Audiosciencereview.com/. legit?

Irvrobinson

Irvrobinson

Audioholic Spartan
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.
I have no idea if he contacted Marantz, but from reading the now 19 page thread, it doesn't appear to be the case. We could always ask him.
 
P

PENG

Audioholic Overlord
I hope Marantz answers, being a new owner of a different Marantz product, but I won't hold my breath.
Agreed, I just have to try. In theory those spikes of THD+N shown in the FFT shouldn't be audible to humans but as I really want to know if the root cause is simply as Amir surmised, incorrect filter setting that should be corrected via FW update. If we only consider the 20-22,000 Hz band, the numbers still look very decent.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
Agreed, I just have to try. In theory those spikes of THD+N shown in the FFT shouldn't be audible to humans but as I really want to know if the root cause is simply as Amir surmised, incorrect filter setting that should be corrected via FW update. If we only consider the 20-22,000 Hz band, the numbers still look very decent.
One thing I've noticed about the Marantz AVR I purchased less than two months ago, is that it has had two firmware updates installed that I'm aware of. (I have auto update turned on.). Marantz doesn't tell you what's in the updates, and I've suspected it has more to do with the streaming services the AVR supports than anything else, but if the digital filter is programmable, I wonder if what Amir measured wasn't a design bug, but the result of a bug in a firmware update. If Marantz did a faulty firmware change, and didn't bother to do a full set of measurements like Amir did, the bug may have gone unnoticed, and even propagated between firmware generations.
 
P

PENG

Audioholic Overlord
One thing I've noticed about the Marantz AVR I purchased less than two months ago, is that it has had two firmware updates installed that I'm aware of. (I have auto update turned on.). Marantz doesn't tell you what's in the updates, and I've suspected it has more to do with the streaming services the AVR supports than anything else, but if the digital filter is programmable, I wonder if what Amir measured wasn't a design bug, but the result of a bug in a firmware update. If Marantz did a faulty firmware change, and didn't bother to do a full set of measurements like Amir did, the bug may have gone unnoticed, and even propagated between firmware generations.
The 2018 models have a total of 4 updates so far except the SR5013 that has only 3. Technically only 3, or 2 for the SR5013, because the last one (the 4th) was done to correct a bug brought on by 3rd update.

https://www.avsforum.com/forum/90-receivers-amps-processors/2975122-official-2018-marantz-nr-series-sr-series-avr-owner-s-thread-faq-posts-1-7-a.html

See post#5

3. 4-17-2019
- Improves overall performance and stability
4. 4-23-2019
- Resolves control system issue caused by 4-17-2019 update

I think FW updates typically have to do with features only, that's why I felt it is important to let Marantz know about the kind of issues Amir discovered. If this cannot be corrected by FW then as long as they know about, there is a chance they will address such issues in their 2020 models, assuming it is too late for the 2019 models by now.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
Going back to the audiosciencereview.com website, Amir just posted a review of a QSC amp, another sample received from a member rather than a manufacturer sample, and it shows some unexpected inter-channel performance differences. I think it's interesting to see the reviews of "the real thing", rather than what I assume are "checked out and tested" manufacturer samples. It makes me wonder. The SINAD chart for amplifiers is also interesting, in that the Class D Hypex NC400 (which I've been skeptical of) is second from the top. Fascinating.
 
Verdinut

Verdinut

Audioholic Samurai
Going back to the audiosciencereview.com website, Amir just posted a review of a QSC amp, another sample received from a member rather than a manufacturer sample, and it shows some unexpected inter-channel performance differences. I think it's interesting to see the reviews of "the real thing", rather than what I assume are "checked out and tested" manufacturer samples. It makes me wonder. The SINAD chart for amplifiers is also interesting, in that the Class D Hypex NC400 (which I've been skeptical of) is second from the top. Fascinating.
I think it's kind of stupid reporting results on the QSC amplifier with important differences in the performance of the channels. IMO, the tested unit is obviously defective and the results would not represent the performance of an identical flawlessly performing product model.

A serious reviewer, seeing important disparate performance from a serious manufacturer's published specs, should at least test a second sample before making judgment on a product and possibly publishing untruthful info to prospective buyers.
 
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lovinthehd

lovinthehd

Audioholic Slumlord
I think it's kind of stupid reporting results on the QSC amplifier with important differences in the performance of the channels. IMO, the tested unit is obviously defective and the results would not represent the performance of an identical flawlessly performing product model.

A serious reviewer, seeing important disparate performance from a serious manufacturer's published specs, should at least test a second sample before making judgment on a product and possibly reporting untruthful info to prospective buyers.
While Amir may be a better reviewer in some respects than the shills that write for various audio mags/blogs, he's still pretty opinionated. If he were a serious reviewer he could do as suggested or even have someone double check his setup (IIRC he's not always done so well with that, altho he may be again better than most mag/blog reviewers in this respect but that's not saying a lot most of the time).
I think it's kind of stupid reporting results on the QSC amplifier with important differences in the performance of the channels. IMO, the tested unit is obviously defective and the results would not represent the performance of an identical flawlessly performing product model.

A serious reviewer, seeing important disparate performance from a serious manufacturer's published specs, should at least test a second sample before making judgment on a product and possibly publishing untruthful info to prospective buyers.
Even hand picked units from manufacturers can possibly not represent a typical production model....never been too impressed with Amir myself, his ego and hi-end infatuation color things too much IMO.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
I think it's kind of stupid reporting results on the QSC amplifier with important differences in the performance of the channels. IMO, the tested unit is obviously defective and the results would not represent the performance of an identical flawlessly performing product model.

A serious reviewer, seeing important disparate performance from a serious manufacturer's published specs, should at least test a second sample before making judgment on a product and possibly publishing untruthful info to prospective buyers.
A second sample? Amir usually tests products sent to him by consumers who purchased them, not manufacturers. This is one reason why I think his testing is so interesting. So far, Amir is the most serious product tester I've seen in consumer electronics. Even the better channel of the QSC DCA2422 he tested was mediocre in objective performance, though his main issue with the product was fan noise, which he considered unacceptable for home environments. If the QSC out-performed otherwise I'd have to hear the fan noise for myself, but as classical music fan I've already sold one pair of fan-cooled amps in the past (Krell KMA-100 II) because the fan noise annoyed me, so I'd be skeptical. As it happens the QSC looks like a maximum power-optimized implementation that measures no better than most cheap AVRs, if not worse.

In the case of the Benchmark Media DAC3, for example, Amir found that a sample sent to him did not measure as expected. Benchmark's VP of Engineering joined the thread, claimed the sample was defective, and sent Amir a factory sample. Lo and behold the measurements of the factory sample were superior. Supposedly the product owner's unit was sent back to Benchmark, but the outcome never appeared in the thread. I'm curious because I use a DAC3, and I'm wondering about Benchmark's true field performance.
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
While Amir may be a better reviewer in some respects than the shills that write for various audio mags/blogs, he's still pretty opinionated. If he were a serious reviewer he could do as suggested or even have someone double check his setup (IIRC he's not always done so well with that, altho he may be again better than most mag/blog reviewers in this respect but that's not saying a lot most of the time).

Even hand picked units from manufacturers can possibly not represent a typical production model....never been too impressed with Amir myself, his ego and hi-end infatuation color things too much IMO.
Amir has a high-end infatuation but measures $99 DACs? Do you see anyone else measuring low-cost equipment?

I find it fascinating that Amir runs a wide array of measurements, posts the results for anyone to see, takes no advertising, and then gets criticized by people who do nothing but post opinions. I admire the guy because he makes tangible contributions to increasing the objective information available in the field. Who does better? Personally, I take most of the commentary from any site, including this one, as just opinion, and I don't take it all that seriously. The measurements, on the other hand, are invaluable.
 
S

Speedskater

Senior Audioholic
Amir dosn't have the horsepower that Stereophile & TAS have. He can't push manufactures around. He's doing the tests on his own time and out of his own pocket (with sample units from friends). He doen't have a staff of employees to keep track of loose ends.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Even the better channel of the QSC DCA2422 he tested was mediocre in objective performance...
I'm trying to get more acquainted with Amir's measurements.

This is about right?

At 5 Watts, 22.5kHz BW:

SNR: 90dB (Ch1 and Ch2)
THD: 0.05% (Ch1), 0.006% (Ch2)
FR: 20Hz-20kHz +0dB/ -0.4dB
Crosstalk: ?

Is the SNR A-weighted (dBA) ?
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
One thing Amir wrote about Room Response and Auto Room EQ that agrees with some of us:

"I have used REW's automatic parametric EQ system. It generated a much more ideal curve than I could do manually. Yet, it sounded worse than my manual system. So again, you can't go by how good of a curve you get. You must use your ears."

"The issue is that you MUST listen to results of room equalization and only then declare what works and what doesn't. Throwing graphs at me as proof of one system being better is wrong. The graphs are produced with one microphone. Not two ears. And a brain."


I like the guy already. :D
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
I'm trying to get more acquainted with Amir's measurements.

This is about right?

At 5 Watts, 22.5kHz BW:

SNR: 90dB (Ch1 and Ch2)
THD: 0.05% (Ch1), 0.006% (Ch2)
FR: 20Hz-20kHz +0dB/ -0.4dB
Crosstalk: ?

Is the SNR A-weighted (dBA) ?
The SNR is unweighted, but bandwidth limited, as he does for all amps with a switching power supply.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
One thing Amir wrote about Room Response and Auto Room EQ that agrees with some of us:

"I have used REW's automatic parametric EQ system. It generated a much more ideal curve than I could do manually. Yet, it sounded worse than my manual system. So again, you can't go by how good of a curve you get. You must use your ears."

"The issue is that you MUST listen to results of room equalization and only then declare what works and what doesn't. Throwing graphs at me as proof of one system being better is wrong. The graphs are produced with one microphone. Not two ears. And a brain."


I like the guy already. :D
And this is where Amir and I diverge, and while I read his commentary I don't necessarily agree with it. IMO, the only way to know if a system is accurate is to measure at the listening seat and verify & adjust with recordings made in the same room. You can also use recordings made in other rooms, but you have to be very familiar with the sound of the instruments or the things you used to make the recordings. For example, if you don't have access to numerous instruments like I do, rapping on an upside down 5 gallon plastic bucket with a stick or even various tools can be very revealing when the recording is played back. Admittedly though, my only "tuning tools" for frequencies above 200Hz is speaker and listening seat placement, but below that I use parametric EQ in addition to placement.
 
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P

PENG

Audioholic Overlord
And this is where Amir and I diverge, and while I read his commentary I don't necessarily agree with it. IMO, the only way to know if a system is accurate is to measure at the listening seat and verify & adjust with recordings made in the same room. You can also use recordings made in other rooms, but you have to be very familiar with the sound of the instruments or the things you used to made the recordings. For example, if you don't have access to numerous instruments like I do, rapping on an upside down 5 gallon plastic bucket with a stick or even various tools can be very revealing when the recording is played back. Admittedly though, my only "tuning tools" for frequencies above 200Hz is speaker and listening seat placement, but below that I use parametric EQ in addition to placement.
ADTG is highly variable in a sense, sometime he seems to go 100% objective, i.e. verified specs etc., other time he would just go by ears (his ears only obviously).
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
The SNR is unweighted, but bandwidth limited, as he does for all amps with a switching power supply.
22.5kHz BW means 20Hz-22.5kHz, right?

If he could do 1 watt SNR, that would be more like what we are used to seeing on AH.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
ADTG is highly variable in a sense, sometime he seems to go 100% objective, i.e. verified specs etc., other time he would just go by ears (his ears only obviously).
Yeah, I'm pretty easy going that way. :D

I believe the salient point is what most people believe - any good graph or measurement can be good guide, but it has to be accompanied by good sound.

If you can get a good graph (or measurement) plus good sound, then you would keep that setup.

But if you get a good graph plus bad sound, then you wouldn't keep the setup no matter how great the graph looks.
 

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