It looks like a debate to me.

Roger M RM-9 has 3 feedback settings so you can dial into what your ear brian likes in a 3D world....

And the ear brain is highly sensitive to time and phase... no debate there either... ha

Hi @tomic601

I hate to be the spoil sport here, but I know I'm not that sensitive, and experts I trust also say this.

I believe some people are very sensitive to this issue, but I've never heard a time/phase accurate speaker wow me just because of that.

I point you to this article, which has three different experts on the subject:

https://audioxpress.com/article/zero-phase-in-studio-monitors

Like I said, I know I can't hear this, maybe others can, but I don't think those who can are the majority.

Best,

E

I will argue that we are also more susceptible to damping factor and speaker/cable impedance than we think we are, but I, in a very lage part, agree with Ralphs point, that the distortion profile is probably a large, large factor in likeability.

About that- amplifiers are far and away out in front of speakers in terms of development. One problem here is that no speaker needs more than about 20:1 for a damping ratio (not 'factor' mind you- 'ratio') and many solid state amps have far more than that, resulting in a coloration many audiophiles like called 'tight bass', something that does not seem to exist in the real world.

Roger M RM-9 has 3 feedback settings so you can dial into what your ear brian likes in a 3D world....

Not to put too fine a point on it but it can be seen as obvious that none of the settings would be correct. The RM-9 simply didn't have the gain or bandwidth to support enough feedback to really do the job properly. So any of the settings would have been a compromise.


We used to put similar amounts of feedback in our amps back 30-40 years ago, only to find that it did terrible things to the soundstage and tonality.


You can look at the deliterious effects of feedback on a Bell curve. A small amount of feedback does little damage but has little effect too- no more than about 2-3 dB. 12-20 dB is in the peak of the Danger Zone; so you will experience increasing brightness and harshness from about 4dB up to that point; above 20dB the harshness and brightness heads back to 'normal' but since very few amps have in excess of 35dB essentially 99 44/100s of all amps that run feedback will have a coloration of brightness and will be harsher than real life.

If you've ever wondered why two amps can measure flat on the bench but one is bright and the other isn't, this is why.

Erik - of corse there is a lot more than time and phase... pistonic drivers, low diffraction, impulse, energy storage in the cone and cabinet, reflections from the magnet structure, the list is long ... like a series and patents since 1977

Ralph - yes of course, three positions all incorrect. And they all measure different. RM like you was about learning, the RM9 evolved to MK2, so on. I think some of your  amps are on MK3.3 ?

 My reference amp has single ended output, 5 parts in the signal path, no emitter resistors, no global feedback , liquid cooling, analog circuits for bias and pump control , mechanical truss isolation, ten regulated supplies... and alas is as all things made by man, imperfect.

To review, it is a seminar. All are invited.
It is ONLY billed as "John Atkinson, a panel of pedigreed amplifier designers debate what matters most when it comes to amplifier sound quality."
Expounding on what most of us already know about distortions and hearing does not change that. It might devolve into meaningless hype. It might not.
You'll never know if you're not there because any subsequent reports will be "distorted."

I find the louder the voice in the audio industry, the more likely the stripes are painted on.

I stand by the intent of my original statement:

Amps seem to sound more sensitive to impedance issues to me than the math otherwise suggests.

Peace, @atmasphere

Best,

E

Lovin' your stand Erik.

atmasphere, as someone who designs amps (for many applications), I cannot agree at all with your comment w.r.t. amount of feedback and sounds profile. There are far far too many other factors at play including open-loop bandwidth, compensation network, or just to make it simple, transfer function including load to simplify to an amount of feedback to equate to a particular sound.

Your simplification suggests a marginally unstable system as opposed to an over-damped system.

heaudio123
That's what I'm talkin' ' bout.
I'm more interested in designer input.
I don't care in the least that few members seemingly are that.
Level of interest and disrespecting other viewpoints are mutually exclusive in my book.

I stand by the intent of my original statement:

Amps seem to sound more sensitive to impedance issues to me than the math otherwise suggests.

@erik_squires I was not contesting this, FWIW.

There are far far too many other factors at play including open-loop bandwidth, compensation network, or just to make it simple, transfer function including load to simplify to an amount of feedback to equate to a particular sound.

Your simplification suggests a marginally unstable system as opposed to an over-damped system.
@heaudio123

Correct.


In order to present a nutshell explanation of how feedback is problematic (and also how to use it) the explanation has to be simplified and as much as possible use layman’s terms.


Open-loop bandwidth of course plays directly into gain bandwidth product, and compensation networks inside the feedback network itself and also in the actual signal path are of course important in any proper amplifier design. But the essence of my point is simply this:
If an amplifier has enough feedback, it won’t be bright and harsh, whether tube or solid state. Historically we’ve not seen really such an amplifier- that is why tubes are still around!


IMO most amplifier designers don’t really know how to design a proper feedback loop (as you know its far more than just a simple resistor). Meanwhile the test and measurement folks seem to realize there’s some dirt to sweep under the carpet which is why you rarely see THD analysis with the fundamental much more than 100Hz, with harmonics in the ear’s most sensitive region simply not displayed.

fuzztone - you sound like a sick puppy to me and I am not sure you can be fixed...

I've earned my stripes by being a sought after and sometimes chased after (Get him! That concert was too damn loud!) live sound mixer/producer/destroyer. I've had my stripes ceremoniously ripped off in front of royalty also, along with banishment to an isolated island from which I escaped. Long story...however, I'm firmly in the single ended Tube camp which interestingly is a camp with a single end that sounds like music.

For the record:

• I have a face (just checked...it's still there)

• And I'm not a "hobbyist." My love of music (which propels all my audio systems appreciation), has way more amplitude than that snarky word can convey

Wow. Am I a "faceless hobbyist?" That makes me sad......YMMV.

This thread illustrates so well my love/hate relationship with this site, but also why I spend less and less time here. There are some people on this site who really know their stuff. I learn from them all the time. This thread has a bunch of those. But unfortunately it also has replies that are abusive to other members and ill-mannered. After enduring these for too long, I have decided to report abusive posts with the hope the moderator will put a stop to the abuse. I urge others to do the same, I have seen sites go South when the abuse gets out of hand and the trolls take over. The troll and abuse quotient of this site has multiplied considerably in the decade or so I have been a member. Judging by the replies of some to this thread, I am not alone in being frustrated by those who seem to have nothing better to do than hurl insults.

desktopguy

I'm not a "hobbyist." My love of music (which propels all my audio systems appreciation), has way more amplitude than that snarky word can convey.

What is it about the word "hobbyist" that you think is snarky? There are many more hobbyists in this group - and I'm one of them - than there are professionals. There's nothing wrong with that.

Oldguide...you can report all you want but keep in mind there's a tradition of free speech in some places, and to some a troll is anybody who doesn't agree with their particular point of view. Are you reporting anyone who seems passionate about something you disagree with? A self appointed judge of others is also a troll, and nobody needs to be looking over their shoulder to see if Oldguide the Church Lady is watching for tawdry posts.

Where have you been all these years  ?   Nothing sounds the same  
Let's get that right.  

One thing is for sure. It will not look like anything to me since the event has been rescheduled and I have a previous commitment.
Thanks to their wonderful 'no refund" policy I get to throw my tickets against the wall.

@wolf_garcia , amen to your last post, and thank you for saying it. Enjoy the music.

I'm more interested in hearing the viewpoints of people that have earned stripes in the audio industry rather than faceless hobbyists. Am I alone in this?  

YES YOU ARE.. YOUR the only one...

On these forums who else is here, and what constitutes STRIPES? If I'm reading this correctly, you want, "the PRICKS, and BITCHES, to keep their nasty, I drank to much, I don't feel good, mine is the best, my way or the highway, or I'm JUST AN ASSHAT to keep away from WHAT?  What is the question? or is it all the questions with the inference, "your a friggin moron for asking", or ignored all together.  Is it the response to the questions, or the statements? Refer to the above... Jealousy always brings unkind words.
The quality of the question you ask, can often determine the QUALITY of the answer you receive. 

I mean did someone offend you that much?.. EXPLAIN your position more clearly, and tell the naysayers, to fuc@off , eat shi?, and die.

Works for me... The dickhea#s your speaking of, have a contribution, just having to read between the lines is a pain in the hinderside... Yes means yes, no means no..

Now was there a question, or is this just a "blow off some steam" blog.

Did I miss something... AM I ONE??? Don't be shy... How may I be of assistance. For crying out loud.... IT'S ALL FREE. Then bitch about the service. LOL Don't be shy now, I'm NOT..oh yea!!!!!!!

Respectfully and hopefully with a since of humor.

I'm more interested in hearing the viewpoints of people that have earned stripes in the audio industry rather than faceless hobbyists. Am I alone in this?

Tube or not to tube, is that the question?

Yes and no.. I like both, I like tubes in the mids (only) , I like SS bass and above 12k.  I like tubes from 100hz-12k. 

Faceless hobbyists

“Tube or not to tube, is that the question?”

Not one to niggle but shouldn’t that be tube or not tube? 😳

It should be "tubey or not tubey."

Actually that was not the question.

Actually that was not the question. 

What is the question? ACTUALLY? Yea after another Agonner let me know my input was not what he asked for, I kindly replied "THEN ASK THE RIGHT QUESTION".  My answer had to ANSWER someones question....RIGHT? Even if it was about the planet Venus. Man oh man people are so picky....or PRICKY! is that a word?

Geeezzzz think I'll take up drinkin' might get along with folks easier HERE!!! Tough crowd...

Regards, maybe...

The only question posed was whether I'm alone in being more interested in a live debate about amp designs by amp designers. (NOT tubed vs ss since the panel members are not even determined yet.)The answer has been basically yes. I have no problem with that.
Agonners have commented that they prefer recorded over live as in their recorded responses and published studies. And some have stated that they trust forum members views over professionals, apparently due to some paranoia in believing that designers are charlatans and thieves. Except, of course, those designers that created their owned stuff.

Axpona 20 has been rescheduled if not cancelled.
I am NOT interested enough in it to forgo a planned weekend with grandkids.

I respect all opinions regarding facts.Not so much regarding fantasies, lies and vitriol.

oldhvymec I welcome your input any time.
However I recommend cannabis in lieu of alcohol for "getting along."
It works better for me.

oldhvymec I welcome your input any time.
However I recommend cannabis in lieu of alcohol for "getting along."
It works better for me. 

Well I happen to agree, we are on the same page there. As for the rest I was premature in my assumption it was SS vs Valve. I'm still not quite sure what the forum is for.  But here is the good news. I'm a good sport, let me read and learn. Sounds like politics in one form or another.

Respectfully and with regard

I didn't pay attention to who did it, I just saw bad assumptions everywhere. In the heat of defense I know I made a few.
You'r'e cool.  Stay well.
Groet.