Crack at Stop

[PeterSt]

The peak is at about 1,5Volts

Carsten, besides my other question about the consistency of your earlier post, I find it hard to believe that this is 1,5V (DC !?) only. So, connect a nornal 1.5V battery to the input terminals of your speaker and watch (excursion) / listen (small tick) how harmless this is.

Maybe your Volt meter is "slow", but maybe this is another indication that something is reacting (?) strange.

Btw, don't switch on Ph + with Normal Phase. Same for Ph - and Inverted Phase. *That* would explain what you see I guess ...

Yea, uhm, but ...
When your Absolute Phase is inverted somewhere along the lines all works the other way around MAYBE. So when you perform this correctly (see above) you just as well may try doing it the wrong way. So, switch on Ph + while using Normal Phase in XXHighEnd ... TRY THIS CAREFULLY because when I am wrong here (and probably I am), the "crack" will only be worse.

Peter

[praphan]

Hey Praphan, thanks.

Then at the hit of STOP the large LF AC pulse kicks in.

Must I read this like : also without PA this happens ?

Hello Peter,

The answer is "no". The strong LF pulse kicks in only with PA engaged. Without PA, XXHE on my system works perfectly well. No noise , no stall, smooth as silk though but not as pure as PA mode.

Regards,
Praphan

[CaOd]

Sorry for expressing myself in a misunderstandable way, I still have to sort out what is happening here.

I have done some measurements at the DAC, without the Amp running.

The whole problem already lies here, so we should not suspect the amp. The DAC has a headphone outout. When playing with or without PA engaged, I measure a constant DC-level of -1.8mV, so I guess a normal behaviour and not related to XX, nor to XX with PA engaged. During normal music playing with maximum volume, I get AC levels of max 100mV. When I hit stop, I get a peak of DC (!) of 1.5 Volts. A little more accentuated on the left channel, but I guess that depends on the music playing.

The same thing happens on the line outputs. No DC during normal play, when hitting stop, I get a huge DC burst of 1.5Volts. Why this is getting through the amp I have to ask the manufacturer. But it would be better if it would not happen at all. So it must be somewhere in the XXHE-DAC route.

Sorry to bother , I would love to dinf a solutin for this.

Best Carsten

[CaOd]

Sorry Peter, I had not read your suggestions on the device buffer length, will try asap

[CaOd]

ok, things change somewhat with those parameters.
I have put the buffer length in the Weiss panel to 256, which is the minimum. When I change the setting in XXHE also to 256, things get worse. But if I leave the setting in XXHE at 4096, while putting the Weiss control setting to 256, the crack gets a lot softer. All this with Q1=15, xQ1=1. Lower Q1 values make things worse. Changing clock resolution does not make a difference. Higher Q1 values up to 30 do not change it much.
Hope that helps best Carsten

[stefanobilliani]

Hi All ,

I did some work around this PLOP at Stop issue .
Since I did read a lot of things about amplifiers and such ( some of them rather displeasing ) , I want to put a couple of pictures that hopefully will clarify a bit what is happening at the stop (or when we push the stop button in XXHE) of the song with PA working . Notice that the following pictures do show a *good* case when the bad cracks are not happening . What we see , are some loops ( I think many people here know that already ) and the stop itself , that we *perceive* as a bad plop .

Set UP : In this test I didn't use a real DAC at all . Infact I did use the Virtual Cable ( which can be configuarble up to 16X sampling frequency/32 bit operation and for KS) .
Then I just recorded the sound directly from the software via windows . So: no real USB to I2S is involved , no real USB DAC is involved .

Then what we see in the little sample representation is 2 channels of the stereo song playing at around -30db , then we see the samples repeated at the end when Stop is Pushed in XXHE .

Again , I did this to have an idea of what is going on . But I think is close to what happens in our USB DAC setup .

In the first figure we see the meter ( in ROSE color evidence) and the song position triangle ( in ROSE color evidence) during playing music .

In the second figure we see the meter ( in RED color evidence) and the song position triangle ( in RED color evidence )just about at the end of the whole thing.

What I do note , is that *during* the 2 sample repeats , the level of the sample drifts from 0 with respect to its "symmetry" . The METER of the player ( or editor ) shows incresing volume ( (see the RED Evidence ) but of course we do not hear this increase at that moment ) that then stops as a form of plop .

I have the recordings made at 88200 , and of course the plop is there as a reproduction for every player , and yes it is audible just the same .

stefano

PS : volume in XXHE was set at -9 db . PH - and strenght 0
      PE + Arc Predict (2X).

[PeterSt]

Hi Stefano,

I am sitting here with a big smile looking at your analysis. Great. And sure it shows what some perceive. But one thing :

88.200Hz (2X) AntiImage filter

W r o n g ...
And no, not your fault. Mine. Nobody asked or noticed thus far, but I did last week myself ... So, in the version I use, PA is not possible outside of Arc Prediction ...

I honestly can't even predict what happens with AI, but your graphs show a sort of reversed effect.

Small issue : This will not be Carsten's problem.

What I (seem to) learn from this, is that I possibly can build in protections against this "reversed" work out ...

Thank you Stefano,
Peter

[PeterSt]

Carsten, maybe you can get there after all ...

Higher Q1 values up to 30 do not change it much.

Not much ? to me that seems "a little", or anyway : something.
Now, you must realize that Q1=30 is only twice as long as Q1 = 15. This is not all *that* much. It becomes much when you now start dialing Q1Factor. So, set that to 2 and again it is 2 times larger. And so, 40 is 40 times larger than when set to 1.
It would be my idea to slowly increase it and watch what happens.

Regards,
Peter

[PeterSt]

Carsten,

During normal music playing with maximum volume, I get AC levels of max 100mV.

Don't you mean DC here ?

The same thing happens on the line outputs.

Don't you mean "speaker outputs" here ?

Why this is getting through the amp I have to ask the manufacturer.

Maybe not.
(*remember*, this burst of 1.5V at the end shouldn't be there in the first place !)
I don't think this DC can be blocked, because it is not DC. On this matter we may just as well look at Stefano's graphs, because no matter it is a wrong situation incurred for there, it sure is representative for what happens. So, look at the right side of the graph ... that is no DC. So, supposed that "end period" takes 2.8 seconds or so (looking at Stefano's graph), there's a change of voltage from 0 to the 1.5V in 2.8 seconds. Call that a(n AC) frequency of 0.075Hz  (4 times the length of what you see for a full cycle), and I don't think that can be blocked. Mind you, this is this end period.

Yea, uhm, but ...
When your Absolute Phase is inverted somewhere along the lines all works the other way around MAYBE. So when you perform this correctly (see above) you just as well may try doing it the wrong way. So, switch on Ph + while using Normal Phase in XXHighEnd ... TRY THIS CAREFULLY because when I am wrong here (and probably I am), the "crack" will only be worse.

And ?

[stefanobilliani]

Hi Stefano,

I am sitting here with a big smile looking at your analysis. Great. And sure it shows what some perceive. But one thing :

88.200Hz (2X) AntiImage filter

W r o n g ...
And no, not your fault. Mine. Nobody asked or noticed thus far, but I did last week myself ... So, in the version I use, PA is not possible outside of Arc Prediction ...

I honestly can't even predict what happens with AI, but your graphs show a sort of reversed effect.

Small issue : This will not be Carsten's problem.

What I (seem to) learn from this, is that I possibly can build in protections against this "reversed" work out ...

Thank you Stefano,
Peter

no prob Peter

I did noticed this morning , that into Anti Image filtering there wasnt sample repeats and other things for the first time , but ... it was late .. late and more over engine3 would crash in that situation ( ... ) .

Well . Not bad for now

:-)

stefano

[stefanobilliani]

Hi Stefano,



I honestly can't even predict what happens with AI, but your graphs show a sort of reversed effect.

no there isn't a reverse effect , but just a conga playing in the music just when the stopping  sequence commence ( PE/AP) .

So what I did call " first loop " effectlively will be repeated after  one time ( second loop ) and a third time just in part .

S

[CaOd]

Carsten,

During normal music playing with maximum volume, I get AC levels of max 100mV.

Don't you mean DC here ?

No I meant AC, thats the normal voltage to drive a speker coil.

The same thing happens on the line outputs.

Don't you mean "speaker outputs" here ?

No, line output, since I was talking just purely about the DAC and its various outputs (headphone, line out).

Why this is getting through the amp I have to ask the manufacturer.

Maybe not.
(*remember*, this burst of 1.5V at the end shouldn't be there in the first place !)
I don't think this DC can be blocked, because it is not DC. On this matter we may just as well look at Stefano's graphs, because no matter it is a wrong situation incurred for there, it sure is representative for what happens. So, look at the right side of the graph ... that is no DC. So, supposed that "end period" takes 2.8 seconds or so (looking at Stefano's graph), there's a change of voltage from 0 to the 1.5V in 2.8 seconds. Call that a(n AC) frequency of 0.075Hz  (4 times the length of what you see for a full cycle), and I don't think that can be blocked. Mind you, this is this end period.

Yea, uhm, but ...
When your Absolute Phase is inverted somewhere along the lines all works the other way around MAYBE. So when you perform this correctly (see above) you just as well may try doing it the wrong way. So, switch on Ph + while using Normal Phase in XXHighEnd ... TRY THIS CAREFULLY because when I am wrong here (and probably I am), the "crack" will only be worse.

And ?

I can switch Phase at the DAC and at XXHE. Original was DAC=+, XXHE=-. When I keep the DAC at + and switch XXHE to +, the cracking sound varies a little bit, but not much. Just a little crack more before repeating the last buffer. The crack at the end might be a tad softer, but not really noticeable. Keeping XX at + and switching DAC to - gives the same pattern like the beginning (i.e. DAC +, XX -). No big changes here.

I have also increased xQ1 now from 1 in little steps all the way up to 40. What changes (clearly) is the length of the repeated buffer, but the crack at the end (and a littel one before repeating the last buffer) stay almost the same, might again get a little softer all the way down to 40, but not really considerably. Still sounds frightening at higher volume levels. The biggest change was really setting the DAC control panel buffer length to 256 and keeping the XXHE setting at 4096.

Thanks for all the help

Carsten

[PeterSt]

Hey Carsten,

Regarding your Absolute Phase tests, I have the feeling that you did not understand what I wanted you to try. But maybe my text was too much out of context. This is what I meant to say :

In XXHighEnd you can have Normal (Absloute) Phase or Inverted (Absolute) Phase. This is what the IPhase button is for. When not active it is Normal Phase.
Now, when Normal Phase is active, Phase Alignment should be used in its "Minus" form. So, think like something needs to fight back against plus. So, Minus fights Plus;

You can just as well use Inverted Phase because your chain inverts it somewhere (often DACs do). So, now in XXHighEnd Inverted Phase is output, and e.g. your DAC makes it normal again (because that Inverts too). This is what the IPhase button is for and always has been for. However, thinking about Minus wants to (intendedly) fight Plus, now you logically need to use the Ph (+) Plus button.

The above is the normal situation of usage.

Now :
a. you may be using this wrongly;
b. you may NEED to use this "wrongly".

My suggestion in the earlier post(s) was to try b. But of course when not first a. applies.
So, when a. does not apply, it was my suggestion to use Normal Phase with Ph+ OR Inverted Phase with Ph-.

(and what you did was just playing with the Absolute Phase settings on either end of the chain (XXHE vs DAC) without ever telling about the Ph+/- settings which already make me believe that you can have it "wrong" in the first place ...)

Ok, so what I want you to try out is pretty easy to follow now, I assume. And so here I should stop talking ...

But I don't (so watch out not to get confused again) because what further can be in order I can't get myself. So, it is for a reason that you can set Ph+ together with Normal Phase. Thus, as explained above, this would be an "illegal" situation, but sadly *now* I don't know what happens when this illegal situation is fed to a DAC which inverts the Phase. And this is just an example, because preamps and amps can invert the Phase as well. It is just a so crazy difficult thing (and possibly the most difficult I ever made in my life) and I can't reason it out. But what SEEMS to be happening is that the workout in your chain incurs for that "reversed" effect just because something inverts along the lines, *OR* a. above is in order in the first place.

Is it more clear now ? ()
Peter

[CaOd]

ok, I got it, I had read in the IPhase description that it would only work for Engine#3, but I was wrng, I probably need to wear glasses...

I have worked out the following combinations:

Iphase   Ph+   Ph-   DAC_Phase    Result
------------------------------------------------------
  off         off     on          +               crack
  off         on     off          +               softer crack
  on         on     off          +               softer crack
  on         off     on          +               crack
  off         off     on           -               softer crack
  off         on     off           -               crack
  on         on     off           -               crack
  on         off     on           -               softer crack
       
softer crack means that the last buffer gets repeat with alittle lower volume, but very distorted and the crack is still audible, but a little softer, but nothing compared to the changes that I got with setting the DAC panel to 256.

All tests were made at Q1=14, xQ1=2, Buffer length in XXHE=4096, Buffer length setting in DAC panel =256.
Then I have left the DAC setting at 256, set xxHE buffer also to 256 and put Q1=30 and xQ1=16 (system would still play ant unattended!) and that gives again a little relief to the crack, but not letting it go away. But I get an error message about clock resolution (15ms asked, received 1ms). Seems to be controllable.

But what I have noticed is the following, not knowing if this is normal or not: XXHE choses enginge #4 for the DAC, but when I look in the TaskManager, a process (or task) is active called XXEngine3 ??? Normal?

Do you call all this case a) or b) ?

Cheers Carsten

[SeVeReD]

I get a very loud "crack" when the playlist stops or I hit "stop", either in unattended or in attended mode. The crack can e compared to putting a needle on a vinyl disc at full volume,
 

Welp

After having everything go well, I decided to pull out the volt meter and read again about Phase Alignment to check it out.  I have two Bryston mono amps that work the bottom end of my speakers and one Moscode 401HR  stereo amp that works the top end of the speakers.  (I also have 3 Sunfire subwoofers that get their signal from the Bryston amps via speaker cable; they have internal amps...hmm never checked them).  The Bryston don't pass DC and the Moscode swung from 7mv to 20mv while playing with speaker cables off and -30db.  Ok try with speaker cables.  Everything good to go...
until I hit Stop or album ended.
very loud crack. and at normal volumes just way too loud and scary.  I can't afford to damage the system so...
So I'm off the PA until I/we figure this out.  I suppose I could try turning down the vol right before 'stop', if I really want to listen and evaluate...

no cracks, pops ticks at beginning .middle of songs... but man, when I push stop or it comes to the end of an album all hell breaks loose.
I"ll change my sig soon so you can see where I'm at.  I was  even able to use special mode this time and everything ran well.  I'm using  both special or adaptive mode at the moment.  Everything runs great.... just not PA.

oh ya, this crack at stop happens whether I have the Brystons shut down and the Moscode on, or vice versa.