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Review and Measurements of PS Audio PerfectWave DirectStream DAC
- Thread starter amirm
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I've been experimenting with bungee cords actually. Seems as if the absorption coefficient of the variable tension really helps to dial in my bass.
No mater how fancy or expensive bungee cords I tried they all made bass rubbery in my system. YMMV.
Some people like certain kinds of distortion...
It let's you tune to taste
GrimSurfer
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It sounds like youre field of expertise is bondage and not audio, but I'm giving you the benefit of the doubt for the moment.
Are you close to answering the questions people had on your product? 'Cause we're interested to see if PS Audio and a HIFI Advocate can shed some light on why the PerfectWave DAC has such atrocious measured performance AFTER the firmware update you bragged about last night.
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Port-tuning ???
GrimSurfer
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I think that was already done by @amirm 's post Windom Measurements.
Still, it would be nice to see what data PSA has between the 2 flashes for comparison.
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Sorry for stalling. Can't help but have some fun when I can.
My original response to Adam via email discussed a little what we are after.
As Ted has mentioned a number of times, he could tweak the filters to lower the noise in the audio along with a more aggressive filter for the ultrasonics, but it simply doesn't sound as good.
This again goes back to my original email. Could Ted design a DAC that measures better? Absolutely. But what's the point if it sounds worse?
I imagine a lot have already read his post on our forums, but this is his perspective. https://forum.psaudio.com/t/another-review-of-the-ds-dac/13027
"I can lower the noise in the audio band and more and more aggressively filter the resultant ultrasonic noise: but everyone that has listened to that likes the sound less (tho I certainty expect that some would like the filtered top better.) If someone doesn’t like the DS’s sound then the DS isn’t for them, no problem, there are a lot of fine DACs out there (and TTs, etc.)
I could skip the transformer, but then the DS would integrate well into fewer systems and have more analog noise. Sure there are a lot of better transformers out there, but they cost too much for a product at this price point. I’m reasonably happy with the performance of the transformers we use. When I started the project I thought that transformers were crazy for this application and did a lot of work that avoided them, but the very first time I simply passively filtered a DSD stream with resistors, caps and a transformer I knew I was on the right track and I had to learn and changed my mind about transformers.
I’m not going to waste my time reading and rebutting the other stuff at his site, I’ve been there before and see how he treats people and how he learns. In any real conversation each party must expect to possibly change their mind. I know that I’m not going to change my mind based on anything amirm says and I know that he’s not going to change his mind based on anything I say. There’s no end in sight in such a circumstance and I don’t need to waste my time making him happy.
I wrote what I thought about his review earlier and knew full well that someone would point him to it. I have in the past privately emailed some more detailed rational for the choices I’ve made to some members of this forum, but some of those private emails were immediately posted on other forums so I have stopped answering technical questions to most people in email.
As anyone who has been here for any length of time knows I’m happy to answer questions that are asked in good faith and I think many of the above questions deserve a good answer, on the other hand I’ve answered most of the questions on asked on this thread before elsewhere (even when I knew that some of the posters were trolls.)
Some people thrive in a contentious environment and some people like a spirited debate, but I don’t enjoy either now that I’m no longer a teenager (no denigration or judgement intended about others who are different than I am) so I’m not going to read any more of this thread."
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GrimSurfer
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Stop wasting our time and patience then.
Can I assume that the relative sound differences and rankings were done with peeking rather than by ears only? If my assumption is incorrect and you tested only by sound, could you describe the controls?
graz_lag
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I read that exchange and this response from psydave. Psydave's analogy of the signal being buried in other noise is quite clear.
"... I specified in the the graphs I referenced that it is a 24 bit signal being used. You conveniently use a -90 dB dithered 16 bit signal to demonstrate your point. Dithering raises the noise floor of the signal to from -96 dB to about -84 dB (I’m not sure what dithering technique you use but this is the standard for dithered 16 bit signals). This raises the noise floor above the signal level, which is why you see such a poor representation of the sine wave of the abobe audition graph. If you do the same with a -90 dB 24 bit signal, you would see a perfect sine wave. Please correct me if I am wrong about this.
This is why it is important to specify the testing conditions as you mentioned earlier. You are comparing 24 bit signals referenced in my post to an unknown (to us anyway since you did not specify) bitrate signal in the pico output graph and a 16 bit dithered signal in the adobe audition graph. This is not an apples to apples comparison and is misleading. If you’d really like to compare with the graphs I have referenced, please use the same signal (-90 db 24 bit) for both the pico and adobe audition outputs. Or if you’d like to keep with the 16 bit, use a level above the dithered noise floor and below the SINAD, say -80 dB. Both of these scenarios should demonstrate the behavior I have been trying to explain.
I agree with you that the data is in there, as I stated above. In my example showing poor performance at -90 dB, I said: “In the first example graph at -90 dB, there is still a 1khz sine wave at -90 dB in the output.” However, having the expected data in output does not necessarily imply good performance. In order for it to have good performance, there should be the expected data and only the expected data in the output. The addition of unexpected signals is what makes your waveform look more like a sawtooth or triangle pattern than a smooth sine wave pattern, which sound different.
I’d like to apply this to a simple analogy. Let’s a take simple RGB pixel consisting of a red led, a green led, and a blue led. If one were to instruct the pixel to produce red, we’d expect only the red led to light up and we would see a red color. However, if one were to instruct the pixel to produce red and we see yellow (red and green), we would think that this is incorrect. I believe you are saying that in the case of the yellow output, because we instructed the pixel to produce red, and red is technically in the output (just use glasses that filter out green light and that would verify that red is indeed in the output), the pixel behaves correctly. My point is that this behavior and line of reasoning is not correct. I’m not arguing wether people can filter out the green with their brain and see only red, I’m saying that outputting yellow is not correct. ..."
OP
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I will up my prize to $1,000 if Ted could demonstrate that in a controlled tests with a dozen trials. To himself, Paul or anyone else that is willing to take the test.
A little story. I was explaining to my two sons how parametric EQ works in our dedicated theater. I would create a filter in bass and then turn it on and off to show them the effect. One time I did that and as I was explaining it to my sons, I realized a bit of a blank but polite look. I look at my screen and realized that my mouse had moved and so when I thought I was turning the filter on and off, nothing was happening! Yet I could clearly "hear" the effect of bass notes changing. My sons could tell there was no difference but were too afraid to say so.
My suggestion to Ted and Paul is some day.... when no one is there to look... perform a single blind test about any of these topics. This new firmware makes a good example as Paul said in the video that the difference was immediate and dramatic. Should be trivial to tell in a blind test then. My sense is that they will be totally lost, unable to tell the difference.
They don't have to tell anyone this. You too can do the test. It costs nothing. It takes little time. And it will make you hugely more knowledgeable about your hearing perception.
Until then, yes, I and others have read Ted's response. We know precisely why he thinks that way. Problem is, he is not evaluating the sound of audio products correctly so he is spinning his wheels for no reason, and wasting people's money. Had he done the tests correctly (e.g. a nice AB test) he would have realized:
1. That it is the transformer that is changing the sound and not the boatload of logic implementing a DSD DAC.
2. That the transformer effect is negative, not positive from audible point of view.
Customers are not realizing #2 because they are not properly comparing either and falling in love in their poor perception of audio.
Net, net, we rely on things we can prove. PS Audio needs to start doing the same....
I will still match you. Suggest we throw in a Topping DAC...or maybe a USB dongle converter, to make it more fun if they can’t tell.
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Hilarious, stunning actually.
GrimSurfer
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I agree, Scott. Given the high MSRP, an exceptionally capable power supply should have been used in the first place.
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