Please explain the runtime correction (lzk)

reg66

Blackbandt
I can't enlighten you on any of your queries, and I'm kinda guessing you already know this, but in case you don't...
Although we hear and appreciate bass, people/anatomy lack ability to locate and tune in to bass source. We can hear/focus/hone in on most frequencies and waves as the compliment or cancel which gives us depth, stage width blah blah but not so much with bass.

That's why subs in the house, car etc don't need to be (mostly, unless the person is a complete symmetrical audiophile that requires a pair of subs) placed between the speakers and can simply be positioned wherever suits/compliments the overall sound best and/or keeping the sub tucked away or being unobtrusive. In most cases only one sub is required.
So you're right, the bass quantity/volume shouldn't be changing as you adjust the stage focus etc.

Like I say tho, you probs knew that already. Good luck with it all tho

(Can you tell, I've not got much on today! Ha)

Mikescotland

Blackbandt OK, did some tests and may have the answer. May I ask how is dudu connected to your system? Are you using:

Spdif
Left and right analogue out
Do you use a subwoofer.

Blackbandt

Mikescotland Of course you can ask questions.

Currently, I'm still using the speakers directly on the Dudu, without an amplifier. And no, I'm not setting the right and left channels. Dudu has a feature where you can adjust the stage in centimeters, or adjust the speaker delay time. Unfortunately, I don't have a picture right now. It's where you adjust the driver's and passenger seats. Then click on the second menu item at the top and you'll get to what I mean. For me, this is a time-lag correction. As I said, you can adjust the centimeters of the individual speakers.

And no, I don't own a subwoofer

I found a picture

That's what I mean

Mikescotland

Blackbandt I know exactly what settings you're talking about.
Is your system equipped with a subwoofer, like under seat etc?

Blackbandt

Mikescotland No, I only have the front system Eton UG 3.2 VW t5 and as already written my doors are insulated with Alubutyl

Mikescotland

@Blackbandt OK. You say you would like to center the scene. That's not the menu to do so. Volume adjustment between the speakers is in your case "skupienie dźwięku".
The menu you operate is a delay between the speakers (not sure how centimeters are accurate in Dudu, better to use measuring tape and use a delay calculator to get this in milliseconds).
When you change the delay between the speakers, the sound waves coming to your ears might be outside their normal phase and simply cancel each other (can't avoid it). While thus doesn't really matter for high frequencies, low freqs will have this effect with even a few milliseconds out of the phase.
Why is it used then? To measure and apply so all speakers come to your ears in proper aligned phase.

Blackbandt

Mikescotland OK, I understand what you're saying. I've been doing car audio for a while now. And for every Pioneer, Kenwood and Alpine I specified the running time in cm in a menu like that and it always worked with fine adjustment. But the bass was never less intense when inputting in centimeters. Yes, the soundstage shifted, that's true. But the bass was always the same intensity. Not with the Dudu. It's hard to describe. But sometimes the bass is strong, and sometimes it's as if it's coming from below. Or as if you're holding some kind of bass reflex tube. Just as an example.

If the function that Dudu offers is not intended for that purpose, then it shouldn't be offered at all.

And if I use the other menu as you suggested, the passenger becomes much quieter. Like a kind of balance. But that has nothing to do with an LZK. Although it says driver and passenger.

Mikescotland

Blackbandt having said about the theory, lets dive in to the test. Provided you turned off DTS in another menu, turned off reverb and all other crap and left only delay to be adjusted.

What I did it first is to delay on my external dsp left channel speakers by 3 ms.
Back to zero and delayed left channel on DUDU. Also by 3ms. Results are consistent in sound.
I can't replicate your problem I'm afraid. Of course, sound will be different because of the phase.

Blackbandt

Mikescotland I've disabled everything from DTS to reverb, etc. I actually don't understand the problem myself. But as you just wrote, you changed it to ms and not centimeters. Maybe that's my problem. But then what's the cm specification for? And how do I convert it to MS?

Another idea I will try is the following.

I'll take the farthest speaker, in my case the passenger. Set it to 140cm. And subtract 106, which in my case is the driver's speaker. And enter the value of 34 cm for the driver's seat. Maybe that will lead to success.

Mikescotland

Blackbandt
Your right (passenger) should be zero as the farthest one, correct.
Your left driver one is 140 cm away, so according to this calculator should be 3.06 ms.
https://www.erinsaudiocorner.com/timedelaycalc/
(two way system, tweeter and mid same, subwoofer any value as doesn't play here in your case).
1 inch = 2.54 cm

Blackbandt

Mikescotland The right speaker, the passenger speaker, is 140cm away.However, I'm measuring from the tweeter that sits at the top of the dashboard in my VW T5. The driver speaker on the left is 1.06 cm away.

I don't have a 2-way system, but a 3-way system. I have the Ht and Mt speakers on top of the dashboard, and an 8-inch Tmt in the door.

Maybe @DUDU-HUANG @dudu-langzi @DUDU-Meng @dudu-lai can write something about it

Mikescotland

Blackbandt that changes everything, that's I was asking about.
If you have a three way system there is no point and does more harm to adjust any delay on the unit. Delays are set per speaker not per side. From your posts I assumed you have one speaker in each side.
If you have three way speakers and they are in different positions, set everything to zero in Dudu. You try to change delay of the whole speaker group and it doesn't work this way, the phase from each speaker will be mismatched.
I've got 4 way system and each, repeat, each of the 9 speakers has delay separately set as they differ in the distance to the ear.

You're setting delay to the nearest tweeter, but the bass is slightly further away. With low frequencies even millisecond can alter the phase so left and right bass is canceling (or partially cancelling).
You may try calculating delay only for woofers and listen if this sorts anything.

Blackbandt

Mikescotland Thanks for the explanation. Since this is my first 3-way system, you might be right. In my case I use the Eton UG 3.2 VW T5 passive system.Because it was developed specifically for a VW T5. But something tells me that the LZK in the Dudu still doesn't work the way I'm used to. Maybe I'll go to the trouble of hooking up a 2-way system and see if the bass suddenly gets less there too.

But of course I thank you for your help and all the explanations.

Mikescotland

Blackbandt I've tested the delay on DUDU and can't find any problems compared to a dsp (I tested on only one speaker active per side).
I'm not so sure about this speaker system at all, it's a passive system with crossovers and all 3 speakers per side use the same amp. I get it, it's expensive, but to be honest I don't see any way to adjust any delays for such system, especially that speakers are scattered all over the place.
The only compromise would be set the delay using woofers as reference. In that case bass response wouldn't cancel between left and right woofer. However, you will still hear phase cancellations with midranges - depending on frequency, vocals would sound out of place and possibly travel between left and right.
I'd rather leave delays at zero for both sides.
Also remember that passive crossovers introduce own phase shifts, and I can't find any documents for this set with values except there are 6dB/Oct crossovers. With active system it's very predictable because all crossovers are known values and known phase shifts.
The only test response I found for this set is below and I can figure out what frequencies crossovers were used between woofer and mid/tweeter combo. System is designed so the speakers insanely overlap and midrange is actually from all three speakers, the phase shift could be insane between the speakers.
In my opinion, leave delays at zero.

Blackbandt

Mikescotland Yes, I also chatted a bit with a few car hi-fi people. And yes, you're absolutely right that the bass can cancel itself out. I've never noticed this in any of the other systems I've used. But hey, you never stop learning.

Thank you very much for your effort and help to find a solution

Blackbandt

Thanks again to @Mikescotland For the help and advice. I'd like to give a quick update.

It was actually my mistake. In Dudu7, you don't enter each speaker individually, as I was used to. Instead, you take the furthest speaker and then subtract the other speakers from the distance.

In my example as follows

Passenger speaker 140 cm minus driver speaker 106 cm. The resulting 34 cm is then added to the driver speaker.

Now it sounds like I know it and want it

Mikescotland

Blackbandt that's why I always use a calculator and operate dsps always with milliseconds, looks like distance in cm varies between vendors on how they calculate the actual delay.