The AVP (D+M anyway..) that has the lowest THD+N measured so far seems to be a Denon AVR!!

lovinthehd

lovinthehd

Seriously, I have no life.
What did he say about THD? Don't worry unless THD is > 1%, which would be a CLIPPING amplifier? :D

Yeah, most of us here on AH have never worried about any of these numbers.

Now we see ASR talk about THD of 0.0007% and saying that THD of 0.003% (SINAD -90dB) isn't SOTA? :D
Don't remember. LOL clipping at 1%. That I think I did see Amir say :)
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I am not following you on this. Are you saying that a SINAD of 90 is SOTA?
I am saying no way in hell anybody is going to hear the difference between THD of 0.09% vs 0.0007%(-103dB), much less 0.003% (-90dB) vs 0.0007%. So yes, THD of 0.003% is SOTA. Unless God said -90dB is not SOTA.
 
lovinthehd

lovinthehd

Seriously, I have no life.
I am saying no way in hell anybody is going to hear the difference between THD of 0.09% vs 0.0007%(-103dB), much less 0.003% (-90dB) vs 0.0007%. So yes, THD of 0.003% is SOTA. Unless God said -90dB is not SOTA.
God likes drumphy, so there's that. SOTA might just mean State of the Audibility? :)
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
As far as what is the acceptable level of THD, it could be a matter of opinion to some extent, but in general the lower the better.
Better what? Sound quality? Reliability?
 
P

PENG

Audioholic Slumlord
Better what? Sound quality? Reliability?
I am referring to the 1 kHz measuring standard. If you simply accept say 0.1% at 1 kHz, then at 10-12 kHz you end be up to 1%. So if it is lower, like 0.005%, then you know chances are good that distortions would be below the threshold of audibility even at the much higher frequencies, and/or at very low output level, remember the importance of the first watt?

For me, I am not even worry about THD at 12 kHz and above because even the 2nd harmonics would be at 24 kHz that I cannot hear, though you and I both know there are no shortage of people who claim they can hear the ill effects of distortions from harmonic frequencies that high.
 
D

DJ7675

Audioholic
I am saying no way in hell anybody is going to hear the difference between THD of 0.09% vs 0.0007%(-103dB), much less 0.003% (-90dB) vs 0.0007%. So yes, THD of 0.003% is SOTA. Unless God said -90dB is not SOTA.
SOTA=State of the Art. -90dB is not State of the Art.-120 would be State of the Art. Audibility is an entirely different topic. Science seems to indicate -115dB guarantees transparency. At some point below that noise and distortion could be audible. My thinking is that is going to depend on a persons listening environment, how loud they listen, what they listen to, and their ability to detect distortion etc. -90dB certainly could be inaudible to many but I don’t think you can say it is inaudible in all circumstances with all people all the time. My over simplistic threshold is -96dB. The electronics are available to practically eliminate the possibility of noise/distortion caused by electronics... so why not at least shoot for something close to a SINAD of 100. I have had both pieces the best measuring and the worst measuring AV product on Amirs SINAD chart... I sent in both the X8500 and the NAD T758 V3. While the audio memory isn’t really very reliable... I can tell you that as I turned up the NAD in my home theater to around -10 or louder it sounded harsh and could not play at that level. I don’t have that issue with the Denon. Just my 2 cents and experience FWIW. YMMV
 
lovinthehd

lovinthehd

Seriously, I have no life.
SOTA is a nice goal but becomes somewhat impractical just to chase small improvements....
 
Verdinut

Verdinut

Audioholic Ninja
He did measure cross talk, most of the time anyway. None of the Denon, or any AVR measured well on that one, understandably. Even the $6,600 NAD preamp/processor managed just -92 dB at 1 kHz and -71 dB at 20 kHz, vs the X3600H's -85 dB/-68.5 dB, 1/20 kHz. He typically would note something like "not an audible concern.." Put it this way, you can spend more, such as $6,000 on a Ortofon Xpression and you will be lucky to get 25 dB of channel separation at 15 kHz.:D:D
What's the real purpose of finding importance in crosstalk measurements? I just don't get it.

When several instruments or even a singer and an instrument are recorded in the same room, you obviously have acoustical mixing of the two music sources. Crosstalk measurements is IMO just overkill in testing. A $6,000 Ortofon Xpression has about 25 dB channel separation. Does it ruin the audio performance? I'm sure it doesn't.
 
P

PENG

Audioholic Slumlord
If Amir sees a THD of 0.099%, he'll probably say it's CRAP. :D
H would say that if it is 0.008 %!!:D:D Then if asked, he will undoubtedly say "fortunately not that audible" or " not an audible concern..", or something like that..
 
P

PENG

Audioholic Slumlord
What's the real purpose of finding importance in crosstalk measurements? I just don't get it.

When several instruments or even a singer and an instrument are recorded in the same room, you obviously have acoustical mixing of the two music sources. Crosstalk measurements is IMO just overkill in testing. A $6,000 Ortofon Xpression has about 25 dB channel separation. Does it ruin the audio performance? I'm sure it doesn't.
I am okay with 60 dB at 20,000 Hz, or even 25 dB but that's because my hearing is not the best. I was just responding to a question. So yes, if ASR skip that measurement altogether I may even be okay with that, but then why not, I suppose it only takes a minute to do it.
 
P

PENG

Audioholic Slumlord
SOTA=State of the Art. -90dB is not State of the Art.-120 would be State of the Art. Audibility is an entirely different topic. Science seems to indicate -115dB guarantees transparency. At some point below that noise and distortion could be audible. My thinking is that is going to depend on a persons listening environment, how loud they listen, what they listen to, and their ability to detect distortion etc. -90dB certainly could be inaudible to many but I don’t think you can say it is inaudible in all circumstances with all people all the time. My over simplistic threshold is -96dB. The electronics are available to practically eliminate the possibility of noise/distortion caused by electronics... so why not at least shoot for something close to a SINAD of 100. I have had both pieces the best measuring and the worst measuring AV product on Amirs SINAD chart... I sent in both the X8500 and the NAD T758 V3. While the audio memory isn’t really very reliable... I can tell you that as I turned up the NAD in my home theater to around -10 or louder it sounded harsh and could not play at that level. I don’t have that issue with the Denon. Just my 2 cents and experience FWIW. YMMV
Your last point is one of the two main points I tried pointing out to ADTG, except I am more concerned with the THD in the first watt range than at -10, though I also believe that would be less important in rooms with high noise floor. That is, when we read results such as 104 dB SINAD for the 8500, we may be led to focus on that one number, when one has to look at the varying number across the 20-20,000 Hz range and from fractional watt output to rated output level.

Below are two curves I can quickly pick out for comparison of the pre-out performance. I picked these two because you owned/own both so I can feel safer, though might still be attacked by some NAD AVR fans:D Also, I know neither one was affected by the harmonics and noised in the ultra sonic range.


1597316667517.png



1597316720286.png


So one can see that THD+N is not the same from 20 to 20 kHz.

Now look at the similar effects in the THD+N versus output level and you can see that at 123 W output the NAD was actually quite good with almost -75 dB THD, that is 0.0178%, but then at 1 W it already increased to 0.18%, well pass the 0.1% threshold that some experts suggested would be audible. At 0.25 W (my kind of listening level when watching movies at moderately loud level), THD would be at about -50 dB or 0.32%, even ADTG may hear it right? Compared to the Denon, even at the very low level of 0.05 W, THD was still at slightly below 0.03 %. Again, this is at 1 kHz, at 10 kHz you can expect THD to be significantly higher.

I hope ADTG can see my point why when reading S&V's simplistic THD numbers I wanted to see it lower, or the lower the better in general.:)

1597317065501.png


1597317132557.png


For reference, here's the S&V curve, they didn't always show it but iirc most of the time they did, but I am not sure if most readers would take a careful look at the below 1 W range. Even they did, they would have hard time because of the scale they chose.


1597318221640.png


The T758 V3 still make it to S&V's top pick regardless, and the reviewer said the following:

"But even with Dolby Surround switched off in the GUI, the soundfield was fine-grained and colorful, with notably clear, sumptuous, and well-integrated decays, especially with a solo clarinet part in the second movement. There was also a strong spatial sense of the venue, possibly a mixture of the RoomFeel target and information embedded in the recording. "

"Reggatta de Blanc (LP), never sounded more disciplined and satisfying. "

About Dirac, he said:

"But the room correction also excavated several distinctive high-frequency textures from his cymbal work. Andy Summers’ Telecaster was also a feast of spidery tone as he worked his way through tremolo, phase shifter, and other effects. Dirac rocked this album hard yet subtly. "

"I compared the room-corrected stereo mode to analog bypass and tried to listen beyond the obvious sub-on, sub-off distinction. I was well into side two before realizing that the soundstage was getting a little extra focus from Dirac, though again, it was subtle. "

And at the end he said:

"NAD’s Modular Design Construction makes V3 of the T758 a special occasion as one of the small but growing number of surround products with Dirac. Putting aside the aforementioned challenges with learning to use it, it's an empowering tool for the questing audio tweaker who wants the flexibility to experiment with room correction parameters. Coupled here with this fine-sounding receiver, the audible results are beautiful. "
Such subjective review sections are useless to me, but entertaining to read, most of the time anyway.:D
 
slipperybidness

slipperybidness

Audioholic Spartan
0.1% may look fine to most people if that is the worse case scenario, but if it is measured with a 1 kHz signal at rated output, then it could be much higher at 10 kHz and it may also be much higher at between 0.2 to 1 W.
You make a very valid point!

But, to be certain, when we start talking about the guys that literally wrote the books for proper audio electronics design, they are absolutely talking about the worst case scenario and full bandwidth measurements.

In my experience, there are 3 top dogs that have published their work in this field.

1) Douglas Self
2) G Randy Slone
3) Bob Cordell

For what it is worth, when I enrolled in the Solid State class/lab at the local community college, the prof allowed the class to choose one of the final units of study. Being that we are in Austin, TX ("The Live Music Capital of the World"), we chose audio electronics and we used some sections of a book from Bob Cordell as our reference material for the class.

Here are a few links for extended learning:
(wow! looking at the current price for this book on Amazon, I may have hit gold when I bought this book!)



DS's DIY vendor page:
 
P

PENG

Audioholic Slumlord
You make a very valid point!

But, to be certain, when we start talking about the guys that literally wrote the books for proper audio electronics design, they are absolutely talking about the worst case scenario and full bandwidth measurements.

In my experience, there are 3 top dogs that have published their work in this field.

1) Douglas Self
2) G Randy Slone
3) Bob Cordell

For what it is worth, when I enrolled in the Solid State class/lab at the local community college, the prof allowed the class to choose one of the final units of study. Being that we are in Austin, TX ("The Live Music Capital of the World"), we choose audio electronics and we used some sections of a book from Bob Cordell as our reference material for the class.

Here are a few links for extended learning:
(wow! looking at the current price for this book on Amazon, I may have hit gold when I bought this book!)



DS's DIY vendor page:
Agreed, and I did say 0.1% is fine for me too, if it represents the worse case scenario. S&V's (one that ADTG's often referenced to) 0.1% was for 1 kHz, 1 W into 8 ohms.
 
slipperybidness

slipperybidness

Audioholic Spartan
Agreed, and I did say 0.1% is fine for me too, if it represents the worse case scenario. S&V's (one that ADTG's often referenced to) 0.1% was for 1 kHz, 1 W into 8 ohms.
Let's not miss the fact, the equipment to even measure these low levels of noise and levels of distortion is likely $10,000+++

Any lesser measurement equipment and likely you will just be seeing the distortion in the measurement gear itself.

I'm talking about these really low numbers from ASR and the full bandwidth numbers.

The 1 kHz, 1 W into 8 ohms is a quick way to look for obvious flaws, and tends to make performance look better on paper.
 
D

DJ7675

Audioholic
Thanks for your contributions to the ASR tests
Very welcome. I find the bench tests interesting. I have sent in the following:
Denon X8500, Emotiva XMC1, NAD T758 V3, Lyngdorf TDAI 3400, Musical Fidelity MX-VNYL, Revel MX55 speakers. Many still don’t “get” that ASR bench tests, for the most part, are people that want to know how a piece of gear measures, and send it in to find out. Results are always interesting-both good and bad!
 
D

DJ7675

Audioholic
Your last point is one of the two main points I tried pointing out to ADTG, except I am more concerned with the THD in the first watt range than at -10, though I also believe that would be less important in rooms with high noise floor. That is, when we read results such as 104 dB SINAD for the 8500, we may be led to focus on that one number, when one has to look at the varying number across the 20-20,000 Hz range and from fractional watt output to rated output level.

Below are two curves I can quickly pick out for comparison of the pre-out performance. I picked these two because you owned/own both so I can feel safer, though might still be attacked by some NAD AVR fans:D Also, I know neither one was affected by the harmonics and noised in the ultra sonic range.


View attachment 38790


View attachment 38791

So one can see that THD+N is not the same from 20 to 20 kHz.

Now look at the similar effects in the THD+N versus output level and you can see that at 123 W output the NAD was actually quite good with almost -75 dB THD, that is 0.0178%, but then at 1 W it already increased to 0.18%, well pass the 0.1% threshold that some experts suggested would be audible. At 0.25 W (my kind of listening level when watching movies at moderately loud level), THD would be at about -50 dB or 0.32%, even ADTG may hear it right? Compared to the Denon, even at the very low level of 0.05 W, THD was still at slightly below 0.03 %. Again, this is at 1 kHz, at 10 kHz you can expect THD to be significantly higher.

I hope ADTG can see my point why when reading S&V's simplistic THD numbers I wanted to see it lower, or the lower the better in general.:)

View attachment 38792

View attachment 38793

For reference, here's the S&V curve, they didn't always show it but iirc most of the time they did, but I am not sure if most readers would take a careful look at the below 1 W range. Even they did, they would have hard time because of the scale they chose.


View attachment 38794

The T758 V3 still make it to S&V's top pick regardless, and the reviewer said the following:

"But even with Dolby Surround switched off in the GUI, the soundfield was fine-grained and colorful, with notably clear, sumptuous, and well-integrated decays, especially with a solo clarinet part in the second movement. There was also a strong spatial sense of the venue, possibly a mixture of the RoomFeel target and information embedded in the recording. "

"Reggatta de Blanc (LP), never sounded more disciplined and satisfying. "

About Dirac, he said:

"But the room correction also excavated several distinctive high-frequency textures from his cymbal work. Andy Summers’ Telecaster was also a feast of spidery tone as he worked his way through tremolo, phase shifter, and other effects. Dirac rocked this album hard yet subtly. "

"I compared the room-corrected stereo mode to analog bypass and tried to listen beyond the obvious sub-on, sub-off distinction. I was well into side two before realizing that the soundstage was getting a little extra focus from Dirac, though again, it was subtle. "

And at the end he said:

"NAD’s Modular Design Construction makes V3 of the T758 a special occasion as one of the small but growing number of surround products with Dirac. Putting aside the aforementioned challenges with learning to use it, it's an empowering tool for the questing audio tweaker who wants the flexibility to experiment with room correction parameters. Coupled here with this fine-sounding receiver, the audible results are beautiful. "
Such subjective review sections are useless to me, but entertaining to read, most of the time anyway.:D
Thanks for your reply. I compared those 2 as well and noticed the vast difference of the 8500 and T758 and think it is a very important difference. Amir often leaves the T758 on many graphs as a reference (in a bad way). I too really get a kick out of subjective reviews as well on a very poor performing piece of hardware that has Dirac. I’m looking forward to the review of the T778 to see if NAD has made some improvements. Thanks again for your post.
 
P

PENG

Audioholic Slumlord
Thanks for your reply. I compared those 2 as well and noticed the vast difference of the 8500 and T758 and think it is a very important difference. Amir often leaves the T758 on many graphs as a reference (in a bad way). I too really get a kick out of subjective reviews as well on a very poor performing piece of hardware that has Dirac. I’m looking forward to the review of the T778 to see if NAD has made some improvements. Thanks again for your post.
And I forgot to thank you again, actually can't thank you enough, for sending in your 52 lbs, probably 65 lbs packed flagship unit to ASR. That's major contribution not only to ASR members but potentially would benefit hundreds of people on other forums and also D+M. At least now they know people are watching their flagship's bench test performance too and hopefully would improve on their power amp section for lower THD+N. Not that such a potential improvement in SINAD would be audible, but it might improve sales as potential flagship buyers may be big on such things.:D Wow, just realized you sent in the Lyngdorf too, very generous of you!!
 
D

DJ7675

Audioholic
And I forgot to thank you again, actually can't thank you enough, for sending in your 52 lbs, probably 65 lbs packed flagship unit to ASR. That's major contribution not only to ASR members but potentially would benefit hundreds of people on other forums and also D+M. At least now they know people are watching their flagship's bench test performance too and hopefully would improve on their power amp section for lower THD+N. Not that such a potential improvement in SINAD would be audible, but it might improve sales as potential flagship buyers may be big on such things.:D Wow, just realized you sent in the Lyngdorf too, very generous of you!!
Very welcome. It is fun and interesting to see how things measure. On the 8500 I was just puzzled that none of the normal spots that do bench tests had done the 8500. Gene had done the SR8012 and AH did a very nice review of the 8500, but no measurements. So it had to be done :)
One thing many don't know is that when you get a piece of gear measured by Amir, he pays return shipping, so you are just out shipping one way.
 

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