Ok so Ive been looking in to building a Android tablet in to my car to use as a head unit.
Ive been looking around at different tablets and the A7 definitely looks the best for my budget.
Basically im running amps in my car so i need an audio signal from the unit.
I DONT want to simply run the 3.5mm headphone jack cable to the amps cause it will sound shocking.
I was just wondering if there are other ways of doing it.
I was looking in to something like sending the audio out the usb but i dont think they can do that.
But what interested me was using the HDMI audio out and using a DAC (digital audio converter i think) and converting the signal to analogue.
Does anyone know if this is possible at all or if there are better ways of doing it?
Ive been spending hours trying to find out a way of doing this!
There are converters available to go from HDMI to standard RCA outputs.
You could run the 3.5mm output through a preamp - the sound quality is pretty good, especially with good filtering, although a preamp with HDMI or SPDIF input would be better (you'll also need a HDMI-SPDIF adapter for the latter)...
(sorry I can't post any links, but you can google the words in bold)
Are there any Android head units that support optical audio out?
I've been researching the last few nights (hours!) for a WIRED way to get a toslink optical cable to a Audison Prima AP8.9 Amp/DSP.
Are there any electrical engineers out there who have thought about bypassing the onboard DAC to get digital output?
Or.... is my only option to provide <96kHz optical audio to get an AptX lossless Bluetooth receiver like the Neet AptX lossless bluetooth receiver. Can anyone share experience on how well the Android units perform constantly connected to a BT receiver for all car audio? Esp. if you have the new Pumpkins with the Parrot BT card, in case that improves things.
Thanks!
I'm looking for the same answer, i've installed the neet receiver, but unfortunate for me, the head unit does not connect. I don't think it can be used as transmitter.
I've found this, but I don't know if it works...
http://www.matrix-digi.com/en/products/158/index.html
You all may be overthinking this. Turns out plenty of modern android devices can use standard USB audio hardware. You just need an OTG cable, and the kind of USB audio output device that doesn't need a specialized driver under Windows or Linux. I've hooked up many different USB audio dongles you my Galaxy S3 and S4. The S4 wouldn't charge while hooked through the particular OTG cable, but the S3 does. As a matter of fact, I've been using it as the media player in my car for years.
Admittedly, I've only used the optical out on some of my devices occasionally, but I imagine it would still work for most.
Update: Not all supposed "OTG" cables work. This is the one I bought in Jan 2014 that works for both audio and charging on my S3 with CyanogenMod 11: https://www.amazon.com/gp/product/B009YPYORM/
Today I received an Android 6.0 Head Unit from A-Sure for an Audi A3. I connected a Terratec Aureon Dual USB DAC. I got sound, but couldn't control the volume. Changing the android system volume had no effect.
I am considering spending a couple of bucks on the app "USB Audio Player PRO" and test it again. If this doesn't work, i will have to return the unit.
Greetings from Germany
So i had to return the Head Unit. I tried a different one by "Skandinav", with this one there was no sound at all from the USB DAC
retlaps said:
Today I received an Android 6.0 Head Unit from A-Sure for an Audi A3. I connected a Terratec Aureon Dual USB DAC. I got sound, but couldn't control the volume. Changing the android system volume had no effect.
I am considering spending a couple of bucks on the app "USB Audio Player PRO" and test it again. If this doesn't work, i will have to return the unit.
Greetings from Germany
Click to expand...
Click to collapse
Hi,
You need to connect to DAC with digital volume control like Helix DSP Pro
Greetings from Singapore
daviestar said:
(sorry I can't post any links, but you can google the words in bold)
Are there any Android head units that support optical audio out?
I've been researching the last few nights (hours!) for a WIRED way to get a toslink optical cable to a Audison Prima AP8.9 Amp/DSP.
Are there any electrical engineers out there who have thought about bypassing the onboard DAC to get digital output?
Or.... is my only option to provide <96kHz optical audio to get an AptX lossless Bluetooth receiver like the Neet AptX lossless bluetooth receiver. Can anyone share experience on how well the Android units perform constantly connected to a BT receiver for all car audio? Esp. if you have the new Pumpkins with the Parrot BT card, in case that improves things.
Thanks!
Click to expand...
Click to collapse
yes, you can connect to the DAC, thereby outputting digital audio from applications and transport flash drive.
this can be done not only with android devices, but also with conventional tape recorder, some installations you can look at my YouTube channel
unfortunately links for new users are forbidden, you can search by my nickname - "jonjonni toslink Евгений Фещенко"
daviestar said:
(sorry I can't post any links, but you can google the words in bold)
Are there any Android head units that support optical audio out?
I've been researching the last few nights (hours!) for a WIRED way to get a toslink optical cable to a Audison Prima AP8.9 Amp/DSP.
Are there any electrical engineers out there who have thought about bypassing the onboard DAC to get digital output?
Or.... is my only option to provide <96kHz optical audio to get an AptX lossless Bluetooth receiver like the Neet AptX lossless bluetooth receiver. Can anyone share experience on how well the Android units perform constantly connected to a BT receiver for all car audio? Esp. if you have the new Pumpkins with the Parrot BT card, in case that improves things.
Thanks!
Click to expand...
Click to collapse
Well, don't fall into this hole. (warning to new users)
I have the Prima dac/amp, and the sound is amazing, and it can be connected to an Android phone via OTG to Toslink adapter, or via Bluetooth adapter with Toslink out, but it has one very nasty issue: when the amp is starting, and there is no Toslink signal, it won't register the connection. So if you later connect your phone, you have to cycle through the input sources Digital->Aux->Master->Digital to again register your connection.
So unless you connect your phone or turn on your BT receiver _before_ you start the car up, you will need to fiddle with cycling the source (while also driving the car). (That is if you also have the optional control unit with a display.)
Why they designed the device this way is just beyond me.
I hope its all right to join an old discussion.
I have a similar problem, I want to connect an android head unit in my car to an external digital amplifier. The amplifier itself have SPDIF input (mosconi GALDEN Pico 12 channels https://mosconi-system.it/product/gladen-pico-812-dsp/) but I can't find an android head unit running Android 10 with SPDIF output for my car. I've found converting card USB->SPIDF (for example: https://www.amazon.com/Douk-Audio-C...1&keywords=usb+to+spdif&qid=1617899902&sr=8-3) but I still missing some points:
-In Android 10, how do I switch all audio outputs to the converting card? Is it a part of the Android or external application?
-What happen when playing multi channel media (such as 5.1)? does each channel transfer on each on?
-Is it possible to use the same method to BT? The Pico have an optional BT card.
Thanks in advance, Haim
haim_gds said:
-In Android 10, how do I switch all audio outputs to the converting card? Is it a part of the Android or external application?
Click to expand...
Click to collapse
Android usually automatically switches to USB audio when found, but many implementations do not. Sometimes there's a setting in the developer menu for prioritizing USB audio, but sometimes that doesn't do anything.
USB audio of any kind is not supported on my Sony X800D Android TV.
haim_gds said:
-What happen when playing multi channel media (such as 5.1)? does each channel transfer on each on?
Click to expand...
Click to collapse
Multichannel USB sometimes works, and sometimes doesn't. Certainly it can work, such as on many Android TV implementations like NVIDIA shield.
haim_gds said:
-Is it possible to use the same method to BT? The Pico have an optional BT card.
Click to expand...
Click to collapse
Multichannel Bluetooth is not a standard, although some implementations like enhanced aptX can support it.
Have you also considered that SPDIF surround is always encoded, and thus is output at a fixed volume? Your head unit would not be able to control the volume; it would have to be done after decoding, like at the power amplifier stage.
MarkerB said:
Android usually automatically switches to USB audio when found, but many implementations do not. Sometimes there's a setting in the developer menu for prioritizing USB audio, but sometimes that doesn't do anything.
USB audio of any kind is not supported on my Sony X800D Android TV.
Multichannel USB sometimes works, and sometimes doesn't. Certainly it can work, such as on many Android TV implementations like NVIDIA shield.
Multichannel Bluetooth is not a standard, although some implementations like enhanced aptX can support it.
Have you also considered that SPDIF surround is always encoded, and thus is output at a fixed volume? Your head unit would not be able to control the volume; it would have to be done after decoding, like at the power amplifier stage.
Click to expand...
Click to collapse
Do you know of if it's possible to allow the headunits to play higher than 48khz resolution through the optical or coax outputs ?
dfal47 said:
Do you know of if it's possible to allow the headunits to play higher than 48khz resolution through the optical or coax outputs ?
Click to expand...
Click to collapse
Have to ask - what
marchnz said:
Have to ask - what
Click to expand...
Click to collapse
The unit forces 24b 48khz audio, coaxial can output 192khz tracks and optical upto 96khz . Higher resolution audio output.
Neutron or UAPP will allow higher resolution, but you'll probably lose Navi directions as those programs bypass the android audio layer and mixer.
Basically you need a high resolution non- Android media player, with a navi input and mixer, that also has an spdif output.
The Alpine UTX-A09 looks like it can do that, assuming it isn't Android based /doesn't force 16/48 output from all sources when the mixer is enabled (in non "Alpine Direct" mode). Looks like the Alpine pxe-x09 has a mixer, so it should also be able to mix in navigation instructions.
Some of the Helix DSPs may mix or prioritize different inputs - the documentation isn't clear.
If you use spdif connection vs optical you run the risk of creating a ground loop unless the source is floating ie running on its battery power.
You can blow out all your high frequency drivers in a second if the ground loop creates feedback oscillations.
A common ground point may or may not prevent it. Using toslink to couple eliminates this potential issue.
For car hookups best practice to use heavy gauge wire for positive* feed, preferably coming directly from the battery for high wattage amps, source auxiliary equipment from the same end point. Do not daisy chain.
Same is true with home hifi, avoid using spdif cables to couple amps, preamps, receivers, cable boxes, etc. Amps, recievers are designed to be floating and not connected to ground. Do mix earth grounded and floating equipment unless connected by toslink only ie a tower PC with a 3 prong plug and a reciever (2 prong plug, floating).
*if you use a chassis grounding point, use only one and do not daisy chain!
dfal47 said:
Do you know of if it's possible to allow the headunits to play higher than 48khz resolution through the optical or coax outputs ?
Click to expand...
Click to collapse
Sorry for the delay.
DTS has had 96kHz/24 bit for many years, and they work through any SPDIF interface... as you wanted. They don't actually change the hardware interface speed, but rather encode the extra data into the sales 48kHz stream.
I've never bothered to encode anything with it, because I'm guessing it actually makes compression worse. You're squeezing much more data through the same early 90s compression algorithm, and DTS is already lossy enough. Factor-in that higher sample rates are not detectable in blind tests, and it just seems like a bad idea.
Hmm... Unless the 96kHz/24 bit extension algorithm is much more efficient at compression, considering it was introduced much later than the base DTS algorithms in 1991, and may have leveraged more recent technologies. In that case, it would definitely be the better choice. Unfortunately, I haven't read anything about this possibility.
Good reading on the 96kHz/24 bit topic:
DTS (company) - Wikipedia
en.m.wikipedia.org
Get the Rundown on the DTS 96/24 Audio Format
DTS 96/24 is part of the DTS family of audio formats but it's rather rare since the advent of Blu-ray Disc.
www.lifewire.com
Bumping an old, but good, thread. I have exactly the same amp (well, the 5.9), and an Android unit with a TOSlink port - but it seems to be turned off as I can’t see any light coming from the TOSlink cable. Any idea how to turn it on?
I have a FiiO as a backup but prefer not to do SPDIF because I need another device for the Audison to take SPDIF input …
MarkerB said:
Sorry for the delay.
DTS has had 96kHz/24 bit for many years, and they work through any SPDIF interface... as you wanted. They don't actually change the hardware interface speed, but rather encode the extra data into the sales 48kHz stream.
I've never bothered to encode anything with it, because I'm guessing it actually makes compression worse. You're squeezing much more data through the same early 90s compression algorithm, and DTS is already lossy enough. Factor-in that higher sample rates are not detectable in blind tests, and it just seems like a bad idea.
Hmm... Unless the 96kHz/24 bit extension algorithm is much more efficient at compression, considering it was introduced much later than the base DTS algorithms in 1991, and may have leveraged more recent technologies. In that case, it would definitely be the better choice. Unfortunately, I haven't read anything about this possibility.
Good reading on the 96kHz/24 bit topic:
DTS (company) - Wikipedia
en.m.wikipedia.org
Get the Rundown on the DTS 96/24 Audio Format
DTS 96/24 is part of the DTS family of audio formats but it's rather rare since the advent of Blu-ray Disc.
www.lifewire.com
Click to expand...
Click to collapse
Toslink can support 24 bit/192 khz.
Optical coupling is preferred as it carries no risk of creating ground loops; optical isolation.
A ground loop can smoke (literally) all your tweeters and maybe the power amp in a second.
blackhawk said:
Toslink can support 24 bit/192 khz.
Optical coupling is preferred as it carries no risk of creating ground loops; optical isolation.
A ground loop can smoke (literally) all your tweeters and maybe the power amp in a second.
Click to expand...
Click to collapse
I think you accidentally replied to the wrong post. My topic was about the quality of the DTS 96kHz/24 bit encode, which is completely independent of which of the two physical SPDIF interfaces is used.
I just plugged in a cheap pair of headphones and wow, the sound is amazing using the hifi dac. I don't know much about it but I have a much better pair of Sony bluetooth headphones, is there any work around to use the hifi with bluetooth?
I don't believe so. I could be wrong but I very much doubt it.
Sent from my LG-LS997 using Tapatalk
This is a post from reddit user /u/codefyre explaining why the DAC can't be used over bluetooth (this was related to the v10, but applies to the v20 as well):
Not possible. Nutshell explanation:
All audio, the audio you hear with your actual ear, is analog. Sound is an analog vibration through the air.
The audio recordings in your phone are digital. MP3, MP4, whatever. Unless you're listening to an old record or cassette recording, you're playback source is digital.
The DAC is a Digital Analog Converter. A high quality DAC converts high quality digital audio into high quality analog audio. A higher quality DAC generates a better reconstruction of the original analog signal. Because wired headphones are analog, they simply transform the analog electrical signal into analog speaker vibrations.
If you think about this for a moment, you should understand why it can't be used with Bluetooth. BT is a digital protocol, so the connection between your phone and your Bluetooth receiver is digital. Bluetooth receivers typically perform an on-chip conversion of the digital signal to an analog output during playback. Some high quality BT speakers have onboard 24 bit and 32 bit DAC's to improve the fidelity of their audio output.
So, if the V10 allowed the DAC to be used with Bluetooth, your signal would be Digital Source - > Analog 32 bit HiFi DAC -> Digital Bluetooth -> Analog Output. Because your audio quality is limited by the lowest fidelity step in the reproduction chain, your final output quality is never going to exceed the fidelity of the conversion in your Bluetooth device. And because the analog -> digital conversion actually lowers audio quality, the highest quality Bluetooth playback can be achieved by keeping the signal digital until it reaches the output device. Running the signal through the HiFi DAC would actually result in lower quality Bluetooth audio.
If you want to match the quality of the HiFi DAC using Bluetooth, you'll need to buy a Bluetooth receiver with a high quality onboard DAC of its own.
Click to expand...
Click to collapse
Couldn't have got a better answer, thank you.