Total Harmonic Distortion Perceptibility

[Greswald]

I was looking at the Yamaha WXA-50 & the Marantz PM5005.

The Yamaha has a Harmonic Distortion 0.02%, The Marantz 0.01%

I then took a look at the Marantz ND8006 with a
Total Harmonic Distortion 0.00002

How perceptible is the difference between the WXA-50 to the PM5005 and finally the ND8006?

Are these values already so low that I won't be able to tell the difference or is there a giant leap in quality with the ND8006?

 

[KenM10759]

Looks like the Marantz ND8006 is a player only, not putting out an amplified, speaker level signal. That's why it's so much lower in distortion. Most it comes from the power amp section of the other two.

No, I sincerely doubt you'd hear the difference between those two.

Incidentally, my little NAD D3020 integrated amp has a THD spec of 0.005%. I can't say it actually sounds any cleaner than my NAD T758 receiver with it's 0.08% rating, but my heart wants it to.

 

[Swerd]

I was looking at the Yamaha WXA-50 & the Marantz PM5005.

The Yamaha has a Harmonic Distortion 0.02%, The Marantz 0.01%

I then took a look at the Marantz ND8006 with a
Total Harmonic Distortion 0.00002

How perceptible is the difference between the WXA-50 to the PM5005 and finally the ND8006?

Are these values already so low that I won't be able to tell the difference or is there a giant leap in quality with the ND8006?

For amplifiers, integrated amps, or receivers it is widely accepted that total harmonic distortion (THD) of less than 0.1% cannot be heard. This is easily achieved among nearly all amps.

For what its worth, when tube amps were the norm, THD of less than 1% was considered good.

 

[lovinthehd]

Keep in mind your speakers have far more in any case. Try this article http://www.audioholics.com/loudspeaker-design/audibility-of-distortion-at-bass/total-harmonic-distortion-thd

 

[TheWarrior]

I have to appreciate that this forum has people concerned with a hundredth of a percent of anything!

 

[Verdinut]

Except for some golden ears, if THD is below 1%, I strongly doubt that people will hear it if it is not accompanied with some sort of noise. As already mentioned by HD, speakers produce more distortion and if it fits within a certain limit, we tolerate it without getting listener's fatigue.

Most of the people who say they can hear distortion of less than 1% are exactly the same ones that believe they can hear differences between speaker cables with the same resistance ranges, but we know for a fact that it is not the case.

 

[PENG]

Aside from the magnitude, some argued that odd order harmonics are more annoying while others argued the opposite. I found Nelson Pass's website covered this topic quite well.

Take a good read
HERE

Interesting to note he found some prefer 2nd, some prefer 3rd, indicating that this is another highly subjective topic. In any case, I think people like Nelson Pass exaggerated the effects of THD <0.1% If it is THD, it really doesn't matter if you prefer even or odd order harmonics, it's just too low to annoy..

 

[highfigh]

I was looking at the Yamaha WXA-50 & the Marantz PM5005.

The Yamaha has a Harmonic Distortion 0.02%, The Marantz 0.01%

I then took a look at the Marantz ND8006 with a
Total Harmonic Distortion 0.00002

How perceptible is the difference between the WXA-50 to the PM5005 and finally the ND8006?

Are these values already so low that I won't be able to tell the difference or is there a giant leap in quality with the ND8006?

You'll never hear a difference because of the distortion. In the '70s, a lot of the receivers that are fetching far more than they're really worth were in the .1%-.5% THD range. Integrated amps and separates were better (some were MUCH better), but unless it was a lot more expensive, the specs weren't very good.

Nobody really cared until the magazines created the "specs race" and that's when it got silly.

 

[slipperybidness]

From a design standpoint, <0.1% THD + Noise should be the goal, more than 1 book on amplifier construction gives this as the target spec.

Does not address the "what is audible" argument necessarily, just a design goal.

 

[Bucknekked]

Nobody really cared until the magazines created the "specs race" and that's when it got silly.

This is a good point regarding measurable items. We often don't know when we approach a task what the key variables are. Often, far too often, the items we can measure and record become important because we can measure and record them. Not because they actually are the important items, but, something about being able to measure and record and item gives it stature.

In our hobby there are lots of measurements that fall in to this category. And for the scam artists it is exactly the opposite tactic they take: you can't measure this stuff, but its obvious if you listen.

I am no expert on these technical measures. That's one reason I come to the AH forum, there are folks who are that hang out here. They can sort through the wheat and chaff. Just because it gets listed on the side of the cereal box as a cool number doesn't mean it really is important.

 

[slipperybidness]

This is a good point regarding measurable items. We often don't know when we approach a task what the key variables are. Often, far too often, the items we can measure and record become important because we can measure and record them. Not because they actually are the important items, but, something about being able to measure and record and item gives it stature.

In our hobby there are lots of measurements that fall in to this category. And for the scam artists it is exactly the opposite tactic they take: you can't measure this stuff, but its obvious if you listen.

I am no expert on these technical measures. That's one reason I come to the AH forum, there are folks who are that hang out here. They can sort through the wheat and chaff. Just because it gets listed on the side of the cereal box as a cool number doesn't mean it really is important.

For amps, the key (most critical) metrics are the THD+N and the Continous Power Output Over the full Audio band. Unfortunately, few mfgs publish the continuous rating. S/N is pretty high on the list for an amp too, but it is a critical metric for pre-amps.

 

[highfigh]

In our hobby there are lots of measurements that fall in to this category. And for the scam artists it is exactly the opposite tactic they take: you can't measure this stuff, but its obvious if you listen.

I am no expert on these technical measures. That's one reason I come to the AH forum, there are folks who are that hang out here. They can sort through the wheat and chaff. Just because it gets listed on the side of the cereal box as a cool number doesn't mean it really is important.

WRT the bold part- That is, if you're ears are good enough. They sometimes try to make people feel inferior when they can't hear it, so they buy the thing, anyway.

Maybe comments like 'It's really, really good!', 'It's just that easy' and 'As seen on TV' could be used for AV equipment.

 

[highfigh]

From a design standpoint, <0.1% THD + Noise should be the goal, more than 1 book on amplifier construction gives this as the target spec.

Does not address the "what is audible" argument necessarily, just a design goal.

Ever heard of the Power Cube for amplifier measurement? I think they should use that for everything.

When I did car audio, some manufacturers used this for their amps, to show that they wouldn't puke when the going got tough (difficult loads) and because some companies were having a lot of fun playing with the specs. We used to refer to the power specs in the manual as 'Sony Watts', say that something put out 100W (JBF) or 100W (WLS). JBF stood for 'Just Before Fire' and WLS stood for 'When Lightning Strikes'. Rockford Fosgate and MTX were the two main users, partly because they were in stiff head to head competition and because each had lost engineers to the other, which was a tricky situation because the design patents were owned by the designers, not the companies.

https://www.ap.com/technical-library/measuring-power-amplifiers-with-reactive-loads/

 

[mtrycrafts]

Ever heard of the Power Cube for amplifier measurement? I think they should use that for everything.

...

What else is it good for besides amps?

 

[highfigh]

What else is it good for besides amps?

I think that's about it- a dedicated device, to measure the amp's ability to drive difficult loads and verify or deny a manufacturer's claims.