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Isolate audio processes to a specific cpu core.

by ni-cad / November 27, 2009 8:20 PM PST


Is this possible?

I'm running windows XP Pro 64 I have good specs on this machine, an i7 quad, 12 gig of ram and an edirol UA 101 (usb) sound card. But whenever I open and close an app (well most apps) with any other audio devices running (Windows media player or my Daw FL studio for example) I get severe buffer underruns and my whole system stutters very badly until the apps have finnished their startup, during their startup process any audio playing becomes extremly distorted.

I'd like to find a permanent solution to this problem, a few things that have worked so far were, 1 using a pci sound card an e-mu 0404 (That helped) but I no longer have this card, the second solution was to raise my buffer size way up to arround 30 ms or over, obviously this is not a desirable workaround as this card can run quite happily at latancies between 3-6 ms which I need it to do during normal audio processing tasks such as running my Daw.

So, it occured to me that isolating all the audio processes to a single CPU core might stop the distortion/interuption of the audio signal that I'm expieriencing, but from here on I'm a little stumped, I can't find any trace of any processes that are linked to my sound card, or any audio devices at all infact, none of them show up in my task manager.

Isolating the apps themselves didn't work, isolating the sound card seems impossible, am I perhaps barking up the wrong tree here?

Any advice would be most welcome.



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Doesn't work that way
by Jimmy Greystone / November 27, 2009 9:53 PM PST

It doesn't work that way. Audio processes use their own CPU interrupt, which SHOULD allow them to have pretty much the highest possible priority. And if you had a dual CPU system, then your idea might work, because each CPU would have its own set of interrupts. The problem with multi-core CPUs is that they share a set of interrupts and really all that's being duplicated is the instruction processing logic. People look at them and see "quad core" and think that it's going to be the same as having 4 separate CPUs. It's not. If you had a 4-way system, the total system responsiveness would pretty much always be very high, since each CPU has its own dedicated data pathways. With multi-core CPUs, each core shares the same set of pathways, so data can still get backed up. The i7 line improves this a bit by connecting the CPU directly to the memory, instead of going through the north bridge chipset. Something AMD has been doing since the first Athlon64.

Long story short, I'd say you're just demanding way too much of a USB sound card. Regardless of what the sound card itself is capable of, you have to remember it's limited by the USB bus latency. People tend to just look at the advertised 480Mbps top speed of USB 2.0, and think that it will be really fast. They don't seem to understand that it's not really intended for low latency devices, since the origins of USB was to replace a lot of the common ports on computers at the time for low bandwidth devices. So PS/2 keyboards and mice, parallel printers, and dialup modems that plugged into the serial port. Along the way they increased the total bandwidth of the bus, but never really addressed the latency issue.

A USB sound card is just never going to be able to handle those kinds of low latencies. It doesn't really matter what you do, you're hamstrung by the limitations of the USB connection. If it were a FireWire (IEEE 1394) sound card, then you would have a fighting chance, because Apple designed FireWire to be a low latency interconnect for things like hard drives.

So you're basically looking at having to buy a PCI sound card or just living with the stutter. And since you're using XP x64, which was never really intended for widespread use (hence the fact that it was only sold OEM, so it was generally understood users would understand and assume the risks/shortcomings) good luck to you in finding a PCI sound card that has XP x64 drivers. No offense, but you've really dug yourself a nice deep hole here, and getting out isn't going to be fun.

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I see
by ni-cad / November 27, 2009 10:43 PM PST
In reply to: Doesn't work that way

So far, the only two sound card manufacturers that I've know to have 64 bit drivers (and tested myself) are edirol and e-mu, the emu I used was a pci sound card and ran beautifully, it even took care of this stuttering (though perhaps it might not help on a quad core system as you've pointed out). I can no longer use the e-mu as there's no space for it on my Gigabyte mobo so I'm stuck with the USB card:(

It just seems weird to me that even with AFX restricted to a single instance and set to lowest priority and also isolated to just a single thread of my cpu, that it should still interfear with my audio processes. Restricting AFX in this way leaves 7 threads on the i7 free amply supplied with 8 gig of ram still with all this processing and ram left for my audio processes my audio processes can't run cleanly, why is that? and why does this problem only happen with Adobe After Effects?

I'm not disagreeing with you at all here in anyway, but I do still see there being some hope, the reason is that, none of my audio apps cause this problem even with my buffer latencies set to 6 ms (which is what I normally use) everything on my system is happy with these settings except Adobe After Effects so it does look like if I can get AFX to behave itself then I may have a chance, however Restricting AFX hasn't made any improvements at all to the distortion in my audio.

Any other suggestions you have would be well appreciated, I know you feel this is a lost cause but I'm willing to try just about anything at the moment.

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You won't like the fix.
by R. Proffitt Forum moderator / November 27, 2009 11:27 PM PST

I have a friend with XP 64 and we finally fixed that. We all know that XP 64 was the love child but no maker would really support it so here how they finally cured it. They moved up to 64 bit Windows 7.

As I've seen this cure this a dozen times now this will now be my answer as anything else is just too gimmicky or unsupported.

Plan for the change.

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by ni-cad / November 27, 2009 11:46 PM PST

I agree and personally I wouldn't mind the change, however this is Adobe we're talking about here, they could screw up any OS.

As far as I can tell it's their app that's causing the problems, ok so some other of my apps are causing minor audio buffer underuns but they don't grind my sound card to a halt like Adobe After Effects does, it just doesn't make sense.

AFX it seems, just has to screw with the rest of my system and nothing I can do will help. I wouldn't hold out much hope for it running any better on windows 7, though I don't know that for sure.

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Adobe and XP 64 bit.
by R. Proffitt Forum moderator / November 28, 2009 12:11 AM PST
In reply to: lol

That explains more than you wanted to reveal. As we know how much the industry accepted XP 64, the story on 64-bit Windows 7 is entirely different. The 800 pound gorilla in the room can't be ignored this time round and Adobe is playing ball this time around.

Sitting on a good but unloved OS with less than a per cent point installed user base is going to be a painful position.

Time to move out.

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Well when you put it like that. . .
by ni-cad / November 28, 2009 12:50 AM PST
In reply to: Adobe and XP 64 bit.

I guess I have to agree, though I've found that almost all developers that support 64 bit do also support XP Pro 64, I'm inclined to say I should give it a whirl, however the stuttering problem IS the only problem this OS has caused me, driver support problems have never been an issue solely for this OS, 64 bit support has been sketchy in general, there are still a ton of apps and hardware manufacturers who are failing to make the transition to 64 bit, Adobe After effects isn't 64 bit either yet, crazy isn't it? 64 bit support won't come until the next AFX release! at present they use a workaround that involves opening multiple 32 bit instances of itself solely for rendering purposes, which sucks because the processing is still 32 bit so i's slow as hell and you can't use more than 4 gig during operating.

Thanks Adobe.

So, do these newer operating systems like win 7 and Vista really solve this stuttering and distortion when opening and closing windows/apps?

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If we dismiss the OS for a moment and talk stutter.
by R. Proffitt Forum moderator / November 28, 2009 12:58 AM PST

Let's look for sources that cause most Windows stutter. Here's my hit list.

1. Look for USB drives. Unplug. (sorry but I can't write dissertations or why at this point.)

2. Look for the IDE drives. Update the motherboard driver package the OLD FASHIONED WAY and then dive into the properties to set all to PIO. Now go back and set them to DMA. Again, this is what is done without dissertation on why.

3. Remove any CD/DVD emulators. Remove any "CD/DVD" as a drag and drop recorder software. (InCD, DirectCD, or similar.)

4. Watch out for those that run torrents. Often you find damaged OSes and owners that have wrecked the OS. Be sure not to get too close to those "tar pits of support." Take a firm stance that the OS is likely damaged goods.

Hope this helps,

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by ni-cad / November 28, 2009 1:06 AM PST

It's fresh OS install though, also the two worst culprits (apps I have installed)are FL Studio and Adobe after effects, most other windows users have been having the same problem with these two apps (programmers also). I'm pretty sure it's beyond my control, though I am running through your check list.

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The fresh OS install is your big clue.
by R. Proffitt Forum moderator / November 28, 2009 2:10 AM PST
In reply to: Thanks.

I find most skip the motherboard chipset drivers. I can't explain why. I think it has to do with many didn't know.

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by ni-cad / November 28, 2009 2:41 AM PST

Well, I didn't install the OS, that was the guy at the PC shop, I'm assuming he would have updated the chipset as he was also upgrading the pc with a new motherboard, fitting an SSD and a new processor and ram, I'm pretty confident in the guy, he's very thorough I know he spent over a day just configuring the OS.

For as long as I've had this PC I've always got these stutters, both on win 32 and XP pro 64 Operating systems, ion top of that every single part of this machine has been upgraded at least once, the motherboard, ram, processor, power supply, sound cards and graphics cards, have all been upgraded and none of the upgrades ever made the slightest bit of difference to this stuttering, I've updated the all the firmware myself before now and it made no difference, it has to be the fault of either the OS, or these apps or both.

The problem is when you talk to the developers they each of them blame the other, I'll be damned if I can get a straight answer out of them, I guess it's just going to have to be trial and error, or maybe this is the best performance these apps are truly capable of providing I don't know.

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Then why not be sure?
by R. Proffitt Forum moderator / November 28, 2009 2:50 AM PST
In reply to: Indeed.

I find "shop" installs to be among the worst. They are under the gun to install and move it out.

Why not be sure by going to the web page of the motherboard in question or

Or if you want to check with this forum, share the details so we can check.

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by ni-cad / November 28, 2009 5:55 AM PST
In reply to: Then why not be sure?
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Wow, look at those dates.
by R. Proffitt Forum moderator / November 28, 2009 6:02 AM PST
In reply to: Thanks.

Pretty fresh. And here's a nutty one.

SOME boards need the order just so.

1. Motherboard chipser.
2. MS UAA (your board maker should tell if that's needed)
3. Audio driver.

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cool, but no luck.
by ni-cad / November 28, 2009 6:46 AM PST

I don't know what MS UAA is Sad

I've installed the drivers for my edirol twice, they work fine in all of my apps, I'm pretty certain I'd be able to spot a bad driver, I've had the card for about a month and I use it regularly, it's never been the cause of any problems that I'm aware of.

Saying that though . . .

Happy I recorded the distortion (in case your interested lol). I have to listen to this any time I have audio running whilst opening or closing any apps or even windows explorer in some cases.

The problem is, I'm always listening to music, that's what I built this machine for, I'm an AV artist. So although it may sound minor you have to remember I hear this every few minuets, not only that but I'm extremely worried about what this may be doing to my sound equipment, there's about

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Listened to the MP3
by R. Proffitt Forum moderator / November 28, 2009 10:38 AM PST

Frankly I'd have disabled the onboard sound and tried a sound card. That issue and what I heard is something I've cured too many times by kicking onboard to the dumpster.

But there are are folk that insist on fixing it. For those we'll change the motherboard make and model.


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Sorry to intrude, but a forum question if I may
by MarkFlax Forum moderator / November 28, 2009 7:24 PM PST
In reply to: Listened to the MP3

Bob and ni-cad, sorry to intrude on this discussion and to go off-topic, but that link ni-cad provided surprised me.

I am used to links in these forum posts opening in new tabs or windows, so I assumed that the HTML code, (javascript, CSS, whatever), used a target="blank" element to the anchor code. So, even though I could see the link was a direct download link, I was surprised that it opened in this same web page, and not in a new tab/window. In my browser it called up Quicktime to play the mp3 but I assume that is just my own browser file associations.

Any reason why I didn't see a new page open?

Sorry, I will let you both get back to your discussion, Happy


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not at all.
by ni-cad / November 28, 2009 7:42 PM PST

I uploaded the file to a free mp3 streaming site, I like the fact that their links just open a quicktime player rather than diverting you off to any add sites.

You sign up, start a playlist, then I just copy their links out of the address bar.

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Yes I have noticed.
by ni-cad / November 28, 2009 7:57 PM PST
In reply to: Listened to the MP3

The asio drivers that tend to come with motherboards and some apps even I've found to be pretty much useless.''I haven't disabled on-board sound as yet, I didn't think I needed to as they aren't selected in any of the apps or the system preferences, I'd better remove them just in case.

This is the sound card that I use, currently

I also have one other sound card an Alesis multimix 16 which is just lacking 64 bit USB drivers, currently in Beta . .

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by ni-cad / November 28, 2009 9:23 PM PST
In reply to: Listened to the MP3

It worked, it worked I tell's ya!!1

Dissabled the onboard sound in the Bios (first improovment) this helped quite a lot, then just on a whim went through the device manager looking for stray audio drivers and found a couple of these chappies, (ATI Function drivers for High Deffenition audio) disabled them and low and behold, crystal clear audio, even when opening AFX with a buffer setting of 7 ms there was absolutly no distortion at al!!!! any lower than this and I get drop outs, but no distortion. I don't know exactly why these drivers are here, I'm assuming they're to do with my ATI Radeon HD 4870's, but why are they there? they're graphics cards not sound cards! so why do they need audio drivers? It's a mystery Happy

Thanks Bob, your one in a million mate!!

I've uploaded one of my favourite tracks for you just to say thanks.
enjoy and thanks once again Wink

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by Jimmy Greystone / November 28, 2009 10:01 PM PST
In reply to: BOB!!!!

Because all Radeon HD cards can do digital audio over HDMI. nVidia cards can do the same now. It has to do with HDMI doing both video and audio, and graphics card companies pushing to get more tasks offloaded onto their hardware instead of the main CPU.

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Everything can into focus.
by R. Proffitt Forum moderator / November 28, 2009 10:15 PM PST
In reply to: BOB!!!!

With your last two posts. Windows at its heart and soul thought there is only one sound card, etc. If you've been on this ride since DOS/Windows 3.1 you know the headaches of multiple sound card support.

What you did is proper and should hold together. I almost don't want to write that due to the jinx factor.

Sorry I didn't see this early on but if we stick to it, we often get lucky.

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