[ELK Hoofnotes: This post has been deleted as it, and Dan’s subsequently posts, were inappropriate and disparaged a fellow forum member. I deleted a number of posts by other members which were appropriate, but responded to Dan and no longer have a context.
Let’s continue the discussion with Audiobill’s post which, while responding to the deleted thread of posts, raises a productive question.]
Guys, a little perspective…
If this was so important, wouldn’t the beta testers have picked up on it?
An excellent, real-world point. I certainly would expect so.
Our worst case scenario is that an already excellent sounding DAC will get even better after Ted squashes the bug. My expectation however is that the change will make no difference to us as users. There are many things we can measure, but our senses cannot hear or see, and make only a theoretical difference. Selfishly however, I would be delighted if the DS got better. 
As an aside, I appreciate Ted’s approach of “I’m glad JA found a bug. Now I can fix it.” This is, of course, how science and engineering should be done.
Indeed. And hopefully everyone calms down a bit. Here’s the thing. JA does testing that we do as well as testing we don’t, as others will also do different tests, like those from HiFi News. We vetted DirectStream through a battery of tests, tests we normally do, others that were new to us Ted introduced, etc. Are these tests conclusive in every respect? Probably not. I can imagine along the way others will find tests we never thought of. That’s the nature of engineering, testing and working with cutting edge products as we do.
Ted’s approach is very refreshing. He takes little of this personally and for that I am in admiration. We all learn.
The small anomaly John found has no bearing on the sound quality. Ted’s already sent us a version of the FPGA with it ‘fixed’ and neither Arnie nor I can hear any difference. We had a long conversation with John that discussed his methodology and conclusions and John agreed with us that it was not really useful to telling how the unit sounds or performs. However, John’s a dedicated scientist in that he likes to make sure all units are subjected to an identical test procedure, relevant or not, so one can draw an accurate baseline between all units tested. That’s what he did.
DSD is different than PCM and applying the same set of criteria to a DSD device as is come to be accepted with a PCM based system isn’t always going to tell you the whole story or even a story that has any relevance to the real question of how it sounds. Over time, and as more DSD based DACs enter the marketplace, you’ll see John’s measurement methodology change.
The real issue with a DAC concerns resolution and linearity. Both Ted and I are not only comfortable with DirectStreams performance in these areas, but rather proud. Few devices on the market can claim anything near its performance level.
Thanks for the good open dialog.
Technical measurements are an interesting topic. Using technical measures, you can often measure very small differences and with great precision. You could measure 100 different attributes between product A and B, run statistics and present the differences as significant at 95% confidence. That said, just because you can measure differences between two products (and call them statistically significant) doesn’t mean these differences will translate into a noticeably different consumer response.
John has been consistent with his testing, which is critically important if one is going to compare results across products.
I find fascinating that DSD and PCM produce different results which may or may not be meaningful. We will eventually get it right; we have gone through the process of determining what measurements matter in audio before. It can be slow and painful to watch however.
I am just relieved no one nit-picks my posts as reviewers do products. I am certain there are many bugs to be found.
Paul McGowan said Indeed. And hopefully everyone calms down a bit...The real issue with a DAC concerns resolution and linearity. Both Ted and I are not only comfortable with DirectStreams performance in these areas, but rather proud. Few devices on the market can claim anything near its performance level.
That was the bug, with very low level signals the FFTs were weird since the low bits were mangled. You can’t see it well in the small display in the article but the result was that the 2nd, 3rd and 5th harmonics were louder than the 1k tone. The fix moves the energy back to the fundamental.
And it also fixes the sinewave distortion? Is it also a juicer?
Ted Smith said That was the bug, with very low level signals the FFTs were weird since the low bits were mangled. You can't see it well in the small display in the article but the result was that the 2nd, 3rd and 5th harmonics were louder than the 1k tone. The fix moves the energy back to the fundamental.Please pardon me if I missed something, but is this 'fix' available in a firmware update that has been released, or one that is yet to come?
The changes made by the fix aren’t audible to any of the six or so people that have listened so it’s not worth going thru the pain of a release (which includes extensive listening.) The fix will be in the next release of the FPGA which hasn’t been scheduled.
A perfect plan.
I had the same impression as Art Dudley of the DS before I installed the new firmware. Before the update, it did not have the heft of the MK11. There was nice detail and a better soundstage but the DS at that time was like decaffeinated coffee, it just did not quite get the juices flowing.
Paul and Ted, will a FW update be provided to JA so he can remeasure the DS in a later issue? I’ve seen that sometimes JA will remeasure equipment for one reason or another. Granted from the sound of it it will not be an audible change, but if it improves the measurements it might be worth considering. There’s always the measurements first crowd.
We can reproduce his measurements so we can verify that we have really fixed things. I’ll let Paul more directly respond to your question.
We will ask John, at one point, to re-measure but it’s up to him if he has any interest in doing so or not.
Regardless as to whether JA remeasures after the fix it would be useful for Paul & Ted to publish their measurements in this thread.
When I find the time I will run a clean set of measurements and post the relevant ones. A hassle is that I use different equipment than JA does so I’ll probably have to show the before and after with my tools. I’m under water at the moment
May still be useful if someone else at PS Audio can publish the before and after measurements. It might stop a lot of the negative
chatter going on in other forums - see link below.
Sigh. Just what I was assuming would happen. The “measurements mean everything crowd” will now happily trash the DS and use this to prove that everything PS Audio has done is nothing but hype. Ticks me off. I’m an engineer for God’s sake and I’d be the first one to tell you that measurements still can’t tell you everything. I don’t want either Ted or PSA to rush this, however. I’d rather Ted take his usual method of being very deliberate about designing and testing the next set of improvements before it’s let out into the wild. On the one hand I think it would be a hoot to release the FW fix that cleans up these measurements but has no audible impact - I’d love to see how the measurements crowd would respond to that! (Hmm, Ted maybe you ought to run a set of measurements yourself with that variant just to expose some of the problems with measurements…). But it would be much better IMO if the next version cleaned that up and provided some real improvements in code optimization etc.