I’m certainly not going to lose my head over this review.
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There’s a big difference between noise floor and resolution. The noise floor listening to Voyager is pretty high compared to the signal, but we have enough resolution to receive the signal in the presence of many orders of magnitude more noise.
Here’s a low level (-120dB) 1k Sine (I don’t remember which release):
Most of the lower frequency crap is my computer not the DAC and the 8k is from the USB cable not the DAC. There’s a little 2k harmonic distortion, but not bad for -120dB. This plot also hints that the linearity is still pretty good at -120dB (despite some other claims.)
Here’s a -40dB 1k Sine
The noise floor is higher on this one because I was using my lower resolution (but wider bandwidth) scope. Once again an older plot, the ultrasonic noise now starts at a higher frequency and doesn’t go as high in amplitude.
Here’s an older -60dB 1k Sine
The blips at roughly 16k, 27k, etc. were also there with the scope probe directly to ground in that setup.
I though I had some of louder 1k signals, I’ll look around some more.
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Wonder who “psydave” is as he joined 4 hours ago. Could it be Armoire the tin eared measurement scientist or some other troll from ARS?
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So when the graph uses purple instead of red the DSD is quieter???
I am just going to use purple graphs from now on.
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If so, he probably didn’t like my answer. If not, he may have liked it…
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Colleagues, are we crazy? Have we lost confidence in our ears? We deal with distortions at 50 Hz at levels lower than 0.1%, and our speakers at this frequency have distortions ten times higher.
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Thanks for the warm welcome. I am an avid listener of Paul’s YouTube channel and reader of Audio Science Review for the past year or so. I’m slowly getting into hifi and came across both around the same time during my journey.
Not long ago, we hosted a garden party of about 30 people. My next door neighbor asked me what the “excellent” red wine was that she was so enjoying. Knowing that she is a wine snob, I avoided telling her until halfway thru her second glass, that it was a Portuguese blend that cost $9.00/bottle. She just couldn’t drink another sip. Somehow, “The Measurement People” remind me of this moment.
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Vaguely related: I used to drink shots of espresso with a dose of chocolate syrup. One day I didn’t get the syrup and it tasted pretty bad. I started a multiple year odyssey looking for a type of bean or a good roaster that could reliably make a good ristretto. Now decades later I realized that I was not really enjoying the “pure” coffee I was drinking and decided to put in a packet of “Sugar in the Raw” per shot. I really enjoy my coffee now and sort of regret losing the time and delight I could have had over the years by just trusting my taste 
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Ted, I do appreciate the information you have provided, I think it will help bridge the gap between your defense of the performance of the DS vs. what Amir has written. The measurements you have provided show even less dynamic range than Amir’s measurements, PS Audio’s specifications, and Stereophile’s measurements.
I fail to see how the objective performance determined from all 3 different sources justify the marketing for the DS which I stated above, which is also described as being able to “finally reveal all the music and subtle low-level details buried deep within its core.” Could you please show a measurement from any source which demonstrates the DS’s ability to resolve low level 16 bit audio? I haven’t seen the dynamic range required to do so.
Also, you seemed to be very concerned with Amir’s test setup and methodology, and yet you give no relevant information when you provide your own measurements (including the firmware version). It would be nice to see someone hold themselves to the same standard they hold others.
Sorry you don’t understand what you asked for. Claiming something isn’t what it is doesn’t make it so.
Let’s put it a different way. What’s dither? It’s adding noise above the precision to get resolution below it. The noise floor after you add dither to convert a 24 bit signal to a 16 bit signal is more noise than you get from the DS. (Tho some definitely use bad dither that’s more noticeable than dither has to be.)
In the spirit of this analogy, I occasionally drink black coffee straight, espresso, lattes with sugar, and even the occasional iced coffee with cream and sugar. However, would you be upset if you ordered a $60 cup of coffee from a company which tells you they can produce coffee so good that you can “taste what’s been missing in your coffee for all these years,” only to find out it already had 2 packets of sugar added? I think it would be more honest for that company to say hey, we produce great coffee, and it comes with 2 sugars because we think it tastes better to us, and it might to you. Espresso snobs wouldn’t go for this but I think you’d get more repeat customers than those surprised that they paid such a premium for the coffee and weren’t being told that they added sugar to it.
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Doesn’t seem you are off by much.
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The plots in Stereophile I pointed people to above get essentially the same results (not different as you claim):
E.g. figure 4 in https://www.stereophile.com/content/new-firmware-measurements
If you really care its a completely standard test that Stereophile, etc. use: -120dB Sine (as I said) into a scope with an FFT (which you could have guessed) John explains how the noise floor is affected by the FFT parameters : since John and I are seeing very similar noise floors you can read his description about how to make these plots (with an AP since that’s apparently what you want.)
JA understands how to measure the resolution below the noise floor (tho he claims that the resolution is closer to -108 (or something like that) which is belied by Figure 4.)
I’ll stop responding to you now, it’s clear that you aren’t acting in good faith.
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By the way psydave what is your user name at ASR, since you saw fit for whatever reason to use a different one here. There is no psydave registered at ASR.
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Do you have a DS DAC? Are measurements more important to you than the sound of the equipment?
I wish I knew as much as you do in my first year of audio journey. Keep it up guy.
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Then you disagree with John’s assessment of the measurements which states “I was bothered by the DirectStream’s ultimate lack of resolution with data capable of higher-than-CD resolution.”?
I don’t, I was interested in the Sprout100 and PS Audio’s upcoming bookshelf speakers, hence my interest when I saw a new review of a PS Audio product and here we are.