XXHighEnd

Ultimate Audio Playback => Playback Tweaks and Source related subjects => Topic started by: Marcin_gps on March 08, 2010, 05:04:41 pm



Title: OS latency
Post by: Marcin_gps on March 08, 2010, 05:04:41 pm
I propose that you post your current system's latencies (from dpc latency checker) as well as your hardware configurations. There is a huge dependence betweend your system's latency and SQ. The lower latency, the better SQ. It's not a placebo, believe me!
The lowest value I ever got was under XP SP3 (highly optimized, only sound drivers installed). DPC latency checker showed constant 4-5us. That was on my second, older PC (X2 3600+ @1.9GHz, 1GB DDR II 800MHz at CL3, integrated Radeon X1250, Samsung F1 HDD)

Currently I am using Windows 2008 R2. I really like this OS, since it allows for easy customization of windows features. DPC latency checker shows 20-30us. (on Windows 7x64 I got sth like 130-150us...) I highly recommend using 2008 R2, which is basically more pro Windows 7.


Title: Re: OS latency
Post by: PeterSt on March 08, 2010, 05:36:25 pm
I don't want to spoil your topic, by my latency checker shows a constant 1000us (which happens to more people). Still I use 22 samples of latency (at Special Mode, and ever tried 5 with success) which is lower than 1000us ...

Also to keep in mind (and it has been said before) : some people experience a dropping latency from latency checker as soon as XXHighEnd playback starts.

:scratching: :yes:


Title: Re: OS latency
Post by: PeterSt on March 14, 2010, 09:58:19 am
Correction :

What I said in the before post is not true anymore. I just checked, and I'm around 100us (between 77 and 117). So, the 1000 always has been so for my Vista installs, while W7 (which I never checked before) solved it. Somehow. Same system, same hardware, just upgraded.

Just to let you know, and with the 1000 the ultra low latency probably isn't possible at all. I don't know now.
Peter


Title: Re: OS latency
Post by: Telstar on March 14, 2010, 02:00:41 pm
Just to let you know, and with the 1000 the ultra low latency probably isn't possible at all. I don't know now.
Peter

Considering that i have spikes of around 1500, yes, ultra low latency is not possible in my case.


Title: Re: OS latency
Post by: AUDIODIDAKT on March 14, 2010, 05:50:50 pm
After reported issues on OS latency,

People might want to reconsider their energie settings under power options (power plan),
Low latency just asks for more energy at certain moments.
XX low asking latency settings, could wel exceed some standard BIOS or windows energy settings on several systems.
Using more energy could give that ultra low latency mode you are looking for.(without drop outs)

Just wanted to add this,
Because it seems logic to me, that asking more and faster responsiveness from OS, also takes (create) more energy (spikes).
So "balanced (recommended)" energy setting maybe is not sufficient enough, you can try to use "High performance" instead.

Peter what is your response to this matter ?

OS (or PC) Energy and low Latency are highly related in subject of glitch free playback of xx.


Title: Re: OS latency
Post by: AUDIODIDAKT on March 14, 2010, 06:18:16 pm
And Telstar,

Your system should have a latency of 7-14us (just xx playing) range, with a max of 200us sometimes.
Even when my system is at full load, it never exceeds the 300us range.

This is with a 9800gtx videocard in there full aero etc,

Try that "high performance" setting !


Title: Re: OS latency
Post by: Telstar on March 14, 2010, 07:22:42 pm
And Telstar,

Your system should have a latency of 7-14us (just xx playing) range, with a max of 200us sometimes.
Even when my system is at full load, it never exceeds the 300us range.

This is with a 9800gtx videocard in there full aero etc,

Try that "high performance" setting !

It is console with my soundcard drivers that causes these spikes.
I cannot solve the issue (tried everything together with the pretty good infrasonic support).

I have always around 55 without that.
I of course have setup the power option the way i wanted them (which is custom, not high power btw).


Title: Re: OS latency
Post by: PeterSt on March 14, 2010, 07:30:10 pm
Peter what is your response to this matter ?

Roy - Same as Telstar just said. Custom settings, but only with a good feeling guts and stuff to my conveniency. Nothing much for the low latency specifically.


Title: Re: OS latency
Post by: PietPara on March 28, 2010, 01:07:32 am
Hi,
I have a latency of around 1000 when doing nothing and when using my mouse it skyrockets. I have investigated th issue and it seems to be caused by my logitech air mouse, known for high latencies.
That's really a bummer because this mouse is great for these kinds of apps (i.e. being able to "mouse" when sitting in your comfy chair listening to music meters away from your PC-audio.

PietPara  :(


Title: Re: OS latency
Post by: PeterSt on March 28, 2010, 10:33:11 am
Yes, I'm afraid this is a commonly known issue, and applying to IR keyboards as well.

A bit of a strange solution : Keyboard as well as mouse cables can easily be extended to 15 meters (VGA monitor cables as well, if you have a decent cable). I use that myself.

I never heard someone talking about it, but maybe I would try bluetooth in your case. It could work out the same, but maybe not.

Btw, your basis 1000us is something which happens to more people, and I had that myself with Vista and never could get rid of it. After upgrading to W7 it was gone (oh, you 've probably read that from a few posts back).

Peter


Title: Re: OS latency
Post by: Telstar on March 28, 2010, 02:00:07 pm
Yes, I'm afraid this is a commonly known issue, and applying to IR keyboards as well.

Interesting.
I have the logitech cordless desktop, the most basic one, and I dont experience any difference in the latency pattern when just moving the mouse or using the keyboard (the latter is very rare). Nor when giving commands with IRTrans/Girder.

I believe that is the cr*ppy logitech software. Since long time (once it caused soo many problems in an otherwise excellent system), i never install it.
So i would sugges to uninstall the logitech software and use the built-in windows drivers.
This means no extra keys, sorry.


Title: Re: OS latency
Post by: BrianG on March 31, 2010, 09:22:22 pm
Hi chaps just getting back into XXhighend...

...and I spent about a day using Windows Performance Analyzer (WPA is a powerful set of programs that provide detailed views of system and application behavior and resource usage.) 

Long story short, I couldn't find any "one" thing that was giving all the latency in Vista (the 1000us spikes).  I came to the conclusion that it was many things happening at close to the same time?  So until someone with more know-how sets me right I'm happy to live with the latency.  However, I am just about to build a dedicated windows 7-64 machine for XXHighend (my vista machine set off with this intent but funny how it became my video/photo/card making PC as well?) :(


Title: Re: OS latency
Post by: Nick on September 21, 2010, 03:11:27 pm
Old topic, but I finally saw an occasional dpc reading of 1us today. My average dpc readings are around 2 to 2.5us after the system settles. I don't know if dpc directly tests the audio data flows of XX but I agree with comments about general sound quality improvements as the dpc's reported latency improves. Aggressiveness has reduced and naturalness of sound presentation has become markedly better, particularly as the last few micro seconds have come out of the dpc readings.

The system is a dedicated Audio build with everything cut that I can think of or have read about. Windows Explorer has also been killed which is how I normally play music.

Nick.



Title: Re: OS latency
Post by: PeterSt on September 21, 2010, 03:21:39 pm
Hi Nick - Thanks for sharing.

:offtopic:

I only noticed the similarity with my system ... I mean, I traded my AudioNote for something else allright, but a GainClone into horns ... :scratching:
Couldn't you find anything better for your horns ? (I can't, so far :)).

Peter


Title: Re: OS latency
Post by: Nick on September 21, 2010, 03:46:50 pm
Hi Peter

Still  :offtopic:  :)

I was running a pair of Audio Note P4s. I loved the 300b midrange, but could never get the extension in the highs and lows I wanted, despite LOTS of modification. Then I tried a basic commercial LM3875 chip amp design and was amazed by the sound.
The amp config I built has Stevens and Billington silver wired TVCs for volume control and two LM3875s per channel (Peter Danial kits) driving the mid and high range drivers of my Duos. I also went for 300VA R-Core transformers and Black Gate power supply caps.
I don’t need much power and the gain clones have real tube like immediacy but also deliver base extension and smooth top end. They are almost too simple to drive such expensive speakers but I really enjoy the results.

What amps do you use ? gainclones ??
Nick


Title: Re: OS latency
Post by: PeterSt on September 21, 2010, 04:23:00 pm
Yes, GainClones ... (homebrew, though not completely by myself).

One of the major issues with high sensivety horns (115dB here) is noise, that is, if you don't use a pre and/or any other means of volume control (than digital). And the GainClones are completely silent (and 27dB of gain).

Although I have been researching the "Class D" leage only, hence not specifically any Class A means (I wanted to save some on my anual 12K KWh :)) by now I can say that these little chips must be doing an even better job than I could know at buying them. I mean, back then (3 years ago ?) I wasn't hobbying with a DAC and the best sound ever, while in the mean time I do and all sounds as real as, well, real. So, real is real, and the GainClones are part of that (while it is the DAC which needs the improvement).

In the mean time though, I heard through another type of amp (also running cold, and also no Class D but *also* not a chip :)), that there's potential for vast improvement. But the amp concerned has downsides as well, so it's only theory at this moment.

I'm not quite sure what the results will be with your Audio Note as a front-end, but try to bypass your TVC. Just for trials. You could be amazed. Be careful though for a "too sharp" sound, assuming the Audio Note is NOS.

Peter


Title: Re: OS latency
Post by: Nick on September 21, 2010, 05:06:44 pm
Good to hear you are getting such excellent results with horns and gainclones, it gives me confidence in the potential of my system if I get a Phasure NOS DAC into it.

My Audio Note DAC is NOS and based on the AD1865 DAC. I’v done quite a lot of work on it, by far the biggest step was removing the mumetal potted analogue filter that comes after the I/V transformer and feeds directly into the input of the DAC output tubes. Audio note call it a "filterectomey", taking the filter out absolutely bought the DAC to life. So there’s no over sampling or filtering in digital domain (except what you provide in software) and no analogue output filtering other than the I/V conversion transformer’s bandwidth limitation. I don't have the equipment to measure the resulting DAC response but I do simile and tap my feet a lot when listening :)

The NOS and no analoge filter DAC approach works very well for me and is one of the main reasons I have been very interested in your work with the Phasure NOS DAC.
Nick.


Title: Re: OS latency
Post by: Marcin_gps on September 21, 2010, 07:13:55 pm
Old topic, but I finally saw an occasional dpc reading of 1us today. My average dpc readings are around 2 to 2.5us after the system settles. I don't know if dpc directly tests the audio data flows of XX but I agree with comments about general sound quality improvements as the dpc's reported latency improves. Aggressiveness has reduced and naturalness of sound presentation has become markedly better, particularly as the last few micro seconds have come out of the dpc readings.

The system is a dedicated Audio build with everything cut that I can think of or have read about. Windows Explorer has also been killed which is how I normally play music.

Nick.



Nice result! Could you specify what modifications have you done to Vista? Your hardware isn't top notch, so I'm pretty surprised to see that your're getting 1us...

Best regards,
Marcin


Title: Re: OS latency
Post by: Nick on September 21, 2010, 09:44:08 pm
Marcin hi,

I get the occasional 1us reading and 2-3us readings the rest of the time. The lowest sample latency the PC plays using the HiFace in Special Mode is 32 samples with Q1=1 which I think is 1 sample latency if I understand things correctly. The music plays fine but sounds better at Q1=3.

The PC has two BIOS configs and OS installations which I switch between to give a “thin” build for playing music and thick build with full H/W and OS features (eg multiple drives, networking, vista services running etc). The thin config is absolutely for music only with everything I can think of turned off, disabled or tuned to reduce background CPU load.

The thin build applies the tuning steps;

Bios, turn EVERYTHING off that is not needed essential for music and tune where possible for speed.

Disable Vista Services, I think I have ended up with 8 services that have to run.

No network - turn off N/W hardware and remove all drivers, no anti virus, windows defender, firewalls etc.

Systems settings, I’m running 2 cores (of 4), no disk sowp file, PCI lock on, turn off event logs and memory dumps on system errors - all the usual stuff.

Control Panel Applets, Disable absolutely EVERYTHING in every application not needed.

In device manager I disable EVERYTHING that I can (unused USB drivers, IDE drivers with no drive connected, PCI to PCI bridge drivers that are not used to play music etc etc)

Uninstall all unused software and start menu options, take everything out of the systems trays (clock etc etc)

Used Autoloads - turn off all drivers, auto start programs, software registrations etc that are not needed for windows (taking special care not to kill the PC boot altogether)

I overclocked from 2.6Ghz to 3Ghz (the PC will go faster but sound suffers) and run the fastest memory speed I can get from the front side bus.

Power setting configs discussed in the Windows OS tunning thread

I also kill Windows Explorer whilst playing music.

Its a bit impractical to write a build as there are literally 100s little things to turn off / disable or  config so it’s not practical. I just read as much as I could on forums and then rigorously disabled stuff if it’s not needed for music. There were a few rebuilds along the way when I overdid turning things off but mostly the windows boot option of “use last known good configuration” got me out of trouble.
I just wish it were possible to tweek the priorities of windows system processes as there is such a huge amount of raw processing power available if it can just be focused on the processes we need for music replay.

Regards

Nick.