC or USB to I2S/SPDIF device it shouldn't matter what the N7's output is. I'm thinking about going this route and you CAN hook up an external hard drive to a Nexus 7, and you can use USB audio devices. So I'm thinking getting I2S or SPDIF out via USB and into a MiniDSP or something would be ideal. Or any other high end processor that accepts a digital input. My only concern is will it do both the DAC and the external hard drive at the same time?
> 
> By the way I think to use external hard drives and USB sound cards you need to root the device.


You should be able to to this with a USB OTG cable and a USB hub. You will need root and this kernel. 

Timur's Kernel - USB ROM - USB Host Power Management - USB Audio - Nexus 7 Development - RootzWiki


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## Hdale85 (Jan 21, 2012)

Awesome, I'm still not sure I want to go with a tablet, I may just grab one of these mini android PC's and build it around that. Something like this

ODROID | Hardkernel


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## naiku (May 28, 2008)

I am fairly certain that I am going to attempt a Nexus 7 install in my car. The OEM head unit, while it works, stinks. To upgrade to aftermarket I would have to spend around $150-$200 on wiring harness, so while browsing around the other day I came across a tablet install. 

Next thing you know I am holding my wifes Kindle Fire up to the dash and checking for fitment. I already have an MS8, so plan to use the aux input available on that. I plan to tether it to my phone for streaming music, but also pick up an external hard drive as well. Debating picking up a dock for it and mounting that in the dash, but from the reviews I have read the dock is a POS. 

The one good thing about the dock is it appears to make it easier to connect USB devices, as the USB port on the Nexus itself is not used by the charger. The other piece I read (but cannot confirm) is that using the 3.5mm output on the dock is about half the volume of using it on the tablet itself. 

Hopefully I can pick up a tablet in the next few weeks and start to play about with it some.


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## Hdale85 (Jan 21, 2012)

I guess if you root the Nexus 7 and install a USB chain rom you can use an OTG cable and a HUB and charge and use USB at the same time. If I went with a Nexus 7 I think I'd definitely be using a USB device to get digital output. Although I guess the MS8 doesn't have a digital input does it? I can't remember I had one for a short time but never installed it.


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## naiku (May 28, 2008)

Hdale85 said:


> I guess if you root the Nexus 7 and install a USB chain rom you can use an OTG cable and a HUB and charge and use USB at the same time.


For storage I am actually looking at one of the Seagate Wireless drives. Which somewhat negates the need to use the OTG cable / Hub. The dock would be neat though for ease of removal/installation.



Hdale85 said:


> Although I guess the MS8 doesn't have a digital input does it? I can't remember I had one for a short time but never installed it.


Correct, no digital input on the MS8. there was some talk of modding an input onto one, but it went nowhere (would also be way above my head as to how to mod that anyway).

Edit: Test fitted my wife's Kindle fire in the dash... 










Looks to fit nicely, just have to fabricate a bezel out of something and figure out a way to securely mount it in there.


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## Orion525iT (Mar 6, 2011)

One of those boards above uses the same Wolfson dac as my Note II. But, the dac is one thing and the implementation is another. After some delays with my car pc, I always found the lack of decent monitors to be extremely frustrating. So when my ancient my touch slide phone fell apart I upgraded big to the Note II. My plan was to use an external dac and maybe a mini dsp. After I had the phone I realized that the audio output was very nice. I then started to research and found that it had a Wolfson DAC. Embarrassingly I had no idea before the purchase. I am actually very pleased with the sq, running the phone directly into the amp.

So now I have an excellent display (still a bit small at 5.5"), with a good DAC all in one device.

The biggest draw backs of andriod devices are lack of storage space, and the lack of decent audio players. My phone has a removable memory card slot up to 64g with 8g onboard. Many tablets lack the micro SD slot. Unfortunately the nexus 7 also does not have microsd. There are some audiophile players, like Neutron player. Neutron has a 4 band parametric eq. My stock player has a 7 band eq. If I need more bands or additional processing ability, the mini dsp is still an option...but a PC is required for tune and programming. But the pc can be eliminated once everything is set up

As far as I know, the DAC in the mini dsp does not work with andriod. Many DACs will work with my phone and should work with nexus 7 without rooting. Some moded kernels claim to be able to use the DAC better and increase output at the 3.5 jack.

Head-fi.org has a bunch of good info on andriod and external DACs. Some of the DACs know to work well also operate off seperate battery packs. This can help with the electrical load put on the andriod device. Both the phone/tablets and battery powered DACs have the advantage of very clean electrical input. The disadvantage of course is that they both need charging.


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## Hdale85 (Jan 21, 2012)

Well even if the USB module for the MiniDSP doesn't work, you can get a USB to Optical/SPDIF out and feed it into the MiniDSP, or just use a USB dac and feed it in.


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## naiku (May 28, 2008)

Picked up a nexus today, removed OEM head unit and ran 3.5mm to RCA cable to the trunk.


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