Dumdum
Senior Member
If it’s built into the dash and looks like a factory screen it’s fine
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MekedeTech DUDU7 Android Head Unit Review
- Thread starter amirm
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OP
- Thread Starter
- #83
I have explained it in bits of pieces in reviews. This is an Airstream RV built on Mercedes Sprinter van platform (24 feet). RV company wanted to be nice and put in a now ancient Kenwood head unit running Android. It is slow as pig in mud and aggravating to use. Original Mercedes speakers were left in the doors and dashboard facing up. They put in a subwoofer way, way in the back. I needed the space that the sub took for Lithium battery conversion so that came out. The sub was boomy anyway. I then replaced the 4 inch $1 OEM door speakers with JBL 6.5 inch. That made things a bit better but not much.
The new system calls for a new head unit connected with Toslink to a DSP amp (Audison C8.14). The amp section has 8 channels allowing me to bi-amp the fronts and drive the rears plus 2 channels left for passive sub. The slim active sub is under testing and evaluation. I started with the JBL SL2. It did add some bass before getting horribly distorted in my limited testing. There is not room for anything big. Without a sub, there is just no bass. But the rest with the new amp is sounding surprisingly good!
The new system calls for a new head unit connected with Toslink to a DSP amp (Audison C8.14). The amp section has 8 channels allowing me to bi-amp the fronts and drive the rears plus 2 channels left for passive sub. The slim active sub is under testing and evaluation. I started with the JBL SL2. It did add some bass before getting horribly distorted in my limited testing. There is not room for anything big. Without a sub, there is just no bass. But the rest with the new amp is sounding surprisingly good!
nathan
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LOL looks like that's near Grass Valley.
energizerfellow
Member
Probably best to create a new thread just for this project? Even if no further work is done on your Mercedes, I bet a lot of people would love to talk about a project like audio in a 24' RV.
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Hi, @amirm,
I've had problems with S/PIDF (Toslink) connectors (and especially for in-vehicle applications) because the plastic snap-on fit of the cable-connector ('male') becomes a weak link.
I suspect that such little bumps (red circles/arrows) is all that retains the cable connector in the bulkhead receptacle ('female').
I have replaced all my Toslink cables to metal-housing (not 'metallized' or 24K) versions in the hopes for better contact and less potential for problems in firm engagement.
Cheap car insurance!
norcalscott
Active Member
Hahaha good catch! I don't live far from there.
OP
- Thread Starter
- #88
Very good point. I will be sure to make sure it doesn't fall out. Had not considered this in the context of a car stereo vs home. Even at home I find these connectors to want to fall out sometimes with slightest pull.Hi, @amirm,
I've had problems with S/PIDF (Toslink) connectors (and especially for in-vehicle applications) because the plastic snap-on fit of the cable-connector ('male') becomes a weak link.
View attachment 454745 View attachment 454746
I suspect that such little bumps (red circles/arrows) is all that retains the cable connector in the bulkhead receptacle ('female').
I have replaced all my Toslink cables to metal-housing (not 'metallized' or 24K) versions in the hopes for better contact and less potential for problems in firm engagement.
Cheap car insurance!
jannek
Active Member
Because Mekede advertises that a possible audio output can also be to an external DAC or USB to Toslink/Coax converter and the graphics lead to the assumption that the internal DSP is bypassed then - did you test this possibility? Would really like to know if there is a way to get a clean digital signal out of these devices.
Also there are some DSPs with USB in as well - the audison is unfortunately not. But also a small interface like the Douk Audio U2 or even a Topping D10s could provide the digital connection.
Also there are some DSPs with USB in as well - the audison is unfortunately not. But also a small interface like the Douk Audio U2 or even a Topping D10s could provide the digital connection.
OP
- Thread Starter
- #91
The same claim is made regarding Toslink and we see that the Android stack is in play. Don't see how USB connection does anything for that. That feature is in "beta" so no, I did not test it as I intend to use Toslink.
jannek
Active Member
I'm referring to this graphic:
Toslink is preferable in my experience to avoid ground loops in car . According to users you need apps like UAPP or other to get bit perfect output if any. The SINAD of the Mekede surpasses that of car amps so it shouldn't be a problem even in the quietest car.
jannek
Active Member
I'm into competition car audio (sound quality) pretty deep for a while.
Of course mostly car audio is used when driving and ambient noises are too high to recognize any noise of the audio system in the -80dB region. But in competition the car is standing and no engine running. This use case is relevant to try to get the best signal quality you possibly can.
I agree that toslink is an easy way to avoid ground loops, as well as possible influences when routing (badly shielded) low level signal cables together with power supply cables.
Since there is no Android Head Unit with a newer Android than 13 there is no native bit-perfect USB audio, but because of the graphic I posted above I thought it might be possible that parts of the audio stack might be bypassed when using USB audio out. But maybe this only means that USB is capable of more HiRes formats than toslink (which is not what I need).
Concerning SINAD of car amps: I think there are some amps with far better SINAD than 90dB. The BRAX RX2 (based on Purifi Eigentakt modules) is just one example - even if a pretty extreme one...
Of course mostly car audio is used when driving and ambient noises are too high to recognize any noise of the audio system in the -80dB region. But in competition the car is standing and no engine running. This use case is relevant to try to get the best signal quality you possibly can.
I agree that toslink is an easy way to avoid ground loops, as well as possible influences when routing (badly shielded) low level signal cables together with power supply cables.
Since there is no Android Head Unit with a newer Android than 13 there is no native bit-perfect USB audio, but because of the graphic I posted above I thought it might be possible that parts of the audio stack might be bypassed when using USB audio out. But maybe this only means that USB is capable of more HiRes formats than toslink (which is not what I need).
Concerning SINAD of car amps: I think there are some amps with far better SINAD than 90dB. The BRAX RX2 (based on Purifi Eigentakt modules) is just one example - even if a pretty extreme one...
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This is an extreme case but even then i doubt you will find such a capable DSP unit. In that case i have seen Digital Audio Players used as source. Where did you see valid measurements of that BRAX just out of curiosity?
jannek
Active Member
Best I can offer right now is a test of a car audio magazine: Car&Audio International
By far not the testing in detail like on ASR, but at least an indication.
By far not the testing in detail like on ASR, but at least an indication.
Dumdum
Senior Member
The usb acts differently to the toslink and you can set the sample rate it provides which you can’t with toslink, it is not one and the same 96khz sample rate is doable with the usb out
Dumdum
Senior Member
Dumdum
Senior Member
I have graphs from an apx-555 for the Brax RX2 pro if required… they are all serial numbered and recorded at Audiotec Fischer HQ and filed should it ever go wrong they can tell you what components were fitted from the factory this is one of mine, it’s heavily rebuilt using eigentakt technology under license, it’s not as some think the output boards with a 12v power supply
Mine have the digital input cards with the best ESS dac on its input, it uses the dac for volume with a carrier signal in the coax digital signal line when the new pc tool 6.x software is released with disac2 protocols put in place, currently the Dsp just regulates the output level… disac2 should be superior though, it’s like turning the gain of the amplifier down to alter the volume of its output
It’s a heavily regulated power supply and very clean and has a ton of power, far more than my Brax mids and tweeters will ever need
At some point I may end up working for the company and have every intention of making testing with the apx555 in the exact same way as Amir does for various amplifiers and dsps
Nice since you are at it you can use Roon to report if the chain is bit perfect which is probably not when using DSP so i wouldn't care much. Hopefully you can show us some meaningful measurements of these and other gear. There is also a group in FB called distortion factory that measures car audio if you are interested.
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