USB Audio (DAC) support, digital outputs

Chrisjohn

Mitz
I have high level, optical and usb-c connected to my dsp and usb is the best for sound quality, followed by optical.
Still experimenting !!!

Mikescotland

dudu0101 Using the dudu7 optical connection with volume control had bad sound quality.
Dare to disagree. Take a look at RAWCat measurements on Youtube. You won't hear difference between 48kHz USB and Optical. Optical has 90% max volume of USB but that's all. THD, frequency response and S/N are comparable. Optical is several dB more noisy than USB but with 120dB S/N on optical it is impossible to hear the difference. If you hear the difference, it means something is ON in the sound settings in Dudu.

dudu0101

Mikescotland

sorry, but you are incorrect. I like RAWCat and he is correct, but you need to understand that there are 3 options for digital output .. USB digital, OPTICAL passthrough digital, OPTICAL modified digital. The first 2 are great. The last option 'OPTICAL modified digital' which lets you listen to phone calls and control volume is very bad.

Mikescotland

Mitz It uses PCM 1690 that have S/N max 113 dB which is noisier than Optical output of Dudu. For me it's a pointless exercise to use experimental USB DAC support- DSP is noisier than either optical or USB of Dudu.

Isk

dudu0101

You're still using conductor remote to control system volume? Even through usb?

Mikescotland

Isk USB Audio from dudu is pass through, it's always at full level, you can't control it with headunit, therefore you need to control the volume on the DSP - i.e. conductor for helix. Otherwise the volume will be always at max.
Contrary to USB, optical and coaxial allow to control volume on Dudu, you can turn off all Dudu sound processing and have only volume control.

dudu0101

Isk
Yes, I use Conductor to control volume .. USB Digital to Douk U2 to Optical cable to Helix DSP V Eight MK2 (so I can avoid USB HEC for Helix). I cannot make phone calls though (unless I use bluetooth handsfree device plugged into RCA input on Helix and then use Conductor to change inputs from Optical to RCA when taking a phone call

).

Isk

Ghbtunez
Im not sure what you mean? Whats your TG?

dudu0101

Mikescotland

Mikescotland optical and coaxial allow to control volume on Dudu"
If you (1) use optical and (2) do not enable optical passthrough, then yes, you can control volume, but the sound quality is very bad .. so this is not really a good option. So I use optical passthrough for good quality but I cannot control volume from DUDU7 only from Conductor.

Mikescotland

dudu0101 Hold on, are you saying in Optical Passthrough you cannot hear the phone calls???

dudu0101

Mikescotland

Mikescotland Hold on, are you saying in Optical Passthrough you cannot hear the phone calls???

With OPTICAL passthough = no phone calls but great sound quality and must use Conductor for volume.
Without OPTICAL passthough = phone calls and volume control on DUDU7 but bad sound quality. Do not use.

Mikescotland

dudu0101 Ok. I was under impression passthrough on the optical was DSP off and just volume control available...

dudu0101

Mikescotland

Mikescotland I was under impression passthrough on the optical was DSP off and just volume control available...

OPTICAL passthough = does not use DUDU7 DSP and no DUDU7 volume control = great sound quality.

Mikescotland

dudu0101 My unit just arrived today and in process of installing it.
But then I don't get why in optical out the volume is still 90% when passtrough.
Problem is I don't have the external volume control on the DSP and bought this product thinking DSP off but volume works in optical passthrough... I guess will be returning then..

doozy

Chrisjohn

dudu0101 What actually makes the quality “bad”? You can still achieve near full range digital signal even if it’s being resampled, it’s just being passed through the DSP chip. In fact, it sounded identical in quality to the high level outputs feeding my helix.

dudu0101

Mikescotland

Mikescotland But then I don't get why in optical out the volume is still 90% when passthrough

must just be the engineering design/components? I'm not sure why. maybe you can tune around the 90% limitation in your DSP levels? Or copy my setup with USB to DOUK U2 to Optical input on Helix DSP.

Mikescotland external volume control on the DSP

what DSP? what amp?

Mikescotland

dudu0101 Helix but wanted to avoid extra cost of Conductor...
I mean if the passthrough is still via Dudu DSP with all processing off, hence 90% volume (headroom for any EQ etc), I don't get why it doesnt have the volume control.
This is slowly becoming a very costly experience.. 🙂
Amps - Pioneer and JBL Stage, Hertz Mille Pro and Audison speakers.
Problem is - I do want to have phone calls!

dudu0101

Mikescotland

Mikescotland passthrough is still via Dudu DSP with all processing off, hence 90% volume (headroom for any EQ etc), I don't get why it doesnt have the volume control.

for OPTICAL passthrough, it would not make sense to have volume control because then it wouldn't be passthrough. I posted a question on this forum to ask why OPTICAL without passthrough is such bad quality and asked for fix, but the DUDU admin reply was that is was very difficult to fix!? not sure why.

dudu0101

Mikescotland

Mikescotland Problem is - I do want to have phone calls!

Let me know how you go .. maybe you have better success .. here is my current setup for phone calls, so I connect a bluetooth handsfree setup into the 3.5mm jack, then change input to Helix using Conductor. Works ok but even the latest bluetooth 5.4 handsfree devices with great reviews have average call quality (compared to Tesla and modern cars).

Mikescotland

dudu0101 Yes I know. Yet, the optical isn't a true pass through, as the level is not full. Oh well...

Isk

dudu0101
How does it take to switch sources? What helix dsp are you using?

I just bought a used Helix Pro Mk2 and I've read it can be slow to switch sources sometimes. I was hoping to avoid a Conductor but now I'm even more concerned about the sound over USB or Optical.

Are you getting sound from other apps, like Waze or YouTube? Sometimes I listen to .pdfs as well, Ai use an app called Evie or @vociealoudreader. These will work with AA, but I hate the AA overlay.

I did make a buy for the 12bg/512gb 9.5", plus 2 sets of TPMS and 360° camera. But idk some of these issues might be deal breakers for me.

Thanks for all the help btw!

Mikescotland

dudu0101 installed, updated and
Spdif passthrough has phone calls. Volume works. Internal dsp is off. Signal per REW is clean, 120 S/N.

Isk

dudu0101

What are you using for your microphone when using the Douk for your BT phone calls?

dudu0101

Isk

Isk How does it take to switch sources?
about 0.5 seconds .. instant

Isk What helix dsp are you using?
Helix V Eight MK2

Isk I was hoping to avoid a Conductor
you will have to buy, unless you use bad quality Optical without passthrough or high level outputs then reprocess in your DSP.

Isk Are you getting sound from other apps, like Waze or YouTube?
Luckily, yes all good with apps .. just phone calls do not work

doozy

Isk I know you asked someone else, but: I use a dsp3. Source switching via director is instant. It’s the auto switching thats a tad slow.

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