Crack at Stop

[CaOd]

Hi there,

I am still overwhelmed by the sound of your new release, Peter, just amazing what a decent PC-DAC combination can produce in terms of touching musicality!

Esp. the PA and the Play from Drive option makes all the difference!

It all played well on my system and with the settings I am currently running (see my sig) with one exeption and I couldn't really solve it by following other posts here regarding plops, cracks etc (hope to depict the sound I am hearing correctly).

Besides the little ticks after every song (woulnd't even bother me at all), 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, really giving a blue burst in my poweramp valves. If I don't turn the volume down before I even fear to fry my speakers...

As recommended I have tried to go as high as possible with Q1 and xQ1 settings, the system plays music (although receiving the warning message that the combination of... is larger that 122880 and only one track might play in attended mode) at Q1=15 an xQ1=40. But all with the same crack at stop. Same with higher Q1 values, but music only plays with low xQ1.
At Q1=15, I have tried xQ1=1,2,3,4,5, the all give the crack.

Any idea how to proceed?

Other than that I will live happily ever after (...still have to figure out how the Gallery feature works, obviously I always load the pics from my HDD music folders, not from the SSD...)

Thanks again for this milestone in computer audio

cheers Carsten
 

[PeterSt]

Hi there Carsten,

With a big thank you for the nice words, to me it looks like we have a new phenomenon at our hands. Not sure, but it seems so;

In order to me being on the right track, you must observe your Weiss without PA. Now, I am fairly confident you hear ticks all the time (not really always but more than half of the time), especially when you don't play at the set sample rate in the driver (I think this can be set although I never managed; anyway, it *is* set at some rate).
True ?

If this is true indeed, especially at the *start* of a track, you can try to recognize whether this is actually the same. Btw, I wouldn't describe what happens at the start as a crack, but merely as a (way too loud) tick. Remember, just without PA.
*If* you have these ticks at the start at all, I think we should try to find the culprit in the Weiss driver. Not that we must solve it in there (via Weiss etc.), but it would be good to know it's actually the same problem.

If the above is not it/related, there's the other chance of the filtering in the Weiss bugging us. So, (digital !) filtering as such works upon the sequence of samples and roughly put, it will make a nice filtered sequence out of that. But, this anticipates normal music behaviour, and what happens at stop is not that at all. So, only listen to what happens (if you could without "cracks" or whatever it is) and you'd hear a buffer repeating. On that matter, the higher Q1xQ1F the longer the repeat lasts but also the less repeats. Anyway, this is about the end and beginning of the buffer -when connected like what happens- not being music. So, there can be a larger voltage jump, depending on the last sample of the buffer and the beginning of the same buffer (which thus is played after its own end). This voltage jump can be audible within itself, and I know -using the NOS1 which doesn't do a thing for filtering- that this can be audible. But, this is coincidental and when I hear something like a small tick once out of 50 times, it will be much. What I'm saying is : the voltage jump itself is not doing it, or otherwise I would be hearing it just the same. But now the filtering ...

I know from your Weiss that it can produce totally distorted music if only the music is too squary. So, here too the higher voltage jumps occur, but now we call them high transients. This is not what the Weiss can deal with very much and remember, this is about the filtering. So, the algorithm in there can not make sense out of too high trancients, also explicitly referring to filtering generally being *about* eliminating high transients, because that's what's in Redbook unfiltered (like a 20Khz sine implies a square because only two samples can form a 20KHz sine).

Still there ? Then now you can maybe see better how ticks in between tracks emerge if they only are with gaps. Here too those filtering anomalies happen, but now in XXHighEnd. It is just difficult to solve.

My last option for now would be the sort of strange habit of Weiss (but others sure too !) that it's actually advised that playback software should start with 2 seconds or so of silence (ask Daniel). Although this will help the Weiss to avoid the loud tick in the beginning, it is a backdoor solution. I mean, yes, *I* could solve that for Weiss and the others, but actually it is a DAC problem and I don't say it is easy to solve in-DAC. Now watch this :

What I suspect is that at least the Firewire drivers in general (from DICEII which your Weiss will be based upon) are clunky (well, they are and always have been) and that something happens like the playback software tells to start, but the driver right at that time starts streaming. Wrong, because it didn't receive "sample rate switch data" yet. This is where the tick at the start happens. So, the first couple of samples are played at the wrong sample rate and such, and this is where the tick comes from; actually it's a very brief moment of static. Now the stopping ...
When the software plays the last buffer at some point in time it will tell the interface to stop playing. This is when the last buffer is empty. However, this is when the software is TOLD that the last buffer is empty. And this can easily be wrongly programmed. So, playback software hears that last buffer has been played, it stops the device, but in the mean time the driver isn't playing out the last buffer - it just stops right away. It is similar to the start problem, though different. But made by the same programmer who didn't know all about it ...
So, this last buffer needs to be played, or otherwise there's an abrupt cut of the sound, and that means "depending on" again, a large voltage drop (a super transient downwards).
Without Phase Alignment this can be audible already, but with for sure it will.

Enough blahblah. But with this "information" you might be able to see better what could be going on.
Notice that I could provide another parameter which anticipates the early stop like described, but it gets more and more complicated. Not only for me, but for sure for people like you. But if it helps ...
Btw, I'd think that shortening the buffer in the Weiss control panel could help here. So, if you have it siginficantly larger than 512, try 512 which is doable (I know). Maybe you can reach a little lower (like 384) but not much more I think.

At testing these things, try to always use a same "ending" so you're not depending on the audio data; drag the time slider towards the end (try until where it will play, because something like only 15 seconds before the end may not work for XXHighEnd) so then it will always end at that end of the track with the same audio data (could be silence by that time). Use short tracks because I think it will be more easy to go towards the end with the slider (so that it will work for XXHE).

Apologies for the long post ...
Peter

[CaOd]

Peter,

thanks for sharing your insights here, I have tried all your suggested routes. With or without PA, I never get ticks or any other noises at the start of a track. No anomalies whatsoever.

It only happens at the end of the playlist or at stopping, and I guess your assumption with DAC playing the last buffer is right, the it gets this transient downwards and this makes the voltage jump. At my settings, the last buffer repeats once, then the crack comes. Changing the Q1/xQ1 settings or the buffer lenghts of the DAC and in XXhe just changes the number of buffer repeats, but the crack still occurs, in some settings even worse. But it never goes away, even with very small buffer sizes.

I will check for a driver update (however the last driver update did not work with XX9.6, don't know if it would work now and if it would change this stopping behaviour), but if you could make provisions within XX in one of the next releases, would be highly appreciated!

Thanks for all your help

Carsten

[PeterSt]

Carsten,

thanks for sharing your insights here, I have tried all your suggested routes. With or without PA, I never get ticks or any other noises at the start of a track.

This suggests that you have the "crack" at the end of the track just the same without PA ?

Peter

[CaOd]

No, just with PA engaged it gives the crack, sorry for confusion / misunderstanding.

Best Carsten

[PeterSt]

Carsten,

But is there any change noticeable when you change the Weiss Control Panel buffer size (to larger or smaller) ?

Say you have Q1 at 30, Q1F at 10, SFS at 200 and then change the Weiss settings to extremes (but it must keep in playing of course);
Does this change things audibly ?

Peter

[CaOd]

I can play at Q1=30, Q1F=10, SFS=200, PA on, I set the Weiss buffer length to 256 (smallest possible value in the Weiss control panel), only change is the length of the music that is repeated once (seems like playing on buffer length), but te crack noise always stays the same (same tone, same length, same volume).  My valves show a blue burst at higher listening volume, I almost fear damaging the equipment with this burst sound.

Same behavior with XX matching the Weiss buffer settings or not. With small buffer length I receive a messag: "Asked for 15ms, received 1ms", my original settings it seemed to play 15ms.

What I notices is that when I hit stop, the music plays a second or two longer, than it repeats a second, but not the full part that I had heard after hitting stop, so it stops somewhere inbetween!?

Does that help?

Many thanks for taking care of this little issue

Carsten

[PeterSt]

Carsten,

You mentioned that blue flame in the tube(s) before, but then I thought it was merely a manner of speaking. But if this is real ...
You better quit this route ?


That you don't perceive the very last part of a track (or what you heard before at pressing Stop) is normal (and is described in a ToolTip somewhere I think).

As I said in my first response, this all doesn't seem normal;
Did you ever measure DC at the outputs of the amplifier ? You should. No, you HAVE to. But whether you did it or not, you should do it again, but now focused on what happens at the end (Stop). I am starting to suspect some kind of reversed effect, possibly created by the amplifier. Maybe some auto-bias which can cick in quickly, but which can't "cick out" so fast. So, a tube amp may be inherently protected against DC at the outputs, but to me that doesn't mean it can't choke in further processes in there.

Your "mod" of the Weiss can be about the removal of DC protecting capacitors. So, good for sound, but now it will let pass DC. Together with an amp which isn't protected against it either, things may go wrong. In your case possibly the output transformers (??) get saturated and now *that* is doing strange things when suddenly the DC stops.

I say it again, you should stop this. It looks too strange to me. And you know that I won't be responsible ...
This doesn't prevent that I will keep on helping.

Btw, I saw that your Ph Strength is at 2. Well, if I were you this would be the first I'd set to 0 before proceeding. Also use attenuation settings in XXHighEnd of over 20dBFS. Possibly it is gone then and if so, I think I can work out a solution for you. But I wonder, because so far nothing I suggested helped, and it should have.

Kind regards,
Peter

[praphan]

Hi Carsten,

I think you must follow Peter's advice on measuring the DC output fed to your speakers when engaging PA.

It seems that output transformer in all tube amps should block DC. But in my case, I always have a DC reading of +/- 1.5 V (phase strength =0) at amp binding post when hitting STOP. My tube amp has 10 uF upfront on the input signal path too. Like Peter said there must be something going on with our tube amps which does not happen in SS counterpart.

You may like to set your DC volt meter to null mode where the needle is in the center of the scale so you can read both negative and positive DC pulse. Have someone click STOP for you while you stick meter probes to the binding posts. See if you have a DC pulse. Well it looks more like very low frequency AC with high amplitude. In my case, the reading can be as high as +/- 1.9V at phase strength of 3. If you have this phenomenon, look at your woofer diaphragm. The moment you hit STOP, the woofer excursion you see can be worrisome. Mine is about 10 mm travel.

BTW, in my case, I can manage to get rid of "crackkk", "tick", "plop" at either start or stop or next. Still large excursion of woofer (at hitting STOP only) makes me feel uncomfortable. Folks in here said this is not unhealthy but it is unusual though. If I cannot find a solution to get rid of this DC or AC pulse, I will refrain from engaging PA.

Best regards,
Praphan

[GerardA]

I had the crack too at the end of playing.
Not a crack but a couple of explosions!
Just wondering if it was my transformer in the HongKong-Dac, or the tube in my preamp, or the capacitor in there or the Gainclones...
Then I changed Q1 from 1 to 15 and what remains is a short crack like removing the needle from a record.
Before it was more like pushing the needled over the record and turning the volume up.
So maybe not that much usefull, but I think it is in XXHE the solution has to be found.
And at least now I can enjoy XXHE in company of my family/friends.

[CaOd]

Before engaging PA, I had contacted the german distributor of Jadis, asking about my amp blocking DC. He confirmed, that the preamp has a coupling capacity to block DC and that the output transformers by definition do not pass DC.

I had also measured as indicated DC at the speaker output, no DC during playback with PA.

When the crack at stop occurs, I get a huge voltage peak and the speakers show huge travel. The peak is at about 1,5Volts, when normal music is playing at 200mV.

The problem is I am already addicted to the pure PA sound and cannot simply go back...

I need to find a solution and Peter, I still believe in your theory of a transient jump at the end.

By the way, PA strength always was and is set at 1 (not 2, have to correct this), the crack doesn't change with strength=0. And it does not change with lowering the Volume attenuator to -20 or -25.

I hope that we find a solution somewhere in the XXHE-DAC route...

Cheers Carsten

[PeterSt]

While typing a response, I saw this inconsistency :

I had also measured as indicated DC at the speaker output, no DC during playback with PA.

and

When the crack at stop occurs, I get a huge voltage peak and the speakers show huge travel. The peak is at about 1,5Volts, when normal music is playing at 200mV.

So I don't understand what you realkly wanted to say here !

[praphan]

Hi Peter,

I guess Carsten is trying to explain the similar experience as mine. He is trying to report his findings on DC readings focusing on the moment of clicking stop or next button.

I am not quite sure whether it is an AC or DC pulse. But I used DC null mode to measure voltage at amp binding post at the moment of hitting STOP .  I guess it is a high amplitude very low frequency AC which slowly moved my woofer diaphragm for about 10 mm.   

However, I still don't get his contradictory message about DC reading at normal playback. In my situation I always read slight mild DC swing (+/- tenth of mV) during either with or without PA playback. Never zero DC. Then at the hit of STOP the large LF AC pulse kicks in.

Hope this might help.

Kind regards,
Praphan

[PeterSt]

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 ?
If Yes, I almost start to believe there is a general problem elsewhere. So, I already started thinking like this, but when you answer Yes to this question I can be more confident about it. Btw, not a software problem, but something VERY different ... (not that I know what, but I may theorize about it).

Regards,
Peter

[PeterSt]

Thank you for all the feedback Carsten - and don't think I gave up !

On a side note and possibly important :
By coincidence I noticed myself that when the product of DevBufSize x Q1 x Q1F is too low, there will be an unavoidable loud tick at stop. And while I know you already tried a few things, for me the product is like this :

4096 x 1 x 1 = 4096 at SFS=60. So, here I have the unavoidable (loud !) tick (thump); this is WAY too low. But this works for me :
4096 x 14 x 1 at SFS=60

The message here is not that my latter setting should work for you, but merely is about the too short "buffers" theoretically *never* working. So, whatever you are going to try further, have the result of that product to be 4096 x 14 (x 1) = 57344 *at least*.
In my case this is in conjunction with a physical device buffer of 4ms. This is a dangerous one, because for me this is about 32/705600 while for you it might (will ?) be about 32/176400 (for 4x upsampled Redbook). Here is the math for this :

1 sample in my 705600 case takes 0.0000014 seconds. Two samples for stereo take 0.0000028.
My setting is 4ms;
In samples this is 357.

This very theoretically means that you should set the buffer length in the Weiss Control Panel in samples to 256 or 384 and then that part should work out the same. Together with my other settings (above) all should work out the same. And btw my Strength is 1.

So far for this little part ...
Peter