Windows 7 x64 USB Audio Clicks and Pops with Musical Fidelity M1A DAC
(and also stuttering and freezing issues with the Musical Fidelity VLink 192 DDC)
Background/ProblemI've been experimenting with just above entry-level DACs (Musical Fidelity, PeachTree, CEntrance, Benchmark) and had decided that I absolutely loved the Musical Fidelity M1A DAC for its acoustics. I would say that I have found no other DAC under $200 that I like more. My initial auditioning was performed on a Lenovo laptop running Windows 7 64 bit. However, my main PC is really an HP desktop -- reasonably beefy for its day Intel i7 2.8GHz -- also running Windows 7 64 bit. After attaching the M1A DAC to the desktop PC to a USB port on my LCD's built-in USB hub, I ran into an issue with frequent loud clicks and pops using either WASAPI or standard Windows audio out. (Frequent meaning a few times an hour.)
Normally, I do not write about PC problems into which I've run and their solutions, but this particular saga was extremely perplexing, and occupy the better of 50+ FTE hrs over 7+ calendar weeks of my testing, and somewhere around $250 in various test components and finally an additional $425 splurge on a DDC (a big investment for a $725 DAC, but I do love the sound of the Musical Fidelity M1A DAC!). I am hoping this information may help save some other poor soul experiencing similar issues a lot of sweat and tears.
The Quest for a SolutionThat started my search for a solution. I have researched and ruled out many potentially causes of issues: (Skip down to the Solution section if you don't care for the gory details.)
Update: August 6, 2013The stutter issue no longer exists with driver v1.61.0win32-64 available from Musical Fidelity's web site listed as being for Windows 8. It works fine for Windows 7. It was only a problem with v1.48 for me.
And the Solution is....Summary:
The root correlation turned out to be nVidia's power management mode. Search for "nVidia PowerMizer interrupts" and you will find many posts talking about how power mode changes in nVidia can cause a flood of interrupts leading to audio pops! (Unfortunately, if you don't know to search for that, and just search for "usb audio clicks pops" or some such, you may find an odd post about someone having success after disabling the nVidia driver... and maybe even a buried post about PowerMizer... but you will be doing much more digging...) So after going into the nVidia control panel and changing the power management setting to "Prefer maximum performance," the clicks now match the level of the old Belkin hub (once every few hrs at most) without the hub. Note that this does not completely shut off Powermizer. There are tools (and registry settings) that do that and you can find those on the web. There's a GPU-Z utility to help you monitor your GPU. This fixes most pops. It isn't a 100% solution. Maybe every 2-3 hours there will still be a pop (probably due to other issues). Nevertheless, this observation is so obscure, that I thought I would post this for the benefit of others.
I cannot explain why the old Belkin hub and the hub built into my Dell LCD helped. But the HP laptop is also an nVidia graphics chipset whereas the Lenovo laptop is an ATI graphics chipset, so that confirmed a common thread.)
Note that the pops didn't completely go away with just the M1A DAC and the nVidia fix. Including the VLink 192 DDC proved to be a 100% solution. It is a much better USB audio chipset, provides Galvanic isolation, support for 192 kHz (useful when I get more 192 kHz music), etc. There were zero pops with the VLink in place, under any setting -- from Safe to Minimum latency. (Since I am so pop-paranoid, I kept the buffering on Safe. My back-of-envelope calculation shows that Safe is only a 20-25ms lag, which I do not believe the ear can notice.) I decided to keep it. There remains one issue though -- the stuttering after the PC has been idle for a while.
Note: No longer relevant with the v1.48 update to driver
So how to fix the stuttering after idle on the VLink 192? I discovered that resetting the default audio device, even to itself, would somehow reset the driver and fix things. There's a command line tool that can set the default audio device. It works on Windows 7 and 8 (tested), so good enough for me. You can get the IAmAI/AudioEndPointController from GitHub here. I set up Task Scheduler to run it every 10 minutes, resetting the default device if no audio playing (and also force a reset when I logon or unlock a session, just in case). There is a slight drop out (but no loud click) when forcing a reset while audio is playing.
I have modified the code to provide a prettier display and to support these modes of operation by passing in:
The stutter fix also fixed the freezes with the VLink 192. With the VLink 192, the nVidia PowerMizer fix is not needed. (Previously, this was an open question, but after running for many days with PowerMizer on, I can now conclusively say that the reset stutter fix, by itself, is sufficient.)
On USB cables -- I still don't subscribe to the school that they make an audio difference assuming the DAC or DDC has good jitter characteristics. But if it's longer than a 1 meter cable, go with a higher quality one because there are some dodgy cables out there! $30 to $50 is probably OK to spend, but $100 would be a bit silly in my opinion.
One Other Possibility (Update: Jan 1, 2014)Many months after this post, I upgraded to Windows 8.1 in November 2013. Through that process, I discovered that LogMeIn Hamachi was a culprit in a DPC Watchdog Violation blue screen of death. More details here. In that research, the nVidia kernel driver also showed high DPC latencies, but proved to not cause USB audio problems. Now, in retrospect, I am wondering if Hamachi was the underlying culprit here as well for it clearly exceeded DPC time limits, which may have the effect of causing the symptoms described here. Unfortunately, I no longer have a testbed to verify.
A Final Comment About Musical FidelityI invested significant time into this problem because I fell in love with the audio coming out of the Musical Fidelity M1A DAC. However, I cannot say the same about Musical Fidelity or its US distributor (Tempo High Fidelity)'s responsiveness to inquiries. I have emailed Tempo and have even resorted to sending paper mail to Musical Fidelity in the U.K. -- and have heard nothing back.
I am also quite disappointed in the quality of the USB interface on the M1A DAC. Two points:
I will say, however, that some of Musical Fidelity dealers, including ListenUp and QAudio, are quite friendly and tried to be helpful, though the complexity of this issue was clearly not something I would expect them to actually be able to handle. This is the kind of complexity that only the manufacturer will (at least, should) have enough expertise to address.
So, based on acoustics, I will definitely stand by and recommend Musical Fidelity products (specifically, the M1A DAC and VLink 192), but for my next upgrade cycle, I will likely have a bias in favor of other manufacturers, even if they cost more for the similar performance. It's true that these are not $5000 components I bought, but having spent $1150 or so, it is fair for me to expect better. I have dealt with other manufacturers of audio gear where one of the designers is likely the person who responds to technical inquiries. This is still sufficiently high end niche products that a higher quality experience is to be expected. (In retrospect, I should have tried an April Music Stello U3 for the DDC. Honestly, I was tempted and didn't mind the ~$100 price difference though some may think $500 for a DDC to pair with a $725 DAC is silly... What stopped me was the difficulty of sourcing one to be delivered within 2 days. Now I am quite curious as to whether it's fundamentally a bug with thesycon drivers that every XMOS-based DDC may have...)
In all fairness, I suspect that asynchronous USB audio, while it has been available for approx 4 yrs now, is still immature and audio equipment manufacturers may not have enough PC expertise. But really, ignoring customers who like your product and just want to get them to work flawlessly is not a good way to keep customers... But I created this page primarily to help others who may be experiencing similar pops and clicks, so, enough said about customer service.
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