Will try this out!!
Ted,
I just canāt visualize your DSD upsampling, or can but it doesnāt do anything.
Say you have 10 0ās in a row, then you x20 those and have 200 0ās in a rowā¦ in the same time period. The transition to a 1 happens at the same timeā¦ seems equivalent to meā¦ Does this just help placing incoming PCM into the DSD timeframe buckets?
Orā¦ ut oh-- thereās a 1 coming up, start progressively slipping in 1ās to smooth the transitionā
This is probably wildly inaccurate (my post). ;D
There are a couple of approaches to thinking about upsampling, but hereās a 30,000ft view:
In either PCM or DSD the canonical (purely) upsampling process is zero stuffing between the old samples to get to the new sample rate and then low pass filtering (at 1/2 of the old sample rate) to get rid of extra images (āaliasingā) in the result. Just as doing filtering in PCM requires more bits for the intermediate values than the input has, doing that filtering on the DSD will cause the samples to have more bits too. For either of these processes, when you are done you need to narrow the results to the desired sample width without loosing accuracy - in PCM you use dithering and in DSD to get back to one bit without loosing accuracy you need to run a sigma delta modulator. (Thereās actually a continuum of possibilities between PCM and DSD ā¦)
The reconstruction filters mentioned above do smooth the transition, but to have played the original PCM (or DSD) that transition would have been smoothed anyway (by the DACās upsampler and/or itās final analog filter.)
In DSD the noise thatās introduced by the noise shaping will completely obscure any particular bit transition anyway so thereās no need to worry about a given bit. The remodulation process will keep the density of 0 to 1 bits the same but predicting a particular bit at any point in time is next to impossible without simply running the modulator and seeing what it gets.
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I tested DirectStream DAC with MacOS and DSD256 shows up there. All we need is PS Audio updating usb audio driver on Windows. Itās still 1.61 and I donāt understand why they canāt just send newer version out. Version 4 came out for a while already.
You didnāt get the DS to tell you that it was receiving DSD256 - it canāt. You can downsample DSD256 in Windows the same as you are on a MAC. It takes more than a software update in the XMOS and on all sending OSās to get DSD256 to the FPGA. If it were that simple PS Audio would have done it a long time ago.
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What I donāt understand is newer driver in MacOS, Linux and all others can work with it so what would make it so hard to release stable driver version for Windows 10. 1.61 is old Windows 7 and long gone from market. Windows 10 needs to get driver 3.xx or 4.xx for stable audio playback (2.xx also work but 3.xx is designed for Windows 10 better).
Please do something about Windows support. I know some clients who asked for driver update but no avail for years already. Your DAC is high quality and it deserves newer driver support.
What issues with stability are your clients experiencing inside Windows 10? Upon connecting to the USB port for the first time, Windows 10 automatically recognizes the device and installs the appropriate driver. Iāve never experienced any issues with stability with the default driver. PS Audio does provide an additional ASIO driver here if you havenāt already installed it.
Supporting DSD256 is more than just updating a driver. Iām not sure if youāre aware of this.
I have a few issues with DAC using v1.61 driver like MSB, Oppo, etc. in Windows 10. Those issues are resolved after updating driver to most recent version. For now I can try to setup workaround but I hope they can get better driver. You can request a new driver implementation based on what youāve done before. Maybe some small cost to pay but it should be done for productās like DirectStream DAC. Truly unacceptable to use 1.61 driver in 2018.
What issues were you experiencing with the v1.61 driver? Can you be more specific?
playback instability. sometimes canāt play or device is hanging. Most companies already fixed this issue with driver 3.xx or 4.xx already. I wonder what took PS Audio so long. I hope one day newer XMOS driver will be shipped and PS Audio users will be very happy with it instead of being stuck up with 1.61 driver implementation from 2012.
This is the first time Iāve heard of anyone having an issue where playback canāt begin or a device is hanging via USB. The only times this has happened to me is when something else on my PC is using WASAPI exclusive mode (and playback canāt begin) or Iāll have a small hangup if I want to play a track and itās on a harddrive that Windows has put to sleep. So I have to wait 5 or 6 seconds for the harddrive to turn back on before playback can begin. None of this is related to a faulty driver. If I were you, Iād try and re-install the driver and if that doesnāt work, Iād try a different PC. There havenāt been complaints here with the driver as youāve talked about and as you point out, the driver is many years old. I would have expected to see at least a few others complaining over the years if this were a widespread issue. It could very well be an issue related to how a particular PC is setup. Again, try to reinstall the driver and/or a different PC.
Well, I heard this from a few people already. And many people addressed about Windows 10 driver fix in XMOS in years back too. I believe itās not too hard to update USB audio driver because I experienced a few issues with 1.61 drivers from a few DACs before and updating driver fixed those issues. Maybe not so much in PS Audio but itās not non-existent.
Hereās one guy who reported recently. If USB audio driver is updated, he probably wonāt have to post this.
He was using the wrong driver.
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I see. And I saw the case of PS Audio USB board hanging up myself with one of older DAC. I need to turn off PS Audio DAC, unplug power cable and turn it on again to fix it.
It seems using ASIO output is the only way to reduce issue with it and some apps still refused to work with its ASIO driver or have stability issues too.
Please, just update USB audio driver. Why is it so hard? Donāt you see other companies pushing new drivers to improve USB audio performance from time to time?
The newer XMOS/Thesycon drivers didnāt fix any of the problems that were reported and they added clicks and pops in certain circumstances. The drivers that PS Audio provides work with their DACs (whether ASIO, WASAPI and DS). FWIW the some of the various Microsoft drivers that now come with Windows 10 work fine and others donāt. Sometimes āDonāt fix what aināt brokeā is the best approach.
Can you give us a reason why you wonāt ever update USB audio driver for years? Whatās the constraints to update PS audio driver to newer version more than donāt fix what aināt broke? I wonāt ask if thereās no people telling me about its issues whether you admit there is one or not.
Iām not claiming that there are no bugs in the overall USB implementation for PS Audio devices (and PS Audio has fixed some of them) but as I replied earlier the newer drivers didnāt fix those bugs, added clicks and pops at times and didnāt provide any new function that was needed. The earlier new drivers purported to provide Native DSD as well as DoP, but that caused people a lot of problems. Note that Iām not the one that decides this at PS Audio but I have rejected some driver updates that added bugs.
Fixing bugs is important, but needlessly updating things just because newer version are available isnāt wise - it adds needless instability, requires more dev work and more support work.
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Could you tell us list of driver version youāve tested so far and what bug was added during testing for reference? I want to see and compare with other USB DACs.
No, I canāt. I tested them at the time but didnāt record the version numbers. (Iām not an employee of PS Audio and I donāt have access to their records (if any.))
On the other hand I do know that āWindows 10 needs to get driver 3.xx or 4.xx for stable audio playback (2.xx also work but 3.xx is designed for Windows 10 better).ā isnāt correct.