Class D high frequency problems.

[JRR]

As one class D review after the other garners high praise from our Host, I fail to understand why there isn’t more criticism directed towards there products regarding their nonlinearities usually exhibited above 5khz. Even the top performers are showing merely mediocre THD+N numbers above the +5khz range. Yet, other products met with less enthusiasm seem to perform just as well in that same frequency range.

 

[staticV3]

Is SINAD around 5-15 KHz relevant?

I’m trying to build some active 3-way bookshelves. At this point, I need to decide for amp selection for my high frequency >2.5 KHz. I love Hypex products and will be powering the low end and midrange with hypex modules. I’m a bit hesitant about the tweeter amplification. Most newer class D...

www.audiosciencereview.com

 

[voodooless]

I fail to understand why there isn’t more criticism directed towards there products regarding their nonlinearities usually exhibited above 5khz.

Where?

Even the cheap ZA3 does pretty well:

 

[JRR]

At higher levels.

 

[kyuu]

1) Highly questionable how relevant it is in terms of audibility.
2) Many class AB designs show the same rising THD+N at higher frequencies.

 

[voodooless]

At higher levels.

Luckily you can’t hear up to 45 kHz

 

[JRR]

1) Highly questionable how relevant it is in terms of audibility.
2) Many class AB designs show the same rising THD+N at higher frequencies.

View attachment 427870

Right but they are criticized for it where in the case of Purify, Ncore, ICE it usually becomes a footnote at best.

 

[MaxwellsEq]

As one class D review after the other garners high praise from our Host, I fail to understand why there isn’t more criticism directed towards there products regarding their nonlinearities usually exhibited above 5khz. Even the top performers are showing merely mediocre THD+N numbers above the +5khz range. Yet, other products met with less enthusiasm seem to perform just as well in that same frequency range.

It's common for distortion to rise with frequency in any amplifier.

 

[kyuu]

Right but they are criticized for it where in the case of Purify, Ncore, ICE it usually becomes a footnote at best.

What do you mean?

Commentary is pretty much identical: non-linearity at higher frequencies is noted, but not harped upon.

 

[JRR]

Luckily you can’t hear up to 45 kHz

But I can hear 10khz and 15khz. Doesn’t IMD have the potential to alter the fundamental?

 

[voodooless]

But I can hear 10khz and 15khz. Doesn’t IMD have the potential to alter the fundamental?

But we already established that there are generally no issues at those frequencies: https://www.audiosciencereview.com/...-d-high-frequency-problems.60726/post-2224041

Anyway, the topic @staticV3 linked already covered all of this just fine.

 

[DVDdoug]

Don't over-estimate your ability to hear distortion. And remember speakers are almost always orders of magnitude worse than electronics.

I've NEVER heard distortion from ANYTHING unless it was broken or overdriven. (With the exception of vinyl records where you might get distortion without anything being specifically defective or broken.)

 

[oleg87]

Keep in mind that in real material as opposed to test tones, there will generally be little power at high frequencies relative to stuff below 10khz. Not sure most tweeters could even handle the power levels that would make a class D amp underperform for any significant amount of time. It's certainly an "on-paper" weakness of some class D stuff but I suspect of vanishingly little audible consequence.

 

[OldHvyMec]

M

But I can hear 10khz and 15khz. Doesn’t IMD have the potential to alter the fundamental?

May I ask what you would recommend or that you use? Does it actually bother your listening experience?

I ask because I prefer valve amps. I'm one of those who crave distortion (as some people put it) and because of that I can listen for hours on end vs
30-45 minutes at most with amps like SST or the zero feedback models; Ampzilla being one of those.

At minimum a valve preamp. It seems the older the better. Add tone control and I can listen for days on end and do from time to time.

EX: C20, C11, C22 or even a Cary Audio SLP-05 or 98 with class Ds. I use NC500 oem with Nord Buffers (which I hear very little difference if at all)

The early ICE products EX: Wyred4Sound SX1000 (no R) are like taking a shower with a raincoat on, they are so sterile and the background is so dark.

Pass designs and the newer Atmasphere class Ds are simply music to my ears and one of the few SSs that cause ZERO fatigue as long as I can tweak the
HF a bit on the types of speaker drivers I use in a moderately treated room for HF boil.

What would you say is the ultimate amp is in your opinion? OR is this just an observation with no practical purpose other than noticing the chip in the paint
on a fender-skirt (so to speak) while looking at a Rolls Royce Silver Shadow?

I'd be interested in hearing your preference, vs looking at a chart.

With great regard! The OHM

 

[antcollinet]

At higher levels.

The multitone plots given above show all the distortion components that exist in the audible frequency band. I fail to lose sleep over anything I can't possibly hear.

 

[antcollinet]

But I can hear 10khz and 15khz. Doesn’t IMD have the potential to alter the fundamental?

No : distortion generates additional frequencies at multiples of the fundamental. The fundamental stays as it is. That is what fundamental means.

 

[JRR]

The multitone plots given above show all the distortion components that exist in the audible frequency band. I fail to lose sleep over anything I can't possibly hear.

They are given at 5W which coincidentally is the threshold at which THD+N starts to rise dramatically for several class D designs. Do you have an example at 40w? Also, it would be telling to know which 32 tones have been utilized. But even if they are a fair representation of the entire audible spectrum 5W isn’t enough to excite a purify or Ncore design as far as I can tell.

It is my understanding that IMD indeed can produce harmonics much closer to the fundamental than simple harmonic distortion and its integer multiples of the original signal's frequency. Thus there is probably more to the story than those graphs and in my optics the test sampling seems rather selective.

 

[JRR]

M

May I ask what you would recommend or that you use? Does it actually bother your listening experience?

I ask because I prefer valve amps. I'm one of those who crave distortion (as some people put it) and because of that I can listen for hours on end vs
30-45 minutes at most with amps like SST or the zero feedback models; Ampzilla being one of those.

At minimum a valve preamp. It seems the older the better. Add tone control and I can listen for days on end and do from time to time.

EX: C20, C11, C22 or even a Cary Audio SLP-05 or 98 with class Ds. I use NC500 oem with Nord Buffers (which I hear very little difference if at all)

The early ICE products EX: Wyred4Sound SX1000 (no R) are like taking a shower with a raincoat on, they are so sterile and the background is so dark.

Pass designs and the newer Atmasphere class Ds are simply music to my ears and one of the few SSs that cause ZERO fatigue as long as I can tweak the
HF a bit on the types of speaker drivers I use in a moderately treated room for HF boil.

What would you say is the ultimate amp is in your opinion? OR is this just an observation with no practical purpose other than noticing the chip in the paint
on a fender-skirt (so to speak) while looking at a Rolls Royce Silver Shadow?

I'd be interested in hearing your preference, vs looking at a chart.

With great regard! The OHM

I’m not recommending anything specifically. I’m questioning some of the practices used on here that don’t make sense to my simple laymans brain. In the pursuit of truth my objective is to learn about a subject about which I am passionate.

I would recommend against Tubes, pass, vinyl and other verifiable inferior coloration factories. The music is beautiful enough by itself and if you are relying on those to get your sonic desires fulfilled you haven’t explored camp rational enough.

 

[Doodski]

pass

? What is that?

 

[JRR]

? What is that?

PASS labs. A famous producer of “flavored gear”.