| High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running |
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Message | Subject:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | yep
Prenoob
Joined: 11/01/2013 05:03:23
Messages: 16
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| Longtime Firepod user, bought an 1818 VSL looking for a USB replacement so I can upgrade my laptop rig (getting hard to find laptops with firewire these days...)
I've been using this rig with a Firepod and other interfaces (including USB) from Line 6, MOTU, M-Audio, and Zoom with no problems, for years. But AudioBox does not seem to get along well. Details...
- With the AudioBox hardware disconnected or turned off, DPC latency is happily around 50-120µs, absolute max 502µs. So far so good.
- I turn on the Audiobox hardware (with the system tray utility disabled/off), and DPC latency increases to around 500µs average, max around~1500µs. Not awesome, but should be usable. Recording in REAPER seems to get very occasional and very mild crackles. Not a deal-breaker yet.
- When I run the AudioBox VSL utility/software, DPC latency shoots off the charts. Average bouncing around 800~4,000µs, max upwards of 10,000µs. Sound quality is completely unusable: glitches, pops, crackles, digital space-monkeys, the whole shebang.
- Turn off the AudioBox, and DPC latency goes back down to happy green lawn.
I have tested this:
- On multiple USB ports with no other peripherals or removable drives connected
- After following the Presonus PC optimization guide
- After complete AudioBox uninstall/re-install per Presonus instructions
- With all external devices disconnected and all of the following hardware simultaneously disabled in Device Manager: all network cards, modems, wireless, bluetooth, smart-card readers, firewire, onboard audio, fingerprint scanner.
- All other software and system-tray services disabled (just AudioBox and DPC latency checker running)
Same symptoms. The only thing that seems to affect DPC latency is AudioBox hardware (almost usable) and AudioBox software (terrible).
System details (yes, I know it's old and crappy, that's why I'm looking for a USB interface, so I can ditch firewire and get a new machine):
- HP Compaq 8510w laptop factory-build
- Core2Duo, 2 Gigs Ram
- Win XP Pro SP3 32bit
Is this a defective unit? Is the DPC spike from AudioBox hardware normal? Does the massive spike when the software is running provide any clues?
thanks in advance for any help. Trying to decide whether to return this. This message was edited 2 times. Last update was at 11/01/2013 05:34:47 | Subject:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | perceval
Presonic
Joined: 30/11/2012 19:37:03
Messages: 283
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| Did you bother to read around the forum or thought you must be the only one with this problem before posting?
A short read will bring you some information. You might even find the recent announcement from Presonus regarding the USB VSL series...
Just saying... | MacBookPro 15' late 2009, 2.4mHz, 8G RAM
OS X 10.9, 10.8, 10.7
Presonus 1818vsl (1.2.2 not beta anymore but still sketchy),
Yamaha mixer
Art USB Dual Pre
Samson, Blue mics
Logic Pro, Reaper, S1 Pro (can't use it in my case because of a lack in MIDI support)
Yamaha DXT700
Superior Drummer, Addictive Drums, Drumic'a! | Subject:Re:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | mech2161
Presonic
Joined: 11/06/2012 17:51:02
Messages: 756
Location: Morgantown WV
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| Easy now, he's new here.
| | Kevin | Subject:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | yep
Prenoob
Joined: 11/01/2013 05:03:23
Messages: 16
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| perceval wrote:Did you bother to read around the forum or thought you must be the only one with this problem before posting?
A short read will bring you some information. You might even find the recent announcement from Presonus regarding the USB VSL series...
Just saying...
Yes, I did read around the forum for several hours, and followed all the instructions/suggestions I could find.
I did not find any specific reference to whether it was normal to see drastic increases in DPC latency while the AudioBox hardware was connected.
A piece of information I was hoping to find in my searches, but was unable to find, is whether the DPC latency spikes from Audiobox are normal. I figured that posting my own results might at least help future forum-searchers and/or suggest some clues for investigation and troubleshooting. This message was edited 1 time. Last update was at 11/01/2013 17:34:11 | Subject:Re:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | yep
Prenoob
Joined: 11/01/2013 05:03:23
Messages: 16
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| Okay, so after much more searching for solutions/causes...
I did stumble across the relevant 'announcement' (via Gearslutz, since it is in the 'General VSL' forum, which I somehow missed):
http://forumsarchive.presonus.com/posts/list/32657.page
We have been made aware of several issues regarding noise and pops and clicks when using the AudioBox VSL with Mac and PC systems. We are actively investigating these reports to confirm the reported failures and look for possible solutions. As we are investigating this, we do not have an estimated time for solutions, we ask that you be patient knowing that we have made this a top priority with our development team.
So it sounds like either a driver or architectural issue, with no immediate solution. It was good of Presonus to acknowledge this, but it sounds like it took a long time.
I still do not see anyone specifically citing the symptom of drastic DPC latency increases when AudioBox is active, and some of the reported symptoms/conditions seem different but related to what I am seeing. That is not generally good news, in my experience.
A couple of things I can add to some of the stuff floating around out there, for the benefit of people like me who were searching for technical detail rather than user rants and re-statements of vague symptoms that can occur in any setup with any DAW system...
- The problem is definitely not isolated to USB 3.0 ports, nor to cheap/nonstandard system configuration: the PC I am using is older, but it was very very expensive when I bought it, and I bought it specifically because of rock-solid DPC latency and well-integrated hardware. It has worked happily for years with firewire interfaces from Presonus, RME, and MOTU, and USB interfaces from Line 6, M-Audio, Zoom, and others. There are no USB3 ports on it. It has worked, and still works flawlessly at low-latency with a variety of FW and USB hardware on a variety of DAW platforms including Reason, Ableton, Sonar, Nuendo, REAPER, and others, with normal DPC latency around 100 and typical round-trip latency around 8-12ms, depending on hardware and software. It's not the computer, and it's not specific to USB 3.0.
- The problem is not universal. I got the Audiobox working just fine on a PC desktop, and not-quite-perfectly, but with a minimum of glitches at higher latency and/or lower sample rates on a different laptop.
- My symptoms persist regardless of latency or sample-rate. In fact, there appears to be no appreciable difference in performance when using, say 44.1k sample-rate at highest latency settings versus 192k at 256 buffers. Once again, not the computer.
- Disabling anything and everything does not seem to help-- I get the same apparent symptoms when running with all network adapters, modems, external drives, card-readers, bluetooth, wifi, fingerprint sensor, etc disabled in device manager, as I get when web-browsing over wifi with a bluetooth mouse and running multiple programs, recording to a USB drive. Zero apparent difference in symptoms, which jibes with my experience using a Firepod, for example: I do that with wifi and bluetooth and all of it running and actively using other programs, with no problems, and no spikes in DPC latency. (You can do that with well-integrated hardware, contrary to popular sentiments that you can't record with wifi, etc... I can record video of web-browsing via wifi and bluetooth while recording with DPC Latency Checker running if anyone doesn't believe me.)
- Of note is the fact that the problem does seem to have some intermittent, comes-and-goes quality, which suggests something software-related, at a higher level than simple cause.
One thing that I suspect is important, but that I have not been able to find any kind of detailed technical info on is how exactly the 'VSL' feature works: it appears to be processing done on the CPU, applied to data transferred over the USB bus, but somehow either separate from or parallel to the 'real' IO (?). That is to say, if I understand the scant information I have found, the 'VSL' feature is not purely a GUI for hardware DSP, where the Presonus 'Box' is doing the VSL effects and signal-processing, but that VSL is actually processing the audio in the computer and returning it to the AudioBox at lower latency than it is doing with the 'real' audio going to the DAW software, or somehting like that... is that about right?
If so, that seems like either a stroke of genius, or a giant red flag, or both. I'm speculating here, but it suggests that Presonus might be doing something a little bit outside strict USB and conventional engineering standards, and might be in danger of outsmarting itself with a 'hacky' approach, one of those 'cobble stuff together until it seems to work' type things... If that is the case, then I suspect the only universal 'fix' might be something like a separate driver/firmware package that kills the VSL functionality and makes the AudioBox work more like a firepod. I'd be perfectly fine with that, but I think it might be a big hit to Presonus' marketing strategy, to say that some people get a high-quality USB interface with VSL, and others just get a high-quality USB interface: try it both ways and see what you get.
More ominous is the possibility that it may not be fixable via firmware/driver....
I'm a big fan of Presonus hardware, and I have recommended it to a lot of people, who bought it on my recommendation (I carry some undeserved clout in some weird little circles). I have my quibbles, but front-mounted, per-channel input combo jacks with individual gain-knobs and high-quality preamps and AD is exactly how I think a portable audio interface should be designed.
I was hoping for a USB Firepod. That's all I need for a portable laptop rig, and I prefer the front-facing Presonus knobs-and-jacks layout to RME or Roland's more feature-laden and menu/software-based configuration (never mind the price). I fear that Presonus may have tried to over-promise on this unit, and might have hamstrung a good piece of hardware with an iffy feature-set. (The sound-quality is phenomenal, when it's not crunching and crackling and popping and sending ghostly digital space-monkeys).
I think I'm going to return it on Monday, because my window of opportunity to do so is short, and because I need something reliable. The fact that people have been complaining about this for over a year, and that Presonus has 'officially' known about it for two weeks, and that otherwise silence, is not a good sign. If they had a fix in the works, we would probably have heard a whisper of it by now. | Subject:Re:High DPC Latency, Crackles, pops, and distortion when AudioBox VSL utility is running | Monolithent
Supreme Baconator
Joined: 28/07/2010 18:47:25
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| Here's that whisper.
They are working on a fix but they do not announce it in case they can't deliver on the estimated date. It's just policy.
But with that said, we understand. You've gotta do what you've gotta do. There's no shame in that nor will we not be willing to help with anything you do get working.
Good luck with the new hardware. | http://support.presonus.com
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I have found VirtualBox forum posts referring to DPC Latency on the host, but not on the guest.
