Android 5.1 head unit >>> USB Audio (DAC) output

[DanB0y]

Hi, I installed a MTCD Android head unit with Android 5.1.1 in my car two weeks ago. (I could'nt start this thread in the MTCD section because I'm new here)

My car audio setup goes as follow: Android Head Unit >>> USB Cable >>> PCM2704 USB to SPDIF adapter >>> SPDIF coax cable >>> MiniDSP 6x8 >>> 3 Amps >>> Speakers + sub.

So far I've been able to get SPDIF sound output with Neutron (Direct USB mode), Onkyo HF Player, USB Audio Player Pro, HibyMusic Player.
Sound is amazing btw.
If I understand correctly, all these apps are working with the USB DAC because they use their own app's USB Driver.

Important to know: All song in 44khz are playing fine, songs in 48khz makes every app freeze. I got a way around this by setting Neutron to resample every song in 44khz, so all songs are working now.

Now, if I play a song in Google Play Music, Spotify, Kodi, etc no sound comes out ... same thing for my HU video app, phone calls etc.

Is there a way around this ? What modifications can be made so every sound outputs to the USB Audio ? IE. kernel update, system files modifications etc ??

Thanks for any input.

 

[DanB0y]

Nobody use a USB DAC with his head unit ?

I have found this thread: http://forum.xda-developers.com/showpost.php?p=66707293&postcount=47

But I dont think it applies to Android 5.1, sound management is different.

 

[CadillacMike]

i dont use any DAC on this head unit. But I do have a Dragonfly USB DAC on my computer. the Dragonfly Red says it works with Android. Not sure if that is just marketing, or if it doesn't something specific.

 

[DanB0y]

i dont use any DAC on this head unit. But I do have a Dragonfly USB DAC on my computer. the Dragonfly Red says it works with Android. Not sure if that is just marketing, or if it doesn't something specific.

Can you try it please ?

 

[CadillacMike]

Can you try it please ?

i dont know how I would even go about hooking it up? i could plug it into the USB port, but then what? use headphones?

all my speakers go through the wiring harness

 

[Hisma]

i dont know how I would even go about hooking it up? i could plug it into the USB port, but then what? use headphones?

all my speakers go through the wiring harness

you would need to be using pre-outs, using a 3.5mm to rca cable into an external amp.

---------- Post added at 09:03 AM ---------- Previous post was at 08:57 AM ----------

interesting that you've tried this. This forces you to completely by-pass the HUs sound processing.

I have the same DSP, but I'm using direct pre-outs. I like this idea though bc it gets around the low pre-out voltage, and allows you to ignore the poorly implemented sound processing in the HU.

Unfortunately, you probably need to modify the filesystem to get this to work, as your link shows. Why do you feel the need to use a DAC in addition to the DSP?

 

[CadillacMike]

you would need to be using pre-outs, using a 3.5mm to rca cable into an external amp.

my sub is tapped into my speaker wires, so I dont use the RCA preouts. So I probably can't try this.

However, I think my audio is pretty great with the Joying

 

[DanB0y]

i dont know how I would even go about hooking it up? i could plug it into the USB port, but then what? use headphones?

all my speakers go through the wiring harness

Yes simply use headphones
We just need to know if audio is outputing from the DAC.

I would appreciate, thanks !

 

[DanB0y]

Unfortunately, you probably need to modify the filesystem to get this to work, as your link shows. Why do you feel the need to use a DAC in addition to the DSP?

The DAC is a really clean source signal VS the head unit, I have a 2000$+ sound system in my car and sound quality is very important to me.
Also, DAC is digital signal VS analog RCA outputs on the head unit.

 

[Hisma]

The DAC is a really clean source signal VS the head unit, I have a 2000$+ sound system in my car and sound quality is very important to me.
Also, DAC is digital signal VS analog RCA outputs on the head unit.

I agree. I feel like right now my HU is the "weak point" of my system. I am about the same as you, roughly $2000 in equipment (probably a little more).

focal KRX3 3-way active system w/ a cheap kicker sub + 3 amps. I have the C-DSP along w/ a line driver to manage the low pre-out voltage. Would love to take the line driver out of the signal chain if I could. All these components are taking up a lot of valuable space.

I hope you figure this out. I don't have a MTCD, I have a non-joying 4.4 HU. Would love to use the SPDIF inputs on the C-DSP as opposed to the ****ty pre-outs from the HU.

 

[DanB0y]

I agree. I feel like right now my HU is the "weak point" of my system. I am about the same as you, roughly $2000 in equipment (probably a little more).

focal KRX3 3-way active system w/ a cheap kicker sub + 3 amps. I have the C-DSP along w/ a line driver to manage the low pre-out voltage. Would love to take the line driver out of the signal chain if I could. All these components are taking up a lot of valuable space.

I hope you figure this out. I don't have a MTCD, I have a non-joying 4.4 HU. Would love to use the SPDIF inputs on the C-DSP as opposed to the ****ty pre-outs from the HU.

Nice ! I have 3 way peerless (tweets + 3.5 mids + 7in woofer) 1 pioneer amp 4ch for tweets + mids and 1 pioneer amp 2ch for the woofers, another JBL amp in the trunk with a 15in Alpine Type-R. I have the C-DSP 6X8 MiniDSp as well

 

[DanB0y]

SPDIF to C-DSP SPDIF Input would give you 4V at the MiniDSP RCA outputs

 

[Hisma]

SPDIF to C-DSP SPDIF Input would give you 4V at the MiniDSP RCA outputs

well you have convinced me to give this a shot. The USB DAC + 25 ft coax cable only set me back $35 on amazon. So even if this doesn't work I won't be mad.

The potential for 4V of CLEAN pre-out voltage is too enticing to pass up. The line driver works, but like I said it's another box that needs power/space/etc. The USB DAC also allows me to take the HU sound processor fully out of my signal chain.

I am unfortunately using android 4.4, so dont think I can help you much, but I will let you know if this works nonetheless.

 

[DanB0y]

well you have convinced me to give this a shot. The USB DAC + 25 ft coax cable only set me back $35 on amazon. So even if this doesn't work I won't be mad.

The potential for 4V of CLEAN pre-out voltage is too enticing to pass up. The line driver works, but like I said it's another box that needs power/space/etc. The USB DAC also allows me to take the HU sound processor fully out of my signal chain.

I am unfortunately using android 4.4, so dont think I can help you much, but I will let you know if this works nonetheless.

If it dont work natively, I'm 99% sure it will work with the Neutron music player. Install it and then go to hardware settings and enable Direct USB Driver. :good:

 

[Hisma]

If it dont work natively, I'm 99% sure it will work with the Neutron music player. Install it and then go to hardware settings and enable Direct USB Driver. :good:

well I tested this today and I am very pleased with the results. I really do notice a difference in SQ. It sounds "cleaner" and fuller.

Only major thing I notice is the overall volume seems really high over SPDIF. Only place I can adjust the volume now is with the DSP, but even then, I find I need to turn the gain down on the SPDIF inputs to get an acceptable volume. This is even with gain all the way down on my amps. This leads to a bit of clipping on the highs.

Did you make any adjustments in neutron player or the DSP to get an acceptable volume? Or do you get by with just adjusting the DSP master volume?

Now I just need to see if I can get all my sound to route through. I like to listen to streaming music too but I don't think I can go back to using analog pre-outs.

 

[DanB0y]

well I tested this today and I am very pleased with the results. I really do notice a difference in SQ. It sounds "cleaner" and fuller.

Only major thing I notice is the overall volume seems really high over SPDIF. Only place I can adjust the volume now is with the DSP, but even then, I find I need to turn the gain down on the SPDIF inputs to get an acceptable volume. This is even with gain all the way down on my amps. This leads to a bit of clipping on the highs.

Did you make any adjustments in neutron player or the DSP to get an acceptable volume? Or do you get by with just adjusting the DSP master volume?

Now I just need to see if I can get all my sound to route through. I like to listen to streaming music too but I don't think I can go back to using analog pre-outs.

Great ! Now you're in the same boat as me lol
(Except for the clipping, I have no problem with that)

What is the model of your amps ? I have my gain to around 1/3 in the amps (They're up to 6.5V input sensitivity) and spdif input gain is at 0.

For your sound routing, you can sum the rca inputs and the spdif input together in the DSP And then you use your input levels to match the loudness. That way, you'll be able to listen excellent SQ music from Neutron and still hear BT phone calls, Youtube, navigation etc trough the analog inputs.

 

[Hisma]

Great ! Now you're in the same boat as me lol
(Except for the clipping, I have no problem with that)

What is the model of your amps ? I have my gain to around 1/3 in the amps (They're up to 6.5V input sensitivity) and spdif input gain is at 0.

For your sound routing, you can sum the rca inputs and the spdif input together in the DSP And then you use your input levels to match the loudness. That way, you'll be able to listen excellent SQ music from Neutron and still hear BT phone calls, Youtube, navigation etc trough the analog inputs.

Yes! This is exactly what I have done. I spoke too soon also. The clipping was more a tuning issue than anything (changed cross-over on tweeters & lowered their output a bit). I was able to set the gain on SPDIF back to 0.

Man it sounds really good now. I haven't any real tuning yet outside of setting gains and cross-overs. I think once I tune the system it'll take it over the top.

I have a mosconi as100.4 on the tweeters and mids, and a alpine mrv-m500 on the sub. (i have one other amp I am replacing to power mid woofer, should arrive tomorrow). It's a total overkill system, but I find great deals on used gear on diymobileaudio classifieds so I keep upgrading lol.

So now I will use neutron for majority of listening, and by mixing channels together on the analogs I already had connected, I get acceptable SQ for phone calls and streaming music. I have no desire to mod my system files the way it was shown in that thread you linked. Looks too risky. I am okay with this new arrangement since 90+% of my listening is my personal music collection.

Really appreciate you making this thread. I always knew my system was capable of sounding better and this did the trick. I will let you know if I figure anything else out that could be useful.

 

[DanB0y]

Yes! This is exactly what I have done. I spoke too soon also. The clipping was more a tuning issue than anything (changed cross-over on tweeters & lowered their output a bit). I was able to set the gain on SPDIF back to 0.

Man it sounds really good now. I haven't any real tuning yet outside of setting gains and cross-overs. I think once I tune the system it'll take it over the top.

I have a mosconi as100.4 on the tweeters and mids, and a alpine mrv-m500 on the sub. (i have one other amp I am replacing to power mid woofer, should arrive tomorrow). It's a total overkill system, but I find great deals on used gear on diymobileaudio classifieds so I keep upgrading lol.

So now I will use neutron for majority of listening, and by mixing channels together on the analogs I already had connected, I get acceptable SQ for phone calls and streaming music. I have no desire to mod my system files the way it was shown in that thread you linked. Looks too risky. I am okay with this new arrangement since 90+% of my listening is my personal music collection.

Really appreciate you making this thread. I always knew my system was capable of sounding better and this did the trick. I will let you know if I figure anything else out that could be useful.

Yeah I know what overkill sounds like haha
For frontstage 3way I got a 4ch Pioneer Premier PRS-X340 running 2x NE25-VTS04 Peerless tweets and 2x NE95W-04 3in Peerless mids, another Pioneer old scholl amp pushing 2x175w for 7in Wavecor woofers. In the trunk is a JBL GTO14001, 1500Wrms @2ohm pushing a 15In Alpine Type-R sub in 3.5cuft tuned @21hz

All my amps are very good condition used gear found on classifieds too, you can dig some real treasors for very little money sometimes !

I've been looking all around the web since last week for how to route every sounds of the HU to a USB DAC, translating and reading about 500 pages worth of XDA/Russian Android forums, spent last nights editing config files all around my HU System folder, I tried the how-to link I posted in OP for MTCB units, nothing to do.. I really think the Kernel must be enabled for USB Audio for it to work, my DAC shows up in USB devices info but not in the audio output devices.

Well, I'm still happy because my FLAC music collection plays incredibly well i dont car that much for FM Radio SQ, I only wish I'd be able to listen to Spotify or Kodi on the DAC.

Im r eally glad if I could be any help to you and will keep this thread updated if I find something !

 

[modream]

navigation guidance voice goes through usb audio ?

 

[frankienones]

Yeah I know what overkill sounds like haha
For frontstage 3way I got a 4ch Pioneer Premier PRS-X340 running 2x NE25-VTS04 Peerless tweets and 2x NE95W-04 3in Peerless mids, another Pioneer old scholl amp pushing 2x175w for 7in Wavecor woofers. In the trunk is a JBL GTO14001, 1500Wrms @2ohm pushing a 15In Alpine Type-R sub in 3.5cuft tuned @21hz

All my amps are very good condition used gear found on classifieds too, you can dig some real treasors for very little money sometimes !

I've been looking all around the web since last week for how to route every sounds of the HU to a USB DAC, translating and reading about 500 pages worth of XDA/Russian Android forums, spent last nights editing config files all around my HU System folder, I tried the how-to link I posted in OP for MTCB units, nothing to do.. I really think the Kernel must be enabled for USB Audio for it to work, my DAC shows up in USB devices info but not in the audio output devices.

Well, I'm still happy because my FLAC music collection plays incredibly well i dont car that much for FM Radio SQ, I only wish I'd be able to listen to Spotify or Kodi on the DAC.

Im r eally glad if I could be any help to you and will keep this thread updated if I find something !

Any update on this thread ?
I made some sort of experiance, on Joying HU , the 2GB Rockchip Sofia version (10.1" screen) :
Using info from https: // source.android.com/devices/audio/usb.html - i looked into the "audio_policy.conf" file on the Joying, and for sure , there was no reference to any USB audio interface.
I am no android expert .. but i edited this file , with the info gathered from the link above , and after a reboot - the HU did indeed send the audio to the USB port.
Audio from all the apps i tred , was routed to the USB interface (Radio , DAB player,Kodi etc..)
The bad thing (?) - there was no volume control , all audio is at max level.
An external volume control could possibly remedy this.. i will look into it

Frank