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Topic: Audibility of Audio Power Amplifier Distortions (Read 66877 times) previous topic - next topic
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Audibility of Audio Power Amplifier Distortions

Reply #50
http://www.madronadigital.com/Library/Mark...3Amplifier.html
Quote
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.


Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.

Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.

cheers,

AJ

p.s., ignoring and evading answers....provide answers also.
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #51
amirm,

I don't have enough experience in amplifiers to really evaluate the arguments here, but the way you address everyone's posts in the most obnoxious, weirdly personal tone littered with creepy unneeded emotes really, really really makes it hard to consider the merits of your arguments.  They are buried under so much foolishness one must really work to even realize they are there, and frankly, given the way they are presented I think few people will even bother.  Which is a shame, you posted some good tests in the other thread suggesting that you are much more serious about this than your posts imply, but I fear the way you choose to express yourself will mean that no one will take you seriously. 

Please consider how the way you conduct yourself will lead others to question your judgement and experience more carefully.  A tiny bit of effort on your part might result in a much better reception.

Audibility of Audio Power Amplifier Distortions

Reply #52
Garbage in, garbage out indeed.  Yet Krab says your work is obscure and his is relevant information!  He doesn't understand that preference can very much be subject to bias.



(sigh)
Do your employees and clients have an inkling of  truly *outstanding*  amounts of time and verbiage you spend puffing up your own ego and waging your inane audio battles on the Internets?

At least spare a few of those many minutes to turn in your pop quiz answer, ok? The task was to quote the final question and answer in Meyer's article.  Unlike this trivial baiting rubbish you've posted above, it's relevant to the topic here.

Audibility of Audio Power Amplifier Distortions

Reply #53
Great Holy Hand Grenade of Antioch, what IS this thread?

It's rather tall, I'd like a second one, now, about this high...
-----
J. D. (jj) Johnston



Audibility of Audio Power Amplifier Distortions

Reply #56
... with a herring!

Audibility of Audio Power Amplifier Distortions

Reply #57
Great Holy Hand Grenade of Antioch, what IS this thread?

It's rather tall, I'd like a second one, now, about this high...



This thread is just getting warmed up, which is taking some time because of the bobbing and weaving by our esteemed guest from Madrona. ;-)

IMO the real fun is over in the thread entitled "Audibility of Typical Digital Filters in a Hi-Fi Playback System, a follow-up to Meyer & Moran?"

The real fun part is where our esteemed guest pukes over Meyer and Moran for not following BS 1116, and then someone dredges up some publications he wrote and posted on his corporate site and asks the same question.  Kryptonite!

There are rumors that Steve Balmer taught classes in dodging and bobbing when being asked tough questions over at MS... ;-)

Audibility of Audio Power Amplifier Distortions

Reply #58
Great Holy Hand Grenade of Antioch, what IS this thread?

It's collateral damage from the explosion of this thread, discussing this paper: Audibility of Typical Digital Filters in a Hi-Fi Playback System

Amir has made claims about hearing both 16/44 HF filtering and Class D amp HF filtering (well, among other things also). I encouraged him (possibly the mods too) to make a separate thread to discuss these Class D amp "listening" tests of his, but he instead used it as an opportunity to create a generic "Amp distortion" thread, so that he could attack his old pal Arny. Rather than defend his claims about "hearing" Class D amps vs AB, etc, as he claimed here: Reinventing the Audio Power Amplifier: Mark Levinson No 53

Hard for me to tell when it's purely diversionary or masochism.

cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #59
Great Holy Hand Grenade of Antioch, what IS this thread?

It's rather tall, I'd like a second one, now, about this high...

Relentless stalking under the guise of scientific inquiry.

Audibility of Audio Power Amplifier Distortions

Reply #60

'Tis a silly thread.

Audibility of Audio Power Amplifier Distortions

Reply #61
Great Holy Hand Grenade of Antioch, what IS this thread?

It's rather tall, I'd like a second one, now, about this high...

Relentless stalking under the guise of scientific inquiry.

No inquiry.  Never seen a bunch of doctors going to a forum where their patients hang out for scientific inquiry.

The thread is for all of you so please don't excuse yourself from the list Chu  .
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #62
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.

Before we go there, I have fully documented Arny and friend's tests here.  Let's make sure you know how to respond to them before we talk about something else.  I will answer on behalf of Arny the questions below and see what you do with them.

Please list your:
Set up, equipment, sound room noise levels, etc.

He explains the source (turntable), speakers and of course amplification.  No mention of sound room noise levels.  And no mention of "etc."

Quote
What AB and class D amps were compared?

He has compared two 200+ watt class AV amplifiers.

Quote
Who/how was the testing run while you "listened".

We don't know who was there when the three of them did the testing.  We have to take their word that the results are as they are and they have "proven" that amplifiers sound different when tested on supposedly transparent performance (THD less than 1%).

Quote
What was the listener training?

I seem to recall Arny saying there was some training but none is indicated in the article.

Quote
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?

No, it was not compliant with  BS-1116.

Quote
Can you post the statistical results?

Sure.  Here they are:



Quote
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?

They did not. They found the cheaper amp to be the better one even though a double blind ABX test is not revealing that way.  That information must have come as a result of post-hoc analysis or the test was not really blind.

Quote
TIA.

cheers,

AJ

You are quite welcome Ammar.  Would be great to see what you do with the type of information you seek.  And satisfy Chu's desire for scientific inquiry. 

Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #63
amirm,

I don't have enough experience in amplifiers to really evaluate the arguments here, but the way you address everyone's posts in the most obnoxious, weirdly personal tone littered with creepy unneeded emotes really, really really makes it hard to consider the merits of your arguments.  They are buried under so much foolishness one must really work to even realize they are there, and frankly, given the way they are presented I think few people will even bother.  Which is a shame, you posted some good tests in the other thread suggesting that you are much more serious about this than your posts imply, but I fear the way you choose to express yourself will mean that no one will take you seriously. 

Please consider how the way you conduct yourself will lead others to question your judgement and experience more carefully.  A tiny bit of effort on your part might result in a much better reception.

I was going to start by thanking you for your advice but it did not work out so well for me last time.

Tom Hanks had a great line in the movie Forrest Gump: "You know, it's funny what a young man recollects, 'cause I don't remember being born. I don't recall what I got for my first Christmas, and I don't know when I went on my first outdoor picnic, but I do remember the first time I heard the sweetest voice in the wide world."

I don't remember most people I run into on forums who use aliases.  But do remember yours because it is the same name as a beautiful (but dangerous) water way where I live called Saratoga Passage.  This is the "sweet voice" I heard from you three years before I joined this forum:


amirm failed spectacularly at comprehending that example chart. That makes him at least clueless about codec testing, and probably stupid as well since its not really that hard to understand if you can use words and understand ideas. (my apologies if he simply does not speak good english and so could not read the chart properly) Hes arguing about codec testing. You know hes ignorant about codec testing. Why are you even having an argument with him?

Point out hes too ignorant to have useful ideas about this and move on.


This thread has 61 posts and 1541 views.  So there are 25 views for every post.  Something tells me there are good number of people who are reading and either find the thread useful or entertaining.  I take either .

Respectfully,
Your Stupid Non-English Speaking New Member,
Amir

Edit: fixed the link.  Now where is that English dictionary....
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #64
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.

Before we go there, I have fully documented Arny and friend's tests here. 


Fully documented? LOL.  Amirs description of it is fully something - fully biased and fully BS. ;-)

One relatively important missing parameter is when the tests that Amir alleges he "Fully documented" took place. Of course he didn't mention that.

Carlstrom, David, Greenhill, Laurence, Krueger, Arnold, "Some Amplifiers Do Sound Different", The Audio Amateur, 3/82, p. 30, 31, also reprinted in Hi-Fi News & Record Review, Link House Magazines, United Kingdom, Dec 1982, p. 37.

The answer is, best that I can recall - 1981. The articles about it were published in 1982.

Questions like the one about BS1116 are pretty strange because BS1116 was originally published in 1994, over 20 years later. Yup, being less than fully omniscient we didn't comply with standards that weren't published the first time until over 20 years later.

http://www.itu.int/rec/R-REC-BS.1116/en

It's like faulting Henry Ford's first prototype car because of the styling of the fenders.

Audibility of Audio Power Amplifier Distortions

Reply #65
Would be great to see what you do with the type of information you seek.

We already know, since you have provided it.
The questions I asked are all rhetorical, because everyone can see your claims about amp testing, like being an objectivist, are a fraud.

Quote
But How Does it Sound, by Amir Majidimehr

OK, lots of technical BS talk to bedazzle the audiomoron, but does any of this impact the sound? You audiomorons may know that there are two schools of thought here. My strawman says all amplifiers more or less sound the same. While I say the exact opposite, with each sounding different like the smell of two different farts. I'll pretend not take a position in that food fight . But instead, speak of a much less controversial issue of pure power delivery.

As a subjectivist I'll prime you up with the trend of less of efficient speakers and somewhat limited power available from our wall sockets, the amplifier can run out of steam before your desire for dynamics does, at least in our minds. This usually translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, less than impactful bass and possibly a loss of pace and rhythm.

In some purely subjectivist comparison testing I have either done, or possibly just made up/fabricated, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price, that we happen to not sell. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant. I know this is the type of moronic rambling audiomorons like to hear, so I feed you.

If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a $50k pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive), not to mention make your wallet as empty as your head. We are happy to let you evaluate them with your own system to see the benefits of this technology.  Seeing, hearing and peddling this amplifier was an eye-opener for me.  I think it will be for you too.


cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #66


Mine certainly was not an 'out of context quote', my quotes were chosen more or less at random where my eye happened to land.  Your quote is from a different sentence, not the same one I pulled mine from.  And you failed to give page numbers for my 5 quotes.

10 demerits.  Smileys and apples get you no credits.

Pop Quiz!:

Quote the entirety of the last question and answer.



Bzzzt!  Time's up Amir.  You failed *again*.


Here's the answer, from Meyer, 1991 'The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier Into A Tone Control?':

Quote
Q: Then what does this say about other combinations of amplifiers and speakers? You got very different results for your three systems.
A: Most speakers are probably more like the one that  produced the curves in Figure 3, but we need more  tests like these to answer that question.  What we've found so far suggests (1) that most  good solid-state amplifiers probably sound identical, or at least very much alike, within their power limits; (2) that tube amplifiers (and solid-state amps designed deliberately to behave differently liek tube amps) will tend to behave differently  with different speakers; and (3) that speakers with strongly varying impedance curves tend to make the two types of amplifiers sound different.


Now, that was written way back in the grunge era.  It summarized the 'objectivist' line  on amplifier difference...qualifications and all.  Yet people like you have brayed since before and after that article, that 'we' say 'all  amps sound the same' , period.  And then you bring up something like Arny's article as a 'gotcha' to knock down your strawman.  Do you see how ridiculous you look to someone who's actually aware of the literature associated with the "Great Debate"?


Here's a scan I made of my copy of the article.  Now you have the *whole thing* Amir, instead of whatever snippets you found before.  You can thank me later...on Teacher Appreciation Day.

https://dl.dropboxusercontent.com/u/2605734...erInterface.pdf

Audibility of Audio Power Amplifier Distortions

Reply #67
Would be great to see what you do with the type of information you seek.

We already know, since you have provided it.
The questions I asked are all rhetorical, because everyone can see your claims about amp testing, like being an objectivist, are a fraud.


Ah, I thought you had no technical/constructive reason.  Now you know why I was not answering you  . 

As to the rest of your comment, I am 1000% comfortable with what is printed on my company's web site.  Here is the article section where you got that amplifier write-up: http://www.madronadigital.com/Library/Library.html.  Much of it is published outside of my company's web site. 

Please allow me to turn the tables on you.  This is the business end of your speaker at AXPONA 2014 high-end audio show:



What the heck kind of nonsense is that?  You took a multi-thousand dollar flat ribbon speaker cable and shorted its outputs for one terminal and another one for the other binding?

What testing had you done that said your amp sounded better with your speakers that way?  Breaking some new ground in the interface between amplifier and speaker Ammar? 

This is the description of the gear from the blogger:

A rack full of ModWright Instruments gear was driving the VSFT-3, including a $5,250 KWA 100SE amp and $3,750 LS100 tube preamp. For sources, AJ had a Modwright modded Sony HAP-Z1ES and Oppo BDP-105. I didn’t get a chance to explore the HAP-Z1ES all that much, but I’m pretty sure that was driving the bus while I was in the room. The mods are pretty similar to what I have in my own Modwright-ed Oppo, but include an external PSU, a tube stage and a completely reworked output stage. $3k gets the mod on your own unit.

MG Audio Design cables were used throughout, including the giant flat ribbon Planus III speaker cables and the silver Planus AG1 interconnects.


$5,250 amplifier?  What testing led you to that selection Ammar?
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #68
I am 1000% comfortable with what is printed on my company's web site.


Great, lets start here
Quote
http://www.madronadigital.com/Library/Mark...3Amplifier.html
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.


You can either provide the testing methods for amp distortions you state you did above, or you're a consummate fabricator. Which was already established more than 5yrs ago.

Quote
Originally Posted by amirm
I have said before that this method does not work for ABX testing. But I didn't perform an ABX test. The testing was AB.

In AB test, the bias substantially tilts toward the louder source. That was not the case here. The winning gear most likely had its level lower by 0.7db.

Also, keep in mind that while I talk about which side was "better," I was not making a fidelity/subjective statement. But rather, looking for specific distortion in DACs. This is different in normal blind tests where people are not told what is being tested and therefore, don't know what difference to look for. This is why I am not moved by how many people have flunked such tests. If they didn't know what material to use, and what to listen for, the results are not interesting.
The one liner that triggered this entire thread was my comment that you can approximate -- not match -- level matching by a two phase process where you increase levels of the losing side to see if it changes the outcome. If it does not, then you have something that perhaps rises to 70% confidence level.

Quote
Originally Posted by Terry Montlick
And you derive this probable number from exactly what statistical test??

Nothing that complicated. I give it one out of three chances to be wrong, based on more than a decade of conducting double-blind and subjective tests and formal evaluations of my hearing. In other words, I know what percentage of time I have made a fool of myself in such tests . Versus being right.

You didn't answer my question on how many blind tests you have been involved in.



Amir, given your long, sordid history of outright (test) fabrications, it makes sense you are satisfied with the similar ones on your sales store site.

cheers,

AJ


Loudspeaker manufacturer


Audibility of Audio Power Amplifier Distortions

Reply #70
I am 1000% comfortable with what is printed on my company's web site.


Great, lets start here
Quote
http://www.madronadigital.com/Library/Mark...3Amplifier.html
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.

OK, we started.  Now what?

And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?

Quote
You can either provide the testing methods for amp distortions you state you did above, or you're a consummate fabricator.

I am a woodworker and now have a fantastic CNC machine.  Last week I fabricated this panel for a client's theater:


I don't wake up worrying what someone says online about what I have written.  And just confirming, you have no electrical engineering degree or work experience constituting the same, yes?
Quote
Which was already established more than 5yrs ago
.
Statute of limitation is 3 years in this field Ammar. 

Quote
Amir, given your long, sordid history of outright (test) fabrications, it makes sense you are satisfied with the similar ones on your sales store site.

I stand behind my work.  Do you stand behind this one or do you prefer that it is hidden from view?



Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #71
OK, we started.  Now what?


Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.

p.s., ignoring and evading answers....provide answers also.

And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?

I'm neither shyster nor $cam peddler, so no.

I am a woodworker and now have a fantastic CNC machine. Last week I fabricated this panel

I doubt that's what you used to get those ABX logs. You certainly didn't mention it when you fabricated these test "results".

I stand behind my work.

Liar, or explain you amp audibility testing work here:
Quote
http://www.madronadigital.com/Library/Mark...3Amplifier.html
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.


Lets see how the non-Hobbyist Amir performed Listening Tests for Audibility of Audio Power Amplifier Distortions
Or tell us why you fabricated yet another subjectivist audiophile believer tale about ML amps you peddle for >$50k.

cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #72
And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?

I'm neither shyster nor $cam peddler, so no.

We will have to be the judge of the former Ammar.  I am clarifying: you do not sell any audio equipment that uses class d technologoy with a switchmode power supply.  Is that what you are saying "no" to?

Quote
Lets see how the non-Hobbyist Amir performed Listening Tests for Audibility of Audio Power Amplifier Distortions
Or tell us why you fabricated yet another subjectivist audiophile believer tale about ML amps you peddle for >$50k.

We will get to that.  Just want to first establish the position of my counterpart.

Would you give us a headline of the last audio comparison test you did?  Don't need all the details.  Just what it was.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #73
I opened this thread, saw that amir opened it and that the very first post sets up another straw man argument, I closed the thread. 'nuff seen.

"I hear it when I see it."

Audibility of Audio Power Amplifier Distortions

Reply #74
We will have to be the judge of the former Ammar.

We are judging you based on your audibility claims and actions. Like this blatant fabrication 5yr ago and now this:
Quote
http://www.madronadigital.com/Library/Mark...3Amplifier.html
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.


Your evasion provides the answers.

I am clarifying: I sell $50k $cam-amps that use class d technologoy with a switchmode power supply and have made numerous shyster claims about audibility in this amp audibility thread

Thanks for clarifying and yes, that's why we're here.

We will get to that.

You're going to admit it was all a fabrication like your +/- 10% DAC tests, or:
Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.

p.s., ignoring and evading answers....provide answers also.

cheers,

AJ
Loudspeaker manufacturer