Audiophiles, generally don't like class D amps!

[FrankW]

the only reason I've experienced this is some sort of personal bias un Related to what I actually see-hear.

FIFY

 

[Porter]

Yes, since all you've claimed is viewer belief fatigue. Trust your ears for once, not your eyes-beliefs.
If you can't, we all understand.
Shifting Burden of Proof in 3,2,1...

I claimed no such thing. I started from listening (and enjoying) for many months, but began noticing issues with fatigue. I then started from the problem, and then worked back towards a possible cause, by changing one thing in my system at a time and then waiting weeks to see if things changed or improved with the amount of listener fatigue I experienced.

Without a second person to set up and validate blind A/B testing, it's the only way I have to test any variables. Plus, a short blind A/B test would likely not draw any conclusions anyway because it's a sensory issue that takes time to develop and notice. It's a bit like spending time on a boat in the sun. At first everything seems great, but eye strain sets in eventually without sunglasses.

I went through a bunch of iterations, to my wife's annoyance. It was irritating and surprising to me that the specific interaction that was consistently problematic was the combination of the M10 driving the high frequency section of the Klipsch. I even swapped back several times because I kept second guessing my own experience, only to have it re-validated.

So I guess you folks can continue to smugly condescend about "science" all you want, but I feel like I made a reasonable effort here. If that's insufficient for you, well, that seems like it's on you.

 

[FrankW]

I claimed no such thing. I started from listening

Wrong. You started and finished viewing-believing. All on you. The end.

 

[HarmonicTHD]

Neither is belligerent, smug, dismissive refusal to recognize (or even tolerate) the subjective experiences of other people, yet here we are.

I think it was explained many times to you in good faith that what you heard is real for you but does not reflect reality as we are all subject to biases. Only level matched blind test will tell the objective truth whether the difference is your gear or your brain (biases) but as you keep fighting this. So be it.

No need though to get personal and insulting though.

 

[SIY]

Neither is belligerent, smug, dismissive refusal to recognize (or even tolerate) the subjective experiences of other people, yet here we are.

You make the all-too-common category error of conflating "subjective" with "uncontrolled." It's a nearly universal mis-definition in fashion audio, and it prevents clear thinking. They are NOT the same thing.

I will confess that I'd like to beat every audio writer who enstupidates his audience that way with some 12 gauge speaker cables.

 

[Deleted member 48726]

Why would other amps "mask" the sound if they have equivalently flat frequency response and plenty of power? Wouldn't that be something visible on the test bench during a simple frequency sweep?

Maybe the amplifier has rising response in high frequencies like some class D's have. It is a thing to take in account..
Maybe it misbehaves with certain complex loads too?

Amps can be load dependent.

 

[SIY]

Maybe the amplifier has rising response in high frequencies like some class D's have. It is a thing to take in account..
Maybe it misbehaves with certain complex loads too?

Amps can be load dependent.

I have that amp. It doesn't.

Frequency response errors are relatively easy to pick out in controlled conditions, and Porter has already stated that he wouldn't be able to tell the difference with controls applied.

 

[Deleted member 48726]

I would say most small to medium powered amplifiers, with good to excellent measured performance, when run at somewhat elevated levels into typical modern, low efficiency speakers will be experiencing clipping events on regular basis. Clipping audibility and severity varies massively from amplifier to amplifier.

This is important. And I am absolutely sure many clip their amps on a regular basis. They just don't notice.

 

[Deleted member 48726]

I have that amp. It doesn't.

Frequency response errors are relatively easy to pick out in controlled conditions, and Porter has already stated that he wouldn't be able to tell the difference with controls applied.

Has he? Where?

 

[nygafre]

Has he? Where?

Yes he has. Post #417, page 21.

 

[Mart68]

Maybe the amplifier has rising response in high frequencies like some class D's have. It is a thing to take in account..
Maybe it misbehaves with certain complex loads too?

Amps can be load dependent.

I have two different Krell amplifiers here, neither is load dependant, yet they don't sound the same to me.

It's possible that one or both are not working to specification or that it's in my head. I can't say definitively either way so I just use the one I prefer and forget about it.

I think that in this situation the one fact we have is that Porter is not happy with the sound when using the class D. Since a proper blind test over a prolonged period is not going to be practical and a comprehensive measured evaluation of the performance of this particular unit with the Klipsch speaker - that would no doubt show the issue if there is indeed one - isn't going to happen, we will never know.

Just use the amp that's preferred. And be aware that this specific experience is not evidence that there is an inherent problem with class D sound.

 

[antcollinet]

Bench measurements of electronics are a great data point in the search for good gear. But some seem to believe that bench measurements are the ONLY thing that are knowable, and all human qualitative perception is a series of baseless lies.

No, that is not the case, science (and this site) welcomes subjective information. But we do know that all human perception is subject to cognitive biases. And as such without controls in place they cannot be trusted. No one is lying about what they hear, but also no one is able to separate what is real (actually in the waveforms arriving at the ear) or what is being modified by the subconscious 'processing' done by the brain before the sound reaches our conscious perception.

It is why controlled blind testing is the standard in ALL scientific investigations into human perception. No field is immune from needing this - including audio.

We literally cannot trust what we hear without the controls. This is particularly true when real differences as small and difficult to detect.

 

[Deleted member 48726]

Yes he has. Post #417, page 21.

Oh. I see. But then I'm a bit confused..

 

[Bob from Florida]

Let's take an extreme example to draw parallels with your reaction.

Many people who have tinnitus hear sounds that do not exist. The first times that this happens in their life, they don't realize that the sound is only in their mind. Instead, they swear that they really heard such-and-such.
Sometimes, the sound that they "hear" is one that simulates danger, and the person with tinnitus will have the appropriate fight-or-flight reaction; adrenaline begins pumping, the heart rate increases, and sensory acuity increases.
A medical team will examine the patient and normally suggests (diplomatically) that the sound the patient hears does not exist in the real world, but only in the patient's mind.
At that point, many patients become belligerent, and swear up and down that the sound was real. They want to reject the medical diagnosis. This reaction is fairly normal, and has been observed for a great many years. However ...... only a test can resolve the issue. After all, until tests are run, the medical team (technically) has only possibilities on the table. They know that tinnitus might be the problem, but then again it might be something else. Tests give them proof, and they don't need to depend on guesswork.
Some patients (sadly) will not cooperate with the medical team. They think that a diagnosis that the sound is, as they defensively point out, "all in their head" is insulting and demeaning.

The medical (scientific) prognosis is not insulting, and it's not demeaning.

The condition is real, it can be identified (and even sometimes resolved) with scientific tests, providing the patient cooperates. But if the patient does not cooperate, who is the loser? Who suffers? Not the medical team. Only the patient.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

I'm not saying that you have tinnitus. I'm simply drawing parallels between your reaction and the well-known reactions of some other people.

You're not being insulted. Disagreement does not constitute a personal attack. It's part and parcel of legitimate scientific skepticism. Our rejection of subjective impressions is not belligerent, smug or dismissive. It's simply a part of a process that is bounded by dispassionate logic and discipline.

It's a process that ultimately benefits all of us ......... including you.

Jim

If I can add something to the above. The bedside manner of the medical professional often makes the difference in the acceptance of the test results. Not all responses on this forum display the same "bedside manner" you just demonstrated with your reply.

 

[Deleted member 48726]

No need, seeing Class D amplification is one of many things that can trigger audiophile psychogenic symptoms, such as fatigue, etc.
Salivating when seeing a MQA blue light on DACs is another. The list is endless, not confusing at all.

My point was that I'm confused what the user in question means. It seems to me that there is claim that there is difference but at the same time that the user cannot hear a difference..!?? -I may have misread.

 

[GXAlan]

What is it that these people are experiencing? They can't all be wrong can they?

Everyone likes to sling names, but I would propose something else.

I had the PM-11s2 and the PM-10 (reference Class AB and reference Class D).

The PM-10 was more sensitive to ground loops in my testing which would suggest that it is more sensitive to ground loops in a true complex system.

Once I could identify the ground loop between components, the PM-10 took the lead.

The PM-11s2 had slightly lower noise than the PM-10 but the PM-10 was preferred overall in repeated testing. Class D can generate IMD at higher powers unless it’s the current latest designs or the bridged design of Marantz.

The ground loop is the real issue. We assume a ground loop is a super loud 60Hz hum, but it can be a lot more subtle. I couldn’t really generate a ground loop with the PM-11s2 but I easily could with the PM-10.

Time and time again, my answer is simple. If you think you hear something or you want to understand why others hear something, easy step one is buying a calibrated microphone and easy step two is getting a nice ADC.

 

[Ricardus]

Mild irritation at the sound and a desire to turn it off, or listen to something else.

I get that when I listen to Rush, so is that the same thing?

This is wildly vague. This description is completely meaningless. Maybe you're just bored?

It's not a myth. This is a thing that has been really extensively researched, particularly in military radio and signals operations. It's also a huge deal in professional studio environments, where people listen critically for many hours a day as part of their full time job. Most studio monitor manufacturers reference the reduction of it specifically as a design goal.

No, it's not a myth.

It's expectation bias. Someone once told you class D was "fatiguing" and now when your brain knows you're listening to class D, almost as if by magic, you get fatigued.

 

[Ricardus]

Here's an interesting thing... why would a company like Genelec, renowned for their active monitor technology and audio fidelity, use differential amp topologies (Class D for low and mid drivers, Class AB for treble) on many of their flagship full-size monitors?

See here: https://www.genelec.com/main-studio-monitors

What exactly does this prove? This is you in search of anecdotal evidence to support something that doesn't exist.

In fact why don't you email Genelec and ask them and report back to us.

 

[Ricardus]

If it's just some sort of confirmation bias, wouldn't the peeking sway me toward liking the Class D more? I mean I have a lot of money invested in the Class D being good, and zero interest in additional box-shaped devices in my living room that I then have to explain to my wife. I personally don't give a flying F in a rainstorm about the technical differences, though I do generally understand them. What I'm saying is that this is not ideological for me. I genuinely would prefer for the Class D amp to be ideal for my scenario, because it is dramatically more convenient for my life by being small and highly integrated in function.

Because you don't understand confirmation bias.

This came up in a pro audio discrete op-amp shootout I was discussing on a different forum some years ago. One of the DOA designers talked about how he wanted to use surface mount components to save money, but on every (not blind) listening test the through-hole devices always won.

Someone mentioned that his bias was making him choose the through hole over the SM, and he refused to believe it because after all he "wanted" the SM to win to save him money (kinda like you "want" class D so your wife won't yell at you).

But that isn't how it works. He's around 60 years old, and since he was probably 10 he's used through hole, and been told that discrete through hole "sounds" the best and it's been reinforced by the bubbles and communities he's surrounded himself with.

Wanting to save $1 per device on components isn't going to be able to undo 50 years of conditioning that "through hole sounds better."

This is why the tests need to be double blind.

 

[GXAlan]

Here's an interesting thing... why would a company like Genelec, renowned for their active monitor technology and audio fidelity, use differential amp topologies (Class D for low and mid drivers, Class AB for treble) on many of their flagship full-size monitors?

See here: https://www.genelec.com/main-studio-monitors

Class D is like describing an electric car. Are we talking about a golf cart or a Tesla Plaid/Rimac hypercar?

I have owned several topologies
Class A mosfet
Class A 300B SET
Class AB bipolar, mosfet
Class AB, tubes
Class B/Unity Coupled tubes
Class D, ICE, S-Master HX, UcX, HypeX NC252MP, NC500OEM.

Until recently, Class D was very sensitive to load, particularly for the high frequencies.

Your Tweeters and a Class D Car Audio Amplifier Might Not Get Along

If you’re geeky like me, you might have noticed that some tweeters don’t sound good with Class D amps. This article explains why.

www.bestcaraudio.com

This is why Class AB can make sense. These class D implementations, which includes the classic Pioneer Elite ICEamp products, might account for “fatigue” if you have chronic elevated treble and why other owners of the same amp (but different speakers) do not report this issue.

This load dependence is not an issue with modern designs.

I preferred the Class AB Yamaha MX-A5000 over a Class D HypeX NC252MP. I preferred the bridged Class D NC500OEM in my PM-10 over the Class AB PM-11s2 over the class A PM-90 and have the measurements to show the pros and cons.

I found the Class A Accuphase to sound very good but it was starting to show signs of failure, so I sold it.

Again, everyone likes to call others names and blame everything on sighted bias, but there might be a nugget of truth to stories.

Blindly saying that all Class D is fatiguing is just as bad as saying that all Class D fatigue is sighted bias.