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A cheap, fast and effective way to circumvent USB IRQ issues.

24.70.95.205
Posted on July 5, 2008 at 22:49:50
Presto
Audiophile

Posts: 5957
Location: Canada
Joined: November 10, 2004
 When I was re-arranging PCI cards to try and move iterrupts around, I got to thinking... "Hey - what if got a PCI - USB 2.0 interface card? What if windows does not 'know' it is a USB device, and maps it like any other PCI card?"

So I got a NEC chipset based USB 2.0 - PCI card for $20. 4 external and 1 internal USB slots. I only need 1 - for the audio interface.

I checked the mapping after install, and the PCI card got its very own interrupt. As expected, there is nothing I can DO now to get even a single droupout... flawless performance.

Soundman - this might be your answer...

A 2nd visit to usbman.com and sure enough - usbman was already on to this, and has test reports for a number of NEC based USB2.0 - PCI cards.

Windows seems to think USB devices can be shared with practically everything else (IRQ wise). I've seen one interrupt used for five different PCI devices. For USB audio, this can spell disaster.

Cheers,
Presto

 

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RE: A cheap, fast and effective way to circumvent USB IRQ issues., posted on July 6, 2008 at 01:46:58
alan m. kafton
Manufacturer

Posts: 5285
Joined: April 7, 2000
 I hope people here truly appreciate the effort you've put into this (and other problem solving you've achieved). I can't even imagine how many hours all of this has taken (trying to solve this buss/IRQ issue, among all the others).

I am always grateful paying real folding money to someone with your talents, whenever I've had a problem over the years. Computer technology is definitely not my area....on most of these issues, I wouldn't have a clue where to start.

Bravo to you.

 

Excellent, Presto...., posted on July 6, 2008 at 09:40:02
doodlebug
Audiophile

Posts: 2022
Location: Little Rock, Arkansas
Joined: July 27, 2006
 I also fought this battle years ago when I picked up my first external sound card, an M-Audio Audiophile USB. Futzed around with it for a long time before finally installing a separate USB controller card and everything went along fine from then on.

My approach has now always been to isolate any audio interface, be it Firewire or USB, on its own controller. This ensures not only a separate IRQ but also its own set of hardware controller chips plus a separate instance of drivers.

Since computers have become pretty much commodities these days, it means that the motherboard vendors are always looking for ways to reduce parts count. This means that you _really_ don't know what a motherboard is doing with the USB controllers it has onboard. I always assume that there's squirrely things being done and never use the on-board ports for any serious work.

Glad you've confirmed this.

Cheers,

David

 

RE: A cheap, fast and effective way to circumvent USB IRQ issues., posted on July 6, 2008 at 10:41:55
SeVeReD
Audiophile

Posts: 944
Joined: March 25, 2001
 Good job figuring out it's on its own irq. I have all but one usb port shut down; don't have any problems showing up... but it could still be sharing an irq with another device...I'll have to hunt in my vista for that info again and see.
This has me wondering if I should pick up one of these:

Acer Aspire 9500 laptop Pentium 1.73GHz w/ 2 gigs ram, Vista Premium 32 bit, WAV/CUE files on Hard Drives via firewire, XXHighEnd player Q1 14, player priority nothing,thread priority high; Stello 100 USB-DAC nos

 

Presto..........So are you saying................., posted on July 7, 2008 at 22:35:18
xsparky
Audiophile

Posts: 50
Location: Pacific NorthWest
Joined: November 1, 2005
 Sorry for re asking what I think you are saying.

By Installing an external PCI to USB2 card and plugging in your USB Interface or dac,(not using the mother board USB ports) you have eliminated drop outs from your USB music playback.

This is the last problem I seem to have sometimes. Some days no drop outs at all, and other days just a few drop outs.

Thanks.

 

Let me clarify, posted on July 8, 2008 at 14:22:09
Presto
Audiophile

Posts: 5957
Location: Canada
Joined: November 10, 2004
 Xsparky:

I put a standard PCI card into my computer that has 4 USB ports on the back. In essence it is a PCI hardware USB controller.

Since it is a PCI card, Windows was quite generous when it was assigned this specific devices interrupts. The device itself requires more than one interrupt. 3 to be exact. One for the PCI card, one for the standard USB controller and one for the enhanced controller. I believe (I can't rememeber, I am not at home right now) that the PCI card itself was given one interrupt and both controllers (standard and enhanced) were given another. Both interrputs were unique from all others on the machine. The fact standard/enhanced was shared probably does not matter - especially if you are only using one or the other (aka ONE USB device).

When "onboard" USB controllers are assigned, they are treated differently by windows, and interrupts are almost always shared - sometimes four or five shares with such items as SATA and graphics controllers. Maybe keyboard and mouse can share with these devices, but not a USB audio device that uses a much higher data rate perhaps? I am speculating here.

In any case, yes. I did use a PCI-USB card, but *not* external.

I used an INTERNAL PCI to USB card.

And yes, it worked for me, for David here (Doodlebug) and it is a recommened tweak / troubleshooting trick by usbman.com. Usbman even did thorough testing of different PCI-USB interfaces, and they all got 100% performance results. They even make a PCI-e to USB card now.

This may the final answer for many who are having USB dropout issues in XP. Either that, or go to vista!! ;)

I would be curious to know how one of these cards works with Vista, and how Vista assigns IRQ's to it... Alas, another test to be done!

Cheers,
Presto

 

RE: Let me clarify, posted on July 8, 2008 at 16:30:24
Dynaudio_Rules

like this??
Karma Means Never Having To Say Your Sorry

 

Thanks Guys......Now I Understand......Off to my computer parts store., posted on July 8, 2008 at 21:22:23
xsparky
Audiophile

Posts: 50
Location: Pacific NorthWest
Joined: November 1, 2005
 I will order one with the NEC chip set from NewEgg or the like. It is a cheap tweak. The occasional dropout seems to be my last annoying Issue. I am using the Trends UD10 USB to SPDIF converter, then to a Musical Fidelity DM25 tube dac with very good results.
The only other direction I am contemplating is the Offramp Turbo 2 or go whole hog with the Cosecant or Crimson.
I'll try the USB card first.
Thanks!

 

Yeah -looks good. Here is mine., posted on July 9, 2008 at 22:40:51
Presto
Audiophile

Posts: 5957
Location: Canada
Joined: November 10, 2004



My audio device is on the USB Hub that corresponds to IRQ 17. I get this information by looking at the device manager, devices by connection. When you look at a USB Hub, it tells you what (if any) device is using power under the power tab. Then the resources tab tells you the interrupt so you can make the correlation. Then you can tell if you have a unique or shared IRQ. Simple as punch! ;)

Cheers,
Presto

 

RE: A cheap, fast and effective way to circumvent USB IRQ issues., posted on July 12, 2008 at 10:59:23
audioAl
Audiophile

Posts: 1462
Location: So. Texas
Joined: December 16, 2007
 Here Hear!! I dont use USB, yet. Kuddoo's to you.
Now I Understand

 

RE: A cheap, fast and effective way to circumvent USB IRQ issues., posted on July 12, 2008 at 12:52:30
alan m. kafton
Manufacturer

Posts: 5285
Joined: April 7, 2000
 Try and implement a Firewire solution, especially for playback purposes (USB connections for outboard storage are o.k.). While USB is the ubiquitous connection of convenience today, Firewire (which has been used for years in the pro world) has no frequency/latency limitations, especially in terms of ultimate hi-rez file playback.

There are those that will squawk at my statements, as they feel that USB is "just fine" for their purposes (especially since most ripped playback occurs at 16/44.1), but I waited and waited, for almost 2 years, for both USB gear and connectability that would offer me hi-rez playback without limitations. It still ain't happening. But it's easily available in the pro sector, which is where I found my solutions.

So, don't use USB "yet". Firewire itself is quite inexpensive, and the high quality Firewire DAC/processors available will not break the bank. My 3 cents.

 

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