Digital out sampling rates

Mikescotland

agaxiola89 no. Spdif or coax always have resampling to 48 kHz on its way. However if you choose "spdif passthrough" it will turn off all internal dsp processing except volume control
.

agaxiola89

Mikescotland Thanks!
Now, I don't know what the point of the digital output on the Mekede DUDU7 is if it can't take advantage of high resolution (24-bit 96/192 kHz) natively. I understand that it's still better to use the digital output instead of analog RCAs, but it's not pleasant to have to buy an external DAC to enjoy its full potential.

I don't think I'm the first to request it, but it's an improvement I'd like to see in future DUDU7 software updates.

Despite everything, I'm happy with the device; however, I would have liked to take advantage of that feature; I think it's a point that could be improved. @DUDU-HUANG

Mikescotland

agaxiola89 point is quite valid. Even with all that resampling.
If you connect to your external DSP via audio out analogue you have
Digital > analog conversion in Dudu
Analog > digital conversion in ext dsp
and possibly interference with audio cable from other electrics in the car.
With spdif, there is a digital signal going to ext dsp immune to interference and you don't do unxessesary and degrading (much more than resampling) D-A conversation and again A-D conversion.

Mikescotland

DUDU-HUANG cannot they? I heard Redpower 850 Crystal doesn't have that issue?
What about Pioneer or Alpine on their variation of android?
Problem is noone cares from Chinese manufacturers. Manufacturer wants a board from FYT or someone else, with added something and creates own skin over it. So in fact we have same iteration of exactly the same platform on countless brands, and manufacturer doesn't even get the source code from FYT. Has to be cheap, so it is.
And we have actually one or two companies who developed the base system, once done, so we'll just bump Android version to higher and call it a day.

abidali

Mikescotland using optical output (pass-through) in its current state, is there considerable difference in sound quality?

Sean

@DUDU-HUANG You really need to reply with a specific and clear reply to this question without denigration of the customers and potential customers who are looking for you to deliver what is simply being claimed. This is the question:

Q: Can the DuduAuto be configured to output digital audio via optical output without unnecessary conversion to 48kHz via a software update? Or, is this not possible because the unit has been designed so that hardware limits this possibility?
A:

DUDU-HUANG

Sean

Our goal is to improve the usability of the product while ensuring the optimization of sound output. If resampling is not performed, it means losing volume control, analog channels (Bluetooth, radio), navigation and mixing functions. How many people are willing to do this? In order to listen to music, we sacrificed the convenience of the device. We have been optimizing and testing the audio link. I think the quality of audio is not as simple as looking at the parameter values, but should be listened to carefully. In the latest version, we also compared it with the USB DAC output, and the gap was further narrowed, almost achieving the purpose of lossless output. You can consult other car owners in the Telegram group. Finally, we would like to reiterate our goal, to meet the sound quality requirements of music lovers while ensuring the usability of the product.

Sean

Mikescotland
Thanks Mike. I sincerely appreciate your response. Not an Electronics Engineer but a Chemical Engineer with a fair bit of hands on audio experience (my own home and car systems). So a hack with a decent ear in reality.

I'm going to look at the settings on Roon to see if anything here can be changed. Thank you for analysis -I am new to Roon with much to learn.

I thought that it was me who was the one finding DuduAuto responses to be poor and condescending. I thought that you being so polite and non inflammatory was an indication that maybe I needed to pull my head in a bit. I find their responses appalling and, to be honest, pure deflection, never addressing the issue or question being asked but rather avoiding any real answer.

I really value your input on these forums. It has been invaluable to me. Thank you.

Sean

DUDU-HUANG

Mate I’m no dumbass when it comes to audio. I don’t rely on specs but my ears. Case in point my Storm Audio ISP which operates at 48kHz is simply head and shoulders above every other processor I’ve used and that includes some very expensive units. Those expensive units processed at much higher sampling rates and supposedly the belief by many is that they will sound better and the Storm Audio ISP will be worse. Couldn’t be further from the truth.

But back to your unit. There are still questions unanswered:

Is it a physical limitation to not be able to digitise Bluetooth audio and navigation commands etc so that they can be output along with digital audio WITHOUT resampling? Or is this a software driven issue? Volume control should not be an issue as processors that accept this sort of input are capable of volume control.
Customers are telling you that resampling is an issue to them. I bought this unit based on the advertising and some customer reports but wouldn’t have purchased if I knew that the signal was being altered. My older Alpine units with Optical output never resampled or messed with the signal before outputting it. This is how it should be...

Simple question.

Sean

DUDU-HUANG

It is advised that you obtain and test the product also. Maybe there’s things to learn.

DUDU-HUANG

Sean

This is due to limitations in the audio hardware chain; digitization is not possible.Analog audio includes Bluetooth, FM radio, and external AUX audio input
We've already explained the reasons for resampling. While prioritizing convenience, we're also continuously optimizing the sound quality to achieve the same level of quality as a USB DAC.
You can achieve the effects you want with a USB DAC device.

Mikescotland

DUDU-HUANG just a quick answer regarding no 1.:

you're a bit skirting around. Bluetooth, aux etc are already being digitised. Spdif isn't an analogue output and yet we have sound from these sources on it. If they weren't digitised, we wouldn't have them at all on any of the digital outputs. So, in a nutshell, this point is a complete nonsense answer. If it's digitised by AKM, as per their datasheet, you can sample these signals with any sampling rate. If it's digitised before AKM, by FYT native hardware and then passed to AKM, well, that's a bad design decision, goes along my thinking "let's take standard one fits all FYT board, add DSP and try to sell it as a premium audio headunit". AKM DSP on DUDU7 was designed to replace that one-fits-all-units processing as it has all necessary inputs to perform these tasks at any sampling rate. Sadly it was implemented as an addon at the exit of the audio path, not as the main audio chip to mix sources.
@Sean as you can see there isn't any answer about competitors being able to do it. Iterations of audio in Dudu product line is just adding different exit dsp (ROHM or AKM, the rest is the SAME, audio path before it is the same in all iterations of the HUs).

Sean

Ok so we finally have an answer! You simply cannot make this device perform like it should.

Optical Output -might sound ok but is being altered by resampling to allow bluetooth and navigation to be mixed in.
USB Output- audio is output perfectly but no system/bluetooth audio because it is not designed to allow this.

This in all is simply due to poor hardware design. It could be close to perfect from an audio stand point but poor design choices limit the unit.

DUDU-HUANG

Sean If there is a better solution than ours on the market, you are welcome to recommend the product to us for learning.

Sean

DUDU-HUANG

You are once again being a smart a#se. Customers have essentially been misled - that is where the issue is. And your responses up until your last one were essentially subterfuge and diversion. Your unit might be the best android device out there but I can tell you that my previous Juba Alpine unit with optical output sounded better. But hey it lacks the functionality of the Dudu.

We aren't comparing apples with apples. Our concerns are about the audio side of this unit. It is very good and could be perfect but for essentially poor design choices. So yes, your unit is great from an overall perspective but does lag behind the best audio out there in my view.

Mikescotland

DUDU-HUANG we have mentioned them (with no reply) to you to take a look. So once again:

teyes Cc4 Pro (no independent reviews yet, but they say it can, who knows)
Redpower 850 Crystal (YT videos show spdif dynamically switching to different sampling rates based on sampling rate of the file being played).

DUDU-HUANG

Sean If we compare it to a digital player, we do have some gaps, and we acknowledge that, as the design philosophies are completely different. But my point was, if there are better Android products of the same kind, please recommend them to us so we can learn from their strengths in our next generation of products. We're also constantly iterating and optimizing sound quality. We haven't given up on audio optimization, and we're constantly working to improve audio output quality.

Mikescotland

Sean im waiting for spdif to usb high end adapter. I need to take some measurements, because with spdif out changes in 3.6E I swear I can hear distortions on tracks that approach -3dbfs in volume (something like they set gains higher for spdif out and it's clipping). I'll post it once done.
On the other hand, you can see here how it is, if you object some things that in your eyes look nonsense (forcing lyrics on every widget, inability to open player in minimal mode by just tapping the cover, asking to make navi bar bigger, or in my case reverse navi bar because some people drive on the left side of the road) - you're usually ghosted by Dudu.

abidali

DUDU-HUANG the point isn't that you can only make it better if there's better options out there. Since you've acknowledged the gaps, why not work on it so that the gaps are no more and the audio is perfect. With the great hardware specs, it should sound wonderful, no artifacts or multiple resampling. Could be an option that can be enabled like USB audio.

A lot of people in industry do not like the Android Units because they know the processing is limited by the Android. For example, AK7738 perform really nice in Kenwood Excelon series and not so great here because of resampling issues (even with better AK7739).

I hope and expect your team to consider this and make this device flawless, it is already a good device, will become better.

Sean

DUDU-HUANG

Thanks @DUDU-HUANG . I appreciate the honesty but this simply reinforces my views this DuduAuto have patently false claims in their advertising. You clearly call this an audiophile player in all the available literature. Now you admit that you lag behind decent digital players. I'm happy that you have been so forthcoming in stating this but it leaves a bad taste with customers who care about this aspect of the unit. It also makes me very wary about any claims that the company makes in the future about new products etc and is reputation harming.

JhonnyD

Ich bin sehr gespannt, wie sich das CC4 Pro im Vergleich zum DUDU7 schlägt.

Mikescotland

JhonnyD we don't know. I was wiling to buy one unit and test but it's not available yet to buy in the UK. Redpower 850 Crystal seems to have it all, but it's available for now only in Russia. ☹️

Sean

Mikescotland

Looks like the Redpower 850 crystal is available on Aliexpress with shipping to Australia. I figure that they'd also ship to the UK.

DUDU-HUANG

abidali I understand what you mean, we will work hard to optimize and improve the audio output

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