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-   -   Frankmehta's Polo GT TSI ICE: Android with a twist (https://www.team-bhp.com/forum/car-entertainment/170218-frankmehtas-polo-gt-tsi-ice-android-twist.html)

Just to give you a background, I have been very active in the ICE section over the last few years. People have known me for the monster installs I have done in my previous cars, and as maturity (hahah!) crept in and the cars started becoming more and more complex (for audio installation) I started backing out.

But here's an idea of what I have tried (and even failed, at times) to get the BEST out of IN-CAR-ENTERTAINMENT systems:

MADNESS in the name of Car Audio in my Ford Fiesta 1.6S (when lunacy was at it's peak):

Ford Fiesta S: Eclipse, XBL2 and NOW WITH HORNS!

ICE frankmehta's Fiesta: All Equipment Finalized

FULL Blown Windows Car PC Project in the same Ford Fiesta 1.6S:

An Audiophile Computer in the making: frankmehta's Fiesta S

Digital Audio Processing in a Carputer/Car PC for Dummies

Nice Sounding, High end Honda Civic System:

frankmehta's ICEvic: Guess who's backŪ

The Install that started it all, my good old Esteem Lxi:

Frankmehta’s eS(Q)teemŪ: Eclipse| Illusion Audio| DLS| Genesis| Monster|Hermit

Esteem Mid Life *ICE* Makeover

Frankmehta reviews his ICE: Part 1: Rockford Fosgate 325.2 MONO+Illusion Luccent Sub

frankmehta needs a new head unit!

frankmehta needs a 'NEWER' headunit!

THE PROBLEM



So, turns out that this Android Head Unit saga has taken a very very interesting term today.
http://www.team-bhp.com/forum/produc...y-vw-polo.html

Just to give you a recap, this unit is currently installed in my Polo GT TSI along with some other audio equipment (more on this, later.)

Ever since I have rooted the unit, there was one Golden question. What NEXT?!

The audiophile inside of me has woken up again, after all the other mods to the GT TSi, and I am awake at 4 am on a Saturday night, thinking and overthinking of how I can make the most of this Android Head unit!


The unit doesn't sound good. PERIOD. The audiophile inside of me cringes, every time I go to the amplifier settings of the head unit where I see one page of silly equaliser settings



And one obnoxious page of Fader settings



Now, I am running decently sophisticated equipment in the car.

The front stage comprises of Hertz Energy Components (ESK series)
Rear speakers are Focal Access 165 CA1 coaxial
Both of these are powered by a (decent) Hertz 4 channel amplifier

The sub stage comprises of a Morel Ultimo SC 12 inch subwoofer (my super star) in a sealed 1 cu ft enclosure, powered by a (believe it or not) 1551 W RMS subwoofer amplifier, the Clarion DPX11551 Class G behemoth.

This is not serious equipment, but it requires more control than those 2 silly Android settings..


Now, the Android Unit comes with a low level speaker output that is split into channels of 3 RCA outputs, FR, R and Sub out.
This means, that the head unit is outputting a signal that is being broken into 3 parts by the low level to a high level converter after the signal is output from the head unit. Now this is the ABSOLUTE wrong way of doing things.

Reasons:
1. The head unit has no control over which frequencies to send to what speakers.
2. There is no subwoofer control.
3. The individual speakers outputs are just a formality and need proper high voltage signal to be relayed to the amps, after which the AMP can do a good job of amplifying the signal.
4. The onboard DAC of the Android Head unit is a good one, but the MCU part of the head unit DOES not allow the signal to pass through the DAC due to technical reasons.
5. There are a lot of other electronics and circuits on this PCB, along with the power supply in the head unit, hence the signal is flawed, and a low voltage, noisy signal is being further broken up into front, rear and sub out, without proper distribution.
6. NO CROSSOVER settings.
7. No time alignment.


All this may sound Greek to you, but someone with a brief idea of these terms may totally agree to each point.


PHOTOS: Courtesy, Graaja

THE SOLUTION:

So what AM I doing at 4 am, scratching my head!?!?!


I decided that I need to take matters in my own hands. And so I have come with a very delightful and practical solution.

Now, my Android Unit is a Rockchip 3188 SOC (system-on-a-chip) solution. This means that it has the following components:
1. CPU
2. GPU with sound chip
3. RAM
4. On board Memory SD card
5. USB and other peripherals


One great characteristic of this 3188 solution is the USB OTG function. It means you can attach USB devices like keyboards, internet dongles, mice etc. It ALSO has Digital Sound output over USB OTG.

Which is where my brain started working overtime.

IF I can output a digital, clean and unequalised signal from the Head unit (which means I bypass the crappy DAC and MCU nonsense,) to a USB OTG device via USB, and then, pass this GODLY, pure signal through a High end sound processor, I have my high-end equipment getting a good quality signal, hence making the system sound good.

In a nutshell,



OUTPUT FROM ANDROID DEVICE

(over USB OTG)

EXTERNAL DAC

(over optical cable -- TOSLINK)

EXTERNAL SIGNAL PROCESSOR

(over regular RCA Cables)

AMPLIFIERS

(over regular speaker cables)

SPEAKERS


I am going to explain this better tomorrow..

Till then, questions are welcome.

(to be continued in the next post.... EQUIPMENT)

The Equipment:

After days of poring over forums, I realized that poring over forums for audio equipment is as pointless as looking for a needle in a haystack. It's just POINTLESS to look for audio equipment online, based on reviews, as what one person may perceive as awesome may be mediocre for the other. So, looking for equipment online is a huge risk. I've learnt it the hard way. I have spent HUGE bucks on equipment before and have felt it not being worth the hype. The words, 'forum boner,' come to mind.


Anyway, so I figured, it just doesn't make sense to spend so many hours reading online reviews and decided to pull the plug on 2 products that I happened to come across while just casually browsing the web.

1. THE DAC (digital to analogue converter): miniDSP miniSTREAMER:
miniSTREAMER is a miniature, native 24/96kHz USB audio to SPDIF/I2S interface.



The job of the miniSTREAMER is pretty simple. The USB Host of the Android unit will output true 24/96 khz digital audio to it, via USB OTG cable. The miniSTREAMER just has to be honest enough to relay the true, unprocessed signal from the head unit to the processor digitally via a coaxial cable without colouring it or splaying it with any noise etc.
So, in this case the 'DAC' is NOT converting the signal to Analogue.


More Information:
https://www.minidsp.com/products/usb...e/ministreamer

2. THE PROCESSOR (digital signal processor): miniDSP C-DSP 6x8
6 x IN, 8 x OUT digital audio processor for Mobile/Car audio installations.

The miniDSP C-DSP 6x8 is a Digital Signal Processor (DSP) targeting mobile/car audio installations. Leveraging years of experience building reliable platforms, miniDSP engineered the C-DSP 6x8 to pack plenty of processing power and I/O into a small and sturdy enclosure—a perfect fit for installations with limited space.

On the hardware side, the audio configuration of 6 x inputs (analog and digital) by 8 x outputs is perfect for multi-way setups. Don’t be fooled by its size or its price, this small enclosure packs high quality converters and enough DSP power to make your audio tweaking dreams come true. On the software side, the software application allows real time control of the unit via its driverless USB interface. The onboard microSD card slot supports offline configuration and firmware updates if you ever miss your laptop. Finally, the C-DSP 6x8 will follow in the footsteps of our product line with constant upgrades via new plug-ins and new features. Stay tuned for an exciting new ride!

Features
172MHz 28/56 bit Processor
Digital and Analog inputs (Low/High levels), 8 analog outputs
Windows/Mac compatible GUI
Remote unit up for preset/master volume control







The role of the C DSP is much more complex than that of the miniSTREAMER. Once, the signal reaches the DSP, it has to route the different frequencies to the different outputs that can be assigned to the C DSP by the user.
The C DSP connects to a regular Windows/MAC computer via USB connection and allows you to tweak EVERY possible aspect of the final signal that goes to the amplifiers.

Screenshots below:








The C-DSP software is quite intuitive, has a small footprint (in terms of system resources) and allows you to tweak crossover points, time alignment, equalizer settings, volume level, amplifier gain, phase inversion etc. Finally, I get my control over the sub-woofer back! It was a pain to have the sub either
The C-DSP software works on the Adobe AIR API and is a breeze to use.

The best part about the C DSP processor is the fact that it comes from the factory with a remote control that has 4 presets, and one main Volume button. The presets allow you to outline various scenarios and multiple audio settings, and helps you switch to different presets on the fly, for say, different types of music etc.




The said equipment has shipped and I will be installing it in my car soon.
In the mean time, the thread will be open to discussion.

Kudos for your effort.

I did the same on a 3066 quad core processor android board along with a native IPS HD panel (makes a lot of difference for smaller texts) in my Duster but I was not interested in processing it. Used Beresford Caiman DAC and ODAC (currently using) to a 2 way passive setup. However android cannot do bit perfect digitial out and will down scale the 24\96 to 44.1\48KHz internally (depending on the kernel), eventough its downscaling I felt a lot of difference in the 44.1KHz and 24/96KHz original FLACs, may be because of better sampling rate and the way its recorded. Its customised to work like a media server and supports upto 5TB (tried upto 3TB).

BTW, how much was the landing cost of the minidsp, any idea how much will be for the assembled bare boards? Also waiting for any android app from them to use the DSP on the fly, seems they have no immediate plan for android (they had a plan some time back, donno about the current status). For conversion you can use any decent quality USB to SPDIF converter.

Thanks for sharing, this is exactly the solution I am looking for and researching for some time now.

I have decided to retain OEM HU in my Rapid to which I usually connect my iPod via USB port.

My setup has Rainbow DL components in front and no rear speakers. DD Class AB amp and ID 12inch sub-woofer.

I want to get most out of my system and have few queries:

Can I just get miniDSP 2*4?

Which plugin did you buy to use with your miniDsp?

I am not looking to change OEM HU so will getting miniDSP?

Is configuring DSP settings easy as have never done it ever?

So from OEM HU where will miniDSP connect, the output of HU will go as input in DSP and then output of DSP in amp?



Thanks!

I dont think the topic of discussion is the addition of a DSP, getting the digital out and using it. I dont think a DSP on a stock unit can change anything unless the unit supports digital out (bit perfect preferred). Moreover there is no point in all these if you are going to listen to lossy MP3 files.

Interesting! should have good results with good set of drivers and amplifier. :thumbs up

Yes, absolutely. The Head unit has RCA outputs which will go into the inputs of the C DSP.


Not bought any plugins, but the UAPP (USB Audio Player PRO) has it's own wizardry and driver that allows USB out, through OTG. You won't need that, though.

https://play.google.com/store/apps/d...layerpro&hl=en



Yes, since you have control over the SUB and a DSP will route the audio better and give much more control over the quality. It may even clean out the signal off it's amplification but I am yet to confirm that.

Super easy. See screenshots.

Output of HU to miniDSP, and DSP to amp. Correct.


Landed cost is Rs. 23k with the DAC, shipping from Hong Kong and all import duties. clap:

For conversion, I don't need a USB To SPDIF. My DAC is USB to COAXIAL.
And the miniDSP supports COAXIAL inputs. So digital to digital. No analogue conversion in between.

DSP on a stock unit will make major quality in difference. Since the OEM unit supports only low level outputs to speakers. Adding a crappy low level to high level converter will only increase noise floor and scope for lossy signal. Also, the DSP can clean up the signal, and slightly increase voltage, hence you have much better sound with a DSP in between. Don't forget time alignment, better crossover separation and control over the subwoofer. WIN-WIN!

Have kept the drivers a surprise.
That's coming up soon!

In minidsp terms the plugin is the windows application that interfaces with the DSP.



As far as I understand a DSP cannot enhance the signal which is already converted to analog, it does by digital filtering which based on an algorithm basically filtering the sinewave with higher amplitude, but I never liked the output. Thats another reason I said if the content is going to be MP3, its of no use as its already lossy and not much amplitude differences.

My comment on the signal was relative to a proper digital signal from the HU and a normal stock HU, yes you can do an active separated signal, but who will go for active setup in a stock HU, reason being the poor quality of the signal.



Didnt get you. Not to offend you, what you have is a USB to SPDIF converter (ministreamer), thats why I told you can use any decent converter, in case if anyone is already having one. Its only a container converter doesnt do anything out of digital domain.

DAC is in the C-DSP, I think minidsp is using the cirrus logic CS42528 dac chip.

How is the experience so far?

Has the C-dsp improved sound as per your liking or you feel a standalone good quality HU would make more difference to sound?

Waiting for my set of midbasses to arrive, after which I will commence instalation.
This is going to be an epic install. The remaining equipment will be revealed as the items arrive.

Look forward to it. Let us know the sound reproduction for various music genres.

Adding trance & techno would be great!

Here, guys! The final system flowchart! Installation will be done in the next few days. VERY VERY excited!