Sonore MicroRendu Hardware Teardown and Review

[fas42]

Nothing.

You manufactured it. It is not resident in either file.

Manufactured? The two files are different, in the way I described - one is the original, the other is meant to be a close replica. I choose to call the fact that the copy is not perfectly identical to the original, "distortion" - the query is then whether that difference, if you prefer not to think of it as distortion, is audible?

 

[fas42]

Comparing digital to analog (redigitized) it is unlikely to produce a true null ( null = no difference) due to amplitude differences, a few milliseconds of overall time difference, etc. Being off by even one sample time makes a mess. You have to fool around with it and see what happens.

Analog doesn't have "sample times" so you are unlikely to be re-sampling the analog at the same nanosecond as the sample that was decoded. Even with "no difference" you will see differrence. Ready to give up yet?

To do the comparison seriously requires a lot of grinding, much more than Ray has indicated - DiffMaker was an attempt to automate this process - and it's highly flawed. Huhhh? Well, when I first got hold of the program I tried deliberately distorting an original waveform in a very simple way, to see how it behaved ... well, misbehaved is a better term; I was never able to coax the program to even hint at how I had damaged an audio file - a complete failure, was my appraisal.

 

[amirm]

No ... and relevance?

The objective analysis says these files are as close to each other as bottles of water are in a six pack. Yet you think they are wildly different. So if the answer is "no" to water bottles, you should re-think your conclusion in this manner too.

 

[amirm]

In my experience, diffmaker crashes 9 out of 10 times. I have not been able to use it for anything despite trying a few times. It is an old tool that has not been maintained.

 

[manisandher]

Thanks for all your help guys.

FWIW, I hear a difference between files #8 and #9 too. I'd describe the difference in exactly the same way that I described the difference I initially heard between #2 and #3 (before I started doubting myself). Incidentally, file #8 was with the microRendu and file #9 with the Phasure Mach II - everything else in the chain remained exactly the same.

I remain totally open to the possibility that the difference I initially heard between #2 and #3, and the difference I now hear between #8 and #9 are totally inside my head and don't actually exist. But I'm confident enough that this is not the case to make a decision on which digital transport to keep and which will go on eBay.

On a final note, I'd just like to say that I think the Chord 2Qute is a great DAC for the money...

Mani.

 

[manisandher]

In my experience, diffmaker crashes 9 out of 10 times. I have not been able to use it for anything despite trying a few times. It is an old tool that has not been maintained.

Thanks Amir. I think I'll give it a miss.

Cheers, Mani.

 

[ceedee]

DiffMaker was an attempt to automate this process - and it's highly flawed.

It seems that any measuring tool (such as the Foobar ABX plugin) would likely be "highly flawed" when compared to the only "constant" you trust: your own perception.

As human perception is actually the largest variable in the equation, this mindset sends you on an endless journey of chasing your tail – as audiophiles are wont to do, of course.

 

[RayDunzl]

Manufactured?

Let me manufacture a difference:

A and B are sonically identical. They also measure identically via FFT. They just don't look the same.

DIFF AB is the simple sample by sample difference. The difference is not part of either A or B. It is also sonically different, and measures somewhat differently via FFT.

 

[Blumlein 88]

There is not enough difference for you to hear anything.

In my experience, diffmaker crashes 9 out of 10 times. I have not been able to use it for anything despite trying a few times. It is an old tool that has not been maintained.

Well, I only get about a 30% crash rate. When it works, it sometimes automates a complex process to get results hard to obtain otherwise. When it shows a deep null depth I have never seen it be anything other than truly a deep null. Now sometimes you can tell two files null pretty deeply and it gets tripped up. Shows something goofy like a 3 or 5 db null. Sometimes you can figure out why (usually silence or low level noise at the beginning of a track). So if I get good results I feel pretty firmly they are real. If not, don't worry about it. I use it as something of a filter. If I get goofy results don't worry about it move on. If I get results that make sense it has done something very difficult to do manually. It has time shifted, drift and level corrected two files to allow a comparison of how similar they are.

Not the greatest endorsement, but a reasonable one. So when I tried track 8 vs track 9 and get 93 db left and 97 db right, well there is not much difference. Likely down in the noise floor of the analog system in use.

 

[manisandher]

So when I tried track 8 vs track 9 and get 93 db left and 97 db right, well there is not much difference. Likely down in the noise floor of the analog system in use.

In your opinion, would it be worthwhile my trying #8/#9 vs. #1 in diffmaker, or do you share Ray's doubts on it being doable?

Mani.

 

[Blumlein 88]

In your opinion, would it be worthwhile my trying #8/#9 vs. #1 in diffmaker, or do you share Ray's doubts on it being doable?

Mani.

I got 33 and 37 db doing that 8 and 9 vs the original.

The reason having done a good bit of this is frequency response. Even tiny FR differences will cause issues. That little difference even at high or low frequencies will throw diffmaker off. It has a provision to adjust for FR differences, but it also is problematic to get working correctly. Without getting too complicated knowing at least in principle what Diffmaker does it isn't surprising such things would interfere with it working.

There are a couple things that likely can increase the reading between those, but then you get into whether you are processing to get a target rather than getting useful data. That is why if it works I accept it, and if not approach the problem in other ways.

Just as an example, I took track 8, and EQ'd a .15 db bubble from 100hz to 1000hz. Instead of a maximum null those two nulled to 35 db left and 36 db right in Diffmaker. So the reason track 8 and the original only null to the same level could be such a minor response difference.

 

[manisandher]

I got 33 and 37 db doing that.

Thanks (Dennis?).

So in absolute terms, these measurements are meaningless. But is there anything to them in relative terms? I.e. do they suggest that #9 is closer than #8 to #1, or is that stretching things a bit too far?

Mani.

 

[RayDunzl]

Here's a simple difference of 1 and 8 in Audacity.

I picked a point for time sync at about 1:36.6

It stays synced for less than a second, showing growing differences before and after due to the tracks having a slightly different timebase before (DAC clock) and after going through the ADC clock.

Total time shown is 17 seconds

 

[Blumlein 88]

Thanks (Dennis?).

So in absolute terms, these measurements are meaningless. But is there anything to them in relative terms? I.e. do they suggest that #9 is closer than #8 to #1, or is that stretching things a bit too far?

Mani.

Yes it is Dennis.

No not meaningless. 8 and 9 share about as close to identical FR as possible or the null couldn't have reached below 90 db. They apparently have as close to perfect similarity as possible. Once in the analog world there is thermal noise. These files likely are so similar any differences are below thermal noise. Meaning if you listen to it one time and listen a minute later the thermal noise is different, but the file playback differences are below that if there are any. Nothing different to hear.

The issue with comparing to the original file is timing and FR. The null test is so sensitive extremely minor FR differences reduce the null. We already know your DAC/ADC loop droops a bit below 10 hz. Even that can alter the results. It is quite possible they also droop some tiny fraction at the upper end near 20 khz.

Next is timing. Ray's post above is showing that. The clocks of both recordings run very slightly fast. However, your sampling is delayed by about 3 nanoseconds for every meter of cable bewteen DAC and ADC. So comparing the original to a recording it probably starts out behind, eventually catches up and is in phase with the original. The difference will be a minimum at that point. Then slowly the recording gets ahead of the original file and the difference grows larger. With a long enough file you can see that repeat over a regular sequence. Another tell tale to that condition is comparing FFT of the difference file. If it has a 6 db per octave upward tilt vs the original it probably is a mis-timing issue. Higher frequencies are more effected than lower frequencies.

Now Diffmaker can, and sometimes is successful at fixing the timing between files not just at one point, but throughout the file. It also will match gain very precisely, but here is where an FR difference can corrupt that process. So when it works it fixes shifts in time, drifts in clocking and level differences to get the deepest possible null. However this is a complex process and sometimes it gets tripped up.

So the original vs 8 or 9 being in the mid 30 db range probably isn't fully correct. Ray's post above shows at some point it gets to a fairly deep null. It probably is much more than 30 db, but whether it is 90 db nulls or not we couldn't say. Also even a .1 db FR issue raises the null, but assessing that vs audibility isn't clearcut. It probably isn't audible even though it reduces the real null depth. If a device is causing distortion and that was enough for a 30 db null the result is rather audible. So really deep null numbers tell you not much of anything is different. You get to moderate or low null numbers and what can be deduced depends on what is causing the differences.

 

[RayDunzl]

Ray's post above shows at some point it gets to a fairly deep null. It probably is much more than 30 db, but whether it is 90 db nulls or not we couldn't say.

Zooming in on the point I used to synchronize timing, showing the sample values for 1 and 8, with a short segment of the diff file amplified... The display covers about 8 milliseconds.

The amplification of the difference segment is 31.15 dB... visual amplification is 36.13 times, the "energy" amplification is 1305.56 times.

Doing the same between 8 and 9 permits an amplification of 29.754 dB, and looks about the same.

 

[fas42]

Thanks for all your help guys.

FWIW, I hear a difference between files #8 and #9 too. I'd describe the difference in exactly the same way that I described the difference I initially heard between #2 and #3 (before I started doubting myself). Incidentally, file #8 was with the microRendu and file #9 with the Phasure Mach II - everything else in the chain remained exactly the same.

Thanks for that confirmation, Mani. From my point of view you're right on the money; in the areas that I take seriously when listening for qualities in the sound, the difference is very stark. Amir states that it is like bottles of water - okay, consider ones made in different processing plants and assembled into a pack. Water is water, right?? ... Wrong, for those sensitive to various trace compounds and other factors, yes, the water will taste different ... and being sensitive to those variations is something that a person can be 'trained' to achieve.

I'll mention an aspect of how I listen to replay - I don't listen to bass, midrange, treble; I listen as if I'm listening to a live performance, I expect the system to deliver the emotional punch of the real thing - if it doesn't it's got problems, if it delivers some of the impact of live music playing then it's well ahead. This is the criterion I used with those versions, 8 and 9.

 

[fas42]

Let me manufacture a difference:

A and B are sonically identical. They also measure identically via FFT. They just don't look the same.

DIFF AB is the simple sample by sample difference. The difference is not part of either A or B. It is also sonically different, and measures somewhat differently via FFT.

View attachment 3834

A and B are not sonically identical - for something that is sensitive to phase they are cheese and chalk. The time domain is where the action is, not the frequency domain. But you have brought up a key point - it is incredibly hard to perfectly synchronise two waveforms to truly extract what the difference is at a certain point - quite a bit harder than what you and Dennis are suggesting. I've managed to fool myself a couple of times by having less than 100% synch, thought I had something real, but it evaporated when I had a rethink.

DiffMaker lives in a dream world, with the numbers it comes up with - Dennis has remarkable faith in it, I must say .

 

[Thomas savage]

A and B are not sonically identical - for something that is sensitive to phase they are cheese and chalk. The time domain is where the action is, not the frequency domain. But you have brought up a key point - it is incredibly hard to perfectly synchronise two waveforms to truly extract what the difference is at a certain point - quite a bit harder than what you and Dennis are suggesting. I've managed to fool myself a couple of times by having less than 100% synch, thought I had something real, but it evaporated when I had a rethink.

DiffMaker lives in a dream world, with the numbers it comes up with - Dennis has remarkable faith in it, I must say .

Maybe we should try WishMaker ..

 

[Purité Audio]

It was just my imagination ... running away with me
Keith

 

[RayDunzl]

It was just my imagination ... running away with me

What a temptation..