The high-frequency attenuation issue of Class D AMPs.

[jayapple]

Usually, Class D AMPs rank high in the AMP rankings, and many of them are star products.

However, the frequency curves of these products will rapidly decline at high frequencies. Unlike this sharp drop, Class A/B AMPs have a relatively gentle slope at high frequencies. Many tests have demonstrated this problem.

Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies. This seems to be a common problem.

What causes this result? Is there a way to remedy it?

 

[boXem]

it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies.

That seems to be quite a bold statement. Usually fatigue is caused by excess of high frequencies, not a supposed lack of.

 

[NTK]

However, the frequency curves of these products will rapidly decline at high frequencies. Unlike this sharp drop, Class A/B AMPs have a relatively gentle slope at high frequencies. Many tests have demonstrated this problem.

Why is this a problem? Have you noticed how rapidly digital signals decline when near the Nyquist frequency, say, for CD at > ~20 kHz? If it is a real problem, then CD audio will simply be unlistenable.

 

[solderdude]

-3Usually, Class D AMPs rank high in the AMP rankings, and many of them are star products.

However, the frequency curves of these products will rapidly decline at high frequencies. Unlike this sharp drop, Class A/B AMPs have a relatively gentle slope at high frequencies. Many tests have demonstrated this problem.

View attachment 455824View attachment 455828

View attachment 455829


Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies. This seems to be a common problem.

What causes this result? Is there a way to remedy it?

so Purify (-3dB) = 60kHz, Apollo (-3dB) = 70kHz, Topping = (-3dB) = 110kHz (not class-D b.t.w.).

And -3dB 60 kHz is an issue because ... ?
Then you would have to wonder how many recordings actually have (audible) content > 50kHz and which speakers in which rooms can actually produce that.

Nah ... chances are when using a cheap class D that has a speaker connected to it that >8ohm > 10kHz then you might get a few dB peaking which might be audible to young ears..

 

[sq225917]

What problem

 

[Tell]

I don't know how old you are OP but I'm positive that you can't hear even up 20kHz, so it's really unclear what you are compaining about.

 

[voodooless]

Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies. This seems to be a common problem.

Citation needed!

 

[Matias]

Wow. At least this is new FUD about class D that I had not read about yet (link to the usual ones), so points for creativity!

 

[BeeKay]

this problem

Which is in real world terms?

These amps easily cover 20kHz plus. I can hear up to 15kHz, which isn’t that bad being in my 50ies. Beyond that - nothing.
And unless you are a bat there is nothing beyond 20kHz for you.

 

[MaxwellsEq]

Many tests have demonstrated this problem

Please provide evidence that this is (as you claim) a problem.

"Extraordinary claims require extraordinary evidence"

Extraordinary claims require extraordinary evidence - Wikipedia

en.wikipedia.org

 

[BeeKay]

Please provide evidence that this is (as you claim) a problem.

"Extraordinary claims require extraordinary evidence"

Extraordinary claims require extraordinary evidence - Wikipedia

en.wikipedia.org

 

[Matt_Holland]

Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies. This seems to be a common problem.

What causes this result? Is there a way to remedy it?

What you claim is the large part of the reason for the “tense” sound (whatever that means) is completely unfounded as shown by the other comments.

What do you mean by “tense” and what other reasons do you think cause such an effect?

 

[Grotti]

"Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue"

So you suggest (without proof of course), that Class D amplification is not "High-Fidelity"? That's nonsense. AFAIR there were (are) traditional AB amplifiers limiting their bandwidth on purpose (Exposure, Naim and others). Too lazy to look up the specs of the mentioned amplifiers, but I am pretty sure, you can do the search by yourself.

 

[boxerfan88]

What causes this result?

because a low-pass-filter is implemented at the output of the class-D amp to reject the switching noise. the slope of the attenuation depends on the LPF design.

Is there a way to remedy it?

nope. if LPF is removed/not implemented, then the amplifier switching noise will be dumped to the speaker. the tweeter might suffer.

 

[Mort]

Horse dead yet?

 

[JiiPee]

Many people think that the sound of Class D AMPs is high-fidelity, but it is very tense and can cause ear fatigue. A large part of the reason for this is the rapid attenuation at high frequencies. This seems to be a common problem.

What causes this result? Is there a way to remedy it?

Question 1: What causes this result?
Answer: Insufficient cognitive capabilities of those many people, who think that such problem exists.

Question 2: Is there a way to remedy it?
Answer: I don't think there is a remedy to human nature.