Beyond the Ariel

[gedlee]

Lynn

You are asking me to accept your claims of audibility on faith and I am unwilling to do that since they do not coincide with my own experiences. Further your claims of audibilty here are not supported by scientific subjective tests and go against the findings of virtually all tests done on amplifiers that are. Just because something is measureable does not mean that it is audible, just as things that are audible are not necessarily measured. One must close the loop with valid scientific subjective studies to show the level and significance of each and every claim. I do this in my own work as my publications will attest.

We will have to continue to disagree and I will stick by my accusation that you jumped to conclusions when you listened to my system at RMAF.

[Lynn Olson]

Nudging things back on-topic - although post #1062 was a long laundry-list of transistor-amp woes, most of the problems are in the mid/high region. In the LF region, the biggest remaining gremlin is the long reaction time of the Vbe multiplier to the output-transistor die temperature. In dynamic terms, this means the correct operating current is always a few seconds too late - either too much or too little bias. Since beta and Hfe are affected by temperature, this is not a minor point.

It's too bad the LNPA-150 is out of production - that was one of the few Class AB amplifiers that had a fully regulated output, driver, and input section. It sounded noticeably different than any other transistor amp I've heard, despite the audio circuit being outwardly similar to the old Audionics CC-2. I had the opportunity of buying a pair from Daniel Banquer a few years back, and I should have taken him up on it.

Class D/T amplifiers don't measure that well from 1 kHz on up, but look pretty good at lower frequencies, and are free of the thermal-wandering issues of Class AB amplifiers. From the threads elsewhere on the forum, it looks like TriPath has disappeared, so it's Class D from now on.

One things I haven't done is audition some of Nelson Pass' low-power Class A designs with a high-efficiency speakers. I would imagine either a HF horn or the new double-RAALs would reveal the truth about the amplifier in short order.

As for building my Karna amplifier - um, well, that's a big project. They are a long way from being a commercial product with all the bugs chased out. I'm still wrestling with the best way to heat the 45 and 300B DHT's.

Yup, I'm a subjectivist. Must be all that Buddhism I was exposed to in Japan and Hong Kong - kinda hard to shake off after all these years.

(Note about the "avatar" pix - taken in India in 1991, where the folks at the temple were thrilled when I told them I was a Buddhist. Little did I know that Hindus consider Buddhists one of them - they regard it as just another sect of Hinduism. The original pix showed the red dot they put on my forehead - but I thought that was a little over the top, even for diyAudio, so I Photoshopped it out. Still, the whole audio-guru/avatar image is a bit comical in the context of audio, where people fight such mighty battles over such tiny things. I wonder if the model-trains guys wrangle about O vs HO vs S gauge?)

[LineSource]

Mr Geddes,

Your views on dipoles vs. monopole speakers like your Summa would be very interesting and relevant to the folks following this loudspeaker thread. Personally, I would like to understand what limitations your think Full Range Apogee dipole ribbon speakers have.

[ScottG]

Earl - you are swimming upstream here.

Lynn believes in different sounding amps - as do a MULTITUDE of other participants on this forum. In fact MOST of this forum provides participation for just this purpose, to improve the audibility of their amplifiers for a given application. With the above, OBVIOUSLY many think that crossover distortion and harmonic distortion are only a few factors relating to the audibility of certain amplifiers, and are perhaps factors of less importance. Just one example is "parts rolling" (or using different parts - without substantial objective changes to currently measurable attributes) in an effort to achieve a better sounding amplifier (to them).

Now this statement:

""Well, this is where individual perceptions enter in. Earl Geddes, ... , believes Costco-quality electronics are good enough to exhibit at the RMAF, and anyone who thinks otherwise is fooling themselves, or worse, trying to sell snake oil to the gullible.""

May not be polite.. and yet it might be VERY polite. Odd, no?

First off - you have only enforced the fact that indeed you DO think Costco-quality electronics are good enough to exhibit at RMAF. (i.e. you found an amplifier from Costco that you thought was good enough to use.) This does not of course mean that ANY Costco sourced amplifier is good enough to use, but at a minimum that the one you used is good enough.

Second - in much the same as Lynn *might* be intimating that you personally think that others are fooling themselves, (and there IS another way to interpret that sentence), you appear to support this very notion by suggesting that perceptually people are doing just that. (i.e. "truth in audio", "elevate our illusions" etc.)

So, indeed that statement was apparently both correct and fair to at least some extent. Now was it polite?

Perhaps it wasn't polite, after all most people don't like generalizations made about them. It is however a common practice, and is useful as a means of communication. Most importantly though, it wasn't abusive in a forum context in that it wasn't a "flame".

Then again.. maybe it WAS polite.

Consider the alternative. What if what Lynn heard wasn't simply a function of the cheap amplifier? (..cheap price wise and in overall materials quality.) What if what he heard was at least in part determined by your speakers? In this sense then, he is being perhaps MORE than fair by suggesting that what he found to be at fault lies not with your speaker, but with the associated equipment.

All of this suggests any number of viewpoints - and perhaps the most telling viewpoint is that you choose to view this one comment in so negative an association to you personally, that you felt the need to defend it here..

Furthermore, ask yourself this question:

Did those who suggested you read this thread, suggest this to defend your "honor" on issues pertaining to amplification?

OR -

Were they perhaps suggesting that you add your knowledge of horns in a productive fashion to this thread?

IMO, its the latter.

Finally..

I don't think Lynn ever asked you to take his "claims of audibility on faith". Rather that he has this perspective, and is giving some basis for that perspective, as well as *trying* to help you understand that a GREAT many others share that perspective.

Again, you are swimming up-stream. Rather than saying "you are wrong" to others, try sticking to those topical areas where you can say

"you are right and this is why.."

OR -

"you are right BUT an improvement can be obtained by.."

(..this follows the cliched yet eminently useful phrase and concept of : "If you don't have anything nice to say, don't say anything at all.")

I convey this to you specifically, (well beyond others), because (IMO):

1. You consistently have this problem communicating in forums.

2. You have a lot of very *useful* information to share that can be greatly appreciated by others.

Well, as always - good luck!

[ScottG]

Originally posted by Lynn Olson
I wonder if the model-trains guys wrangle about O vs HO vs S gauge?)

Sadly, they do.

[Teh]

Man, Scott! I don't think that was called for at all!

Does this mean that if one does not, indeed, share the same opinion as the MANY, they are not welcome here?

This discussion is about loudspeaker design, how about we keep it to that?

For roughly a hundred and 4 pages it was just amazing, let's keep it on track. This discussion could continue to be more and more informative and revealing.

Or, it can degenerate into some kind of name calling because someone has tin ears? Wow, that take a heck of alot of certainty, doesn't it? Or, wait a minute, maybe we're all wrong and it's the many with the tin ears?

Heck, I don't know, but, it appears there are those that do. Pitty!

[ScottG]

Originally posted by Teh
Man, Scott! I don't think that was called for at all!

Does this mean that if one does not, indeed, share the same opinion as the MANY, they are not welcome here?

Thats OK.

You can think that if you like.

However,

My intention wasn't to suggest the above statements to anyone but Earl. Nor was it intended to be anything other than constructive to him.

As you specifically mentioned - this thread is primarily about loudspeaker design.. WHO altered that course significantly? Perhaps more importantly, WHO could provide a wealth of information on loudspeaker designs utilizing horns, yet hasn't even broached the subject?

So, no - I don't believe that everyone should "toe the party line" - not by a long shot. But perhaps like you - I do think that the discussion should stay focused on constructive comments, rather then self-defensive posturing on a topic that bears little relationship to the overall thread.

[soongsc]

From a technical point of view, I agree that many things talked about here have not been supported by, measurements, neither have they been supported by explanation based on specific music sources. But I do think that we should not criticize a person, but rather either ask for more information and proof, or prove one wrong.

Trying to argue about who is right or who is wrong really brings no improvement to audio. If each of us can be more specific in what we evaluate, then we will see improvements. I know that many people can get offended when they are backed agaist the wall with questions they cannot answer. I guess we should just learn to deal with how not to feel offended.

From a lisnening point of view, very few people try to identify the specific music source they listened to when they came to a specific conclusion; they do not address the changes in individual instruments in the music and and what difference they hear. The general terms generally used to express the their impressons are so relative that unless compared against a known equipment that the readers are familiar with, there is no way one can know how critical a review the writer had performed.

From a technical point of view, explanations are in terms of mathematically derived values rather than basic physical phenomena and physical rules. Most of these are just index specific to one aspect or measurement method, which may not be the critical factor. Most measurement data are only viewed from a particular perspective and not explored in detail to reveal the critical aspects.

It would also be unfair to ask experienced members to throw out all the information without reserve. I think it's a good idea for each of use to contribute something specific enough for others to repeat the evaluation, and if others come to different conclusions, then we can explore what really is going one.

[soongsc]

Originally posted by Lynn Olson
Hi Earl, your comments are appreciated!

...

Can I hear these things? Not in a 1,2,3 way, but more generally as low-fi sound. It sounds "dirty", with obscured low-level detail. When the problems are addressed one by one, the sonic problems go away too. Bob Sickler and I did this back in 1979. It's not that different than removing a resonance from a loudspeaker - when it's gone, the speaker sounds better. The same applies for amplifiers.

...

I quite agree with many of the aspects described. This speaker related issue is similar with my findings. But in additional to resonance, the distribution and dissipation of energy stored in the driver is also an important aspect that can result in different sonic signatures of speakers. Differences can be observed via CSD plots over a 4ms range and 0.4 ms range.

[Teh]

I'm actually surprised.

I'm half blind and, as a result, my sense of hearing is hightened. I hear what most around me cannot. My dog can hear better than I but I'm not aware of one human being that can hear as I do.

Still, I'm not nearly convinced of my golden ears as some of you. I'm just wondering if this is some kind of ego thing? How are you so very sure?

The point is very simple! There is a sonic signature that "we", that is you, or you or me seem to prefer. I think the point is very simple; let people have what pleases them.

Correct me if I'm wrong here, but hasn't Lynn identified Earl's work as some of the finest in the world in this thread? Does that make him right, and Earl a genius? I'm not a fan of horns, I still share Lynn's original assessment as "honky". Still, it is merely a preference. I'm really enjoying this discussion as Lynn is opening up to new and previously unacceptable approaches. That is a commentary on one's thirst to know. I admire that.

Also, one last thing, with such a "poor" system driving his speaker system, still, Lynn, and others, find the work done by Mr. Geddes as among the finest avialable anywhere in the world, at any price, right?

So, to get back on track; Lynn, what are you using for drivers for the lowest two-three octaves? What kind of Fs do they have and why are you choosing them verses other drivers? Furthermore, how are you going to drive them? Active Crossovers? EQ'd? Assisted? Transform? Servo? Monoblock amps? Onboard amps? Tube amps? How are you going to handle the real power eaters? How are you going to get them to extend to 20Hz?

How will you achieve the crossover you're looking for? What is it precisely that you are looking for with the low frequency part of the crossover?