Audiosciencereview.com/. legit?

[Phase 2]

So I ran across this website, they test a lot of DAC, but what caught my eye was a test on Marantz's Flagship processer. From some of his test results it didn't test out very well. So is this site a good source of information? It also has a Forum like AH. Your thoughts?

 

[BoredSysAdmin]

I believe it is legit. Any attempts to measure and not blindly trust subjective experiences are welcome in my book.
As to the accuracy or methodology of their measuring methods - I can't say anything useful.

 

[lovinthehd]

Amir can afford good test gear....

 

[PENG]

If you believe him, he said the following in the conclusions

From subjective point of view, if you wrestle enough with Audyssey Room EQ, you should be able to get better in-room performance than any non-EQ DAC in a real room. Then again, you can get the same in much cheaper AVRs and processors.

I would say buy the Marantz AV8805 because it has the features it has not because you think it will provide reference quality audio performance. It will not.

I do, the highlighted part anyway.., and I am done with prepros altogether let alone flag ship AVPs, at least for the next year or 2.

I read that review a few time already and have done some search since, and I am still wondering why he would measure SINAD in dB, that appears to be typically used to measure communication equipment, not audio. Edit: I took another look and realized it was just THD+N expressed in dB.

It is also worth noting, at least to a point that, his numbers are for the XLR output of > 4V, that is > 2 V unbalanced. Also, I don't think he is comparing apple to apple when he compared the results to that of desktop DACs. The pre out of the AV8805 bound to have more THD and noise post DAC, due to the preamp stage (even with the recent upgrade that was mentioned in the review of the AVR-X8500H),and being a Marantz, it also has the HDAM buffer stage, i.e. more discrete parts.

 

[highfigh]

If you believe him, he said the following in the conclusions



I do, the highlighted part anyway.., and I am done with prepros altogether let alone flag ship AVPs, at least for the next year or 2.

I read that review a few time already and have done some search since, and I am still wondering why he would measure SINAD, that appears to be typically used to measure communication equipment, not audio. May be @gene , our residential EE specialized in communications can comment on that. I don't doubt that is is a valid measurement criteria, but I am not sure if it matter much to audio gear where we typically are concerned only with SNR/DNR and THD+N, not SINAD that is signal over noise and distortions.

It is also worth noting, at least to a point that, his numbers are for the XLR output of > 4V, that is > 2 V unbalanced. Also, I don't think he is comparing apple to apple when he compared the results to that of desktop DACs. The pre out of the AV8805 bound to have more THD and noise post DAC, due to the preamp stage (even with the recent upgrade that was mentioned in the review of the AVR-X8500H),and being a Marantz, it also has the extra HDAM buffer stage.

According to the Marantz site, HDAM isn't for buffering, it's to replace IC op-amps with discrete components. If one company uses something like the TI TL072, they might have complaints about the noise level and lack of headroom but they could just as easily have done better by using the TL073. If Marantz accomplishes the same function with a discrete assembly and, I would assume, they listened to it to compare, maybe it IS better, but it would be hard to verify in the wild. However, it's not necessarily a buffer.

HDAM SA
Marantz developed its own discrete circuit boards to replace standard IC's. These HDAM's consists of discrete surface mount components with short mirror image L/R signal paths. Those devices are doing exactly the same thing as the Op-Amps, but outperform the regular IC Op-amps dramatically in terms of the Slew Rate and reduced noise level, resulting in a much more dynamic, accurate and detailed sound. Over the years Marantz developed different types of the HDAM to improve quality and to fit to the special requirements of a product category like CD or amplifier.

 

[PENG]

According to the Marantz site, HDAM isn't for buffering, it's to replace IC op-amps with discrete components. If one company uses something like the TI TL072, they might have complaints about the noise level and lack of headroom but they could just as easily have done better by using the TL073. If Marantz accomplishes the same function with a discrete assembly and, I would assume, they listened to it to compare, maybe it IS better, but it would be hard to verify in the wild. However, it's not necessarily a buffer.

HDAM SA
Marantz developed its own discrete circuit boards to replace standard IC's. These HDAM's consists of discrete surface mount components with short mirror image L/R signal paths. Those devices are doing exactly the same thing as the Op-Amps, but outperform the regular IC Op-amps dramatically in terms of the Slew Rate and reduced noise level, resulting in a much more dynamic, accurate and detailed sound. Over the years Marantz developed different types of the HDAM to improve quality and to fit to the special requirements of a product category like CD or amplifier.

The current version found in their AVPs and AVRs (since the AVR7010/AV8802) is sort of a buffer stage, with unity gain. I read the schematics myself, after reading Dr. Rich's article.

Below is how Marantz described the older version, when it did amplify as well as buffering:

https://www.us.marantz.com/blog/pages/posts.aspx?pid=11

"The discrete surface mount components are placed in a single module with short, mirrored circuit paths to amplify and buffer line-level signals. This results in lower noise and an improved slew rate for richer, more dynamic sound that accurately reproduces slight high-frequency details."

What you quoted from Marantz and the "buffer" stage are not mutually exclusive so they can be, and in fact are both. I shouldn't have used the word "extra" though, that creates confusion. Edited out now, and thanks..

 

[highfigh]

The current version found in their AVPs and AVRs (since the AVR7010/AV8802) is sort of a buffer stage, with unity gain. I read the schematics myself, after reading Dr. Rich's article.

Below is how Marantz described the older version, when it did amplify as well as buffering:

https://www.us.marantz.com/blog/pages/posts.aspx?pid=11

"The discrete surface mount components are placed in a single module with short, mirrored circuit paths to amplify and buffer line-level signals. This results in lower noise and an improved slew rate for richer, more dynamic sound that accurately reproduces slight high-frequency details."

What you quoted from Marantz and the "buffer" stage are not mutually exclusive so they can be, and in fact are both. I shouldn't have used the word "extra" though, that creates confusion. Edited out now, and thanks..

Honestly, I would hope the inputs are buffered.

I have been to several Denon/Marantz training sessions, but the places weren't very conducive to critical listening. I will say the two brands did sound different, but I don't know how they were set up- we weren't allowed to play with the menu.

 

[PENG]

From the schematics, barring any hidden info, the HDAM actually does look like "extra", but I edited it out from my out from my original post regardless just in case there are things in fact not shown in the Denon's equivalent diagrams, though obviously the possibilities exist. Other than that stage, the corresponding schematics (between the D and the M) "look" identical.

 

[PENG]

Honestly, I would hope the inputs are buffered.

I have been to several Denon/Marantz training sessions, but the places weren't very conducive to critical listening. I will say the two brands did sound different, but I don't know how they were set up- we weren't allowed to play with the menu.

I took the time to compare the schematics meticulously to the point I needed eye drops lol.. You can view them at hifiengine.com, or elsewhere if you search hard. I also listened very carefully, and use REW to plot comparable graphs, and I have no doubt they don't sound different by themselves, but suppose you may have to do it blind to convince yourself.. HDAM is supposed to do the things Marantz claimed, but like anything else there are always pros and cons when you get further away from simplicity by adding parts and circuitry, just hopefully much more pros. And if it does work as well as claimed, they would still be limited by the parts and circuitry upstream that are the real bottlenecks as Dr. Rich pointed out all the way back in 201/2013?.

To me, like Denon's AL32 on the digital side, those things are mostly marketing hype that serves to active and enhance the well known Placebo effects, expectation bias etc.. My Cambridge audio preamp has similar buffer stage, they call it Terrapin modules, wonder if you have heard about those.

 

[Irvrobinson]

If you believe him, he said the following in the conclusions

I do, the highlighted part anyway.., and I am done with prepros altogether let alone flag ship AVPs, at least for the next year or 2.

I read that review a few time already and have done some search since, and I am still wondering why he would measure SINAD, that appears to be typically used to measure communication equipment, not audio. May be @gene , our residential EE specialized in communications can comment on that. I don't doubt that is is a valid measurement criteria, but I am not sure if it matter much to audio gear where we typically are concerned only with SNR/DNR and THD+N, not SINAD that is signal over noise and distortions.

It is also worth noting, at least to a point that, his numbers are for the XLR output of > 4V, that is > 2 V unbalanced. Also, I don't think he is comparing apple to apple when he compared the results to that of desktop DACs. The pre out of the AV8805 bound to have more THD and noise post DAC, due to the preamp stage (even with the recent upgrade that was mentioned in the review of the AVR-X8500H),and being a Marantz, it also has the HDAM buffer stage, i.e. more discrete parts.

My take on audiosciencereview is the same as any other product review site, in any category (e.g. Consumer Reports on cars and refrigerators),measurements are always welcome, and subjective interpretation is interesting, but you really need to come to your own conclusions. I think Amir is providing an extremely valuable service to the audio community, and lately I spend more time there than on AH. (I don't post on any audio site but AH.).

Regarding the use of SINAD, Amir is obviously looking for an overall circuit implementation quality figure of merit, and then he uses it to classify products. To be honest, I find his classification intellectually interesting, but having compared the sound of my old Benchmark Media DAC1-HDR with my new and latest DAC3L, I couldn't hear any differences at all, switching back and forth on the same material, even though they are presented as far apart in his chart. In reality, the differences between the two SINAD measurements are small enough to be irrelevant, and I ignore them. The DAC3's advantage is in usability, not audio performance. If not for the DAC3's remote-operated volume control being so superior to the DAC1's in actual use, I would have never upgraded. (And the fact that the DAC3 has far better power management.)

I think the other inconvenient reality is that with any technical data, and Amir's measurements are certainly in that category, you have to have enough knowledge in the field to understand what the measurements mean and place them in context. Sometimes I wish we'd stop referring to ratios in db and percentages of reference levels and get back to microvolts, because IMO simpler data is easier for humans to interpret.

Again, I'm a huge fan of what Amir is trying to do, and I admire his reviews, even if I don't always completely agree with his reasoning or his conclusions.

 

[PENG]

My take on audiosciencereview is the same as any other product review site, in any category (e.g. Consumer Reports on cars and refrigerators),measurements are always welcome, and subjective interpretation is interesting, but you really need to come to your own conclusions. I think Amir is providing an extremely valuable service to the audio community, and lately I spend more time there than on AH. (I don't post on any audio site but AH.).

Regarding the use of SINAD, Amir is obviously looking for an overall circuit implementation quality figure of merit, and then he uses it to classify products. To be honest, I find his classification intellectually interesting, but having compared the sound of my old Benchmark Media DAC1-HDR with my new and latest DAC3L, I couldn't hear any differences at all, switching back and forth on the same material, even though they are presented as far apart in his chart. In reality, the differences between the two SINAD measurements are small enough to be irrelevant, and I ignore them. The DAC3's advantage is in usability, not audio performance. If not for the DAC3's remote-operated volume control being so superior to the DAC1's in actual use, I would have never upgraded. (And the fact that the DAC3 has far better power management.)

I think the other inconvenient reality is that with any technical data, and Amir's measurements are certainly in that category, you have to have enough knowledge in the field to understand what the measurements mean and place them in context. Sometimes I wish we'd stop referring to ratios in db and percentages of reference levels and get back to microvolts, because IMO simpler data is easier for humans to interpret.

Again, I'm a huge fan of what Amir is trying to do, and I admire his reviews, even if I don't always completely agree with his reasoning or his conclusions.

I think you and I are on similar wavelength.

By the way, I just realized the SINAD thing is just THD+N in dB instead of %, it really is the same, the conversion formula for converting dB to % is 10^(dB value/20), i.e. the antilog of the value in dB/20, I even have my own spreadsheet for such conversion. Apparently in communication they called it SINAD and measured in dB whereas audio preamps/amps are typically measured in %, at least those by Audioholics, Stereophile, S&V and others.

 

[AcuDefTechGuy]

...usability, not audio performance.

Other than functionality or usability, expensive DAC is a total waste of money, but some people have big ears.

Unless you just like the aesthetics or coolness factor.

 

[Irvrobinson]

Other than functionality or usability, expensive DAC is a total waste of money, but some people have big ears.

Unless you just like the aesthetics or coolness factor.

Well, remember, in my audio-only system I'm using the DAC3-L primarily as a pre-amp and the DAC functionality, while I want it to be as good as possible, is a secondary consideration. I don't like Benchmark's half-width form factor, I'm not especially thrilled with their pricing, their remote control is a tiny bit funky (though it is made of aluminum and not cheap plastic), but their build quality is top-notch and the balanced outputs have a very low impedance, so they can handle a complex load with two stages of splitters, and their products never make a thump or any other wayward noise on switching or power-down / power-up. Oftentimes, excellent design and build quality has a higher price associated with it.

 

[mtrycrafts]

..., but I don't know how they were set up- we weren't allowed to play with the menu.

A critical issue.

 

[Matthew J Poes]

My take on audiosciencereview is the same as any other product review site, in any category (e.g. Consumer Reports on cars and refrigerators),measurements are always welcome, and subjective interpretation is interesting, but you really need to come to your own conclusions. I think Amir is providing an extremely valuable service to the audio community, and lately I spend more time there than on AH. (I don't post on any audio site but AH.).

Regarding the use of SINAD, Amir is obviously looking for an overall circuit implementation quality figure of merit, and then he uses it to classify products. To be honest, I find his classification intellectually interesting, but having compared the sound of my old Benchmark Media DAC1-HDR with my new and latest DAC3L, I couldn't hear any differences at all, switching back and forth on the same material, even though they are presented as far apart in his chart. In reality, the differences between the two SINAD measurements are small enough to be irrelevant, and I ignore them. The DAC3's advantage is in usability, not audio performance. If not for the DAC3's remote-operated volume control being so superior to the DAC1's in actual use, I would have never upgraded. (And the fact that the DAC3 has far better power management.)

I think the other inconvenient reality is that with any technical data, and Amir's measurements are certainly in that category, you have to have enough knowledge in the field to understand what the measurements mean and place them in context. Sometimes I wish we'd stop referring to ratios in db and percentages of reference levels and get back to microvolts, because IMO simpler data is easier for humans to interpret.

Again, I'm a huge fan of what Amir is trying to do, and I admire his reviews, even if I don't always completely agree with his reasoning or his conclusions.

Not that we have a better metric, but SINAD has never been well correlated with perceptions of good sound. IT was used for that and studied for a while but the fidelity requirements were so low that the measure isn't suited to higher fidelity situations like sound reproduction. SINAD, or Signal to Noise and Distortion has been investigated and correlated with blind tests of perception of sound and distortion, the correlation is really low. One of the better more recent studies was Geddes own distortion study where he developed a better metric and tried to get the industry to adopt it. It's a good read because he also points out some of the past research showing how poor a predictor THD is of sound quality. The problem is that you can have really high levels of benign distortion that isn't perceivable or noticeable as bad. You can have really low levels of high order harmonic distortion that is noticeable but contributes to very low THD levels. The fidelity of modern electronics has gotten so good at this point that things like high order harmonics are now the most audible non-linear detriments left. Some research, like Geddes own, show that these distortions are quite audible and quite detrimental, so I don't know that they should be totally written off, but we've made zero progress in replacing bad measures with better ones. SINAD is a bad proxy for sound quality.

 

[Matthew J Poes]

Marantz sticks opamps on either side of the HDAM which, while not totally dumb, does seem a little silly. I don't have a problem with good opamps, there are lots of very clean and cheap opamps with very low noise and distortion, so I don't see a reason to use discrete necessarily. Maybe if you need to run very high rails or push a lot of current, like SPL does, but otherwise opamps are fine.

I'm not totally sure of this, but the Marantz may not be a true dual-differential design. I thought the 8000 series was, but the 7000 series and their amplifiers are not and use a balanced convert chip. They don't use the very good THAT chips and as such their balanced outs are noisier and have higher distortion than the single-ended outputs. A practice that, in my opinion, is really dumb.

 

[Irvrobinson]

I think you and I are on similar wavelength.

By the way, I just realized the SINAD thing is just THD+N in dB instead of %, it really is the same, the conversion formula for converting dB to % is 10^(dB value/20),i.e. the antilog of the value in dB/20, I even have my own spreadsheet for such conversion. Apparently in communication they called it SINAD and measured in dB whereas audio preamps/amps are typically measured in %, at least those by Audioholics, Stereophile, S&V and others.

Like I said, from reading Amir's site I think he's just looking for a figure of merit, and it is difficult to argue that a higher SINAD ratio doesn't somehow reflect implementation quality. I hear Matthew about lack of correlation to audibility, but when you're talking about anything more than 80db below a fundamental level it's probably not correlated to audibility, no matter what you're measuring.

Personally, I'm not one to pay attention to figures of merit on just about any device. Computers, cars, audio equipment, whatever. Figures of Merit work for resistors, but I want more than one measure even for a capacitor. ;-). Like I said, his chart is intellectually interesting, but I didn't make a buying decision based on it.

 

[PENG]

Like I said, from reading Amir's site I think he's just looking for a figure of merit, and it is difficult to argue that a higher SINAD ratio doesn't somehow reflect implementation quality. I hear Matthew about lack of correlation to audibility, but when you're talking about anything more than 80db below a fundamental level it's probably not correlated to audibility, no matter what you're measuring.

Personally, I'm not one to pay attention to figures of merit on just about any device. Computers, cars, audio equipment, whatever. Figures of Merit work for resistors, but I want more than one measure even for a capacitor. ;-). Like I said, his chart is intellectually interesting, but I didn't make a buying decision based on it.

I do think he was being too harsh on the Marantz's numbers relative to the DAC that he said cost less than the Marantz's shipping cost. Good humor in a way but misleading because it wasn't a fair comparison. There aren't too many preamps or power amps that has THD+N better than many mid range external DACs. That Benchmark power amp is among the few exceptions.

 

[Irvrobinson]

I do think he was being too harsh on the Marantz's numbers relative to the DAC that he said cost less than the Marantz's shipping cost. Good humor in a way but misleading because it wasn't a fair comparison. There aren't too many preamps or power amps that has THD+N better than many mid range external DACs. That Benchmark power amp is among the few exceptions.

Okay, I finally read that review. The only thing he found that was concerning at all, which was also the root cause of his poor SINAD measurement, was that very odd digital filtering implementation. Amir, being a former product developer himself, was probably appalled that a design flaw like that could escape unnoticed, so he let a little emotion get into the review. It does make you wonder...

Amir also tests samples he gets from customers (and the Marantz was one of those cases),and sometimes anomalies are found. For example, when Amir tested the Benchmark Media DAC3, he found some noise sidebands on the conversion of a 12KHz test signal:

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-dac3.3545/

It's a huge thread, 24 pages long, and finally in post #204, John Siau, Benchmark's VP of Engineering, gets on and helps Amir debug the problem, which turned out to be a suspected fault with the particular unit under test. It's a fascinating thread. What I enjoyed about it was that the investigation process was completely out in the open with no edits. I've got to applaud Amir and Benchmark for that openness.

The Marantz problem appears to be a basic design issue, but Amir speculates it could be fixed in firmware. (I'm not so sure.) I wonder if Marantz will take this on, or not care because the audience is a very limited number of micro-gearheads? ;-)

Regardless of the outcome, I'm still impressed by what Amir is doing.

 

[PENG]

Okay, I finally read that review. The only thing he found that was concerning at all, which was also the root cause of his poor SINAD measurement, was that very odd digital filtering implementation. Amir, being a former product developer himself, was probably appalled that a design flaw like that could escape unnoticed, so he let a little emotion get into the review. It does make you wonder...

He said: "This is flat out broken. I get wanting slow roll off but this smells like incorrectly programmed filter setting. "

So I guess he meant what he said, i.e. incorrectly programmed filter setting. If true, and I tend to think so, then it probably was just an human error that was not by design. Regardless, that off the chart distortions passed 5 kHz really need to be fixed by Marantz, whether it is audible or not for normal music/movie applications.

Amir also tests samples he gets from customers (and the Marantz was one of those cases),and sometimes anomalies are found. For example, when Amir tested the Benchmark Media DAC3, he found some noise sidebands on the conversion of a 12KHz test signal:

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-dac3.3545/

It's a huge thread, 24 pages long, and finally in post #204, John Siau, Benchmark's VP of Engineering, gets on and helps Amir debug the problem, which turned out to be a suspected fault with the particular unit under test. It's a fascinating thread. What I enjoyed about it was that the investigation process was completely out in the open with no edits. I've got to applaud Amir and Benchmark for that openness.

The Marantz problem appears to be a basic design issue, but Amir speculates it could be fixed in firmware. (I'm not so sure.) I wonder if Marantz will take this on, or not care because the audience is a very limited number of micro-gearheads? ;-)

Regardless of the outcome, I'm still impressed by what Amir is doing.

Do you think Amir would have reported his findings to Marantz? I hope he did, and I wouldn't mind that thread runs 24 page long, as long as it gets resolved eventually, otherwise I will feel really sad for those who paid a fortune for this very nice looking and well built, well spec'ed AVP. I also hope it's cousin (though an integrated version) that has essentially the same hardware less the XLR boards and different power supplies, won't have the same issues as the "programming" would have been different for sure.