John Curl's Blowtorch preamplifier part II

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Anyway, I thought that Youtube video had a gem in it too: It always amazes me a great deal when people on the one hand fully accept that 'what I hear is what I hear', and absolutely refuse to entertain the possibility that their perception is at odds with reality. While on the other hand their perception fools them again and again, big time, every time they listen to stereo.

HA! Too true!

se
 
It always amazes me a great deal when people on the one hand fully accept that 'what I hear is what I hear', and absolutely refuse to entertain the possibility that their perception is at odds with reality. While on the other hand their perception fools them again and again, big time, every time they listen to stereo.

Its almost as if you Jan have a 'reality religion' in that you'll talk about 'reality' but never, ever put up evidence for it:p Gives me a chuckle every time...

Giggles apart, I'm calling you on it. Put up some evidence for this claimed 'reality' beyond people's perceptions.
 
It is well known that sight of what is the apparent source of the sound makes hi fi reproduction easier. Just close your eyes when playing back a video and not the hearing difference.
What we TRY to do in hi fi reproduction is to design our audio equipment to allow the clues as to how the music was made to be detected by listening only, since that was all we had for many decades. Therefore, a question like how many hands are clapping behind the singer, might be at test for resolvability in a listening test.
 
I hope that we can go forward and the people who think that my associates and I are not on the right audio path will just find something else to do.
Audio reproduction is the capture of sonic 'reality' and it can be done with amazing quality sometimes, and be amazingly lousy at other times. Over the many decades, it does not seem that we have made as much progress as computers, for example, have. However, I think this is because of the LACK OF ENGINEERING in many audio products, especially by name companies, because the engineers designing the audio equipment are continually told that nothing matters and that double blind listening tests prove this so. I agree, that if the double blind listening tests are right, we should find something else to do. However, in my life experience, I can hear differences, and even improvements in audio reproduction, at least with the designs that I am associated with, so I will continue onward.
 
It is really a matter of trusting yourself, rather than be pushed around by others. Over the years, I have lived through a lot of audio marketing, it hasn't been very helpful, in general.
Going back 60+ years ago, we listened to vacuum tube radio consoles that usually had a wooden cabinet, a fairly large speaker, and were mellow sounding. Listened to them for years. Then the '50's brought us more compact record consoles, usually without radios, to play our records, 78,45,33, and even 16. Usually a pair of 6V6 output tubes and a couple of speakers. Worked for Chuck Berry records, but a little weak for classical. OF COURSE it was mono.
Hi fi was a very specialized craft then, I only knew a couple of people who thought about hi fi in those days.
However, the '50's made some pretty good used equipment for the '60's, because audio marketing INSISTED that you go solid state and stereo. That is how I got my AR-1 loudspeaker, Dyna MK3 60w tube power amp, and Dyna pas2 preamp. I certainly could not afford them new, making perhaps $2/hr at the time, so it was fortunate that it was on the used market. My friend at the time, and now my business partner, dropped out of college and got a REAL job, as an electrician. We got him a pair of AR-3's, a pair of Dyna MK3's and a Dyna preamp, new, as he had more money to spend. I never liked the 1/2 ping-pong ball tweeter, however, on the AR-3.
It took me years before I heard my first K-horn. Well, I got one, in time, it was certainly an improvement over the AR-1, BUT that path differences (proven by everybody and his brother at the time to be sonically undetectable) started to annoy me, but I DID like the low FM distortion and high power output. By 1970, when Richard Heyser, FINALLY was able to give his talks at the AES, we knew that we had to fix the path length differences. More later.
 
We got him a pair of AR-3's, a pair of Dyna MK3's and a Dyna preamp, new, as he had more money to spend. I never liked the 1/2 ping-pong ball tweeter, however, on the AR-3.

It took me years before I heard my first K-horn. Well, I got one, in time, it was certainly an improvement over the AR-1,

BUT that path differences (proven by everybody and his brother at the time to be sonically undetectable) started to annoy me, but I DID like the low FM distortion and high power output. By 1970, when Richard Heyser, FINALLY was able to give his talks at the AES, we knew that we had to fix the path length differences. More later.

Please refer to those AR3 tweeters by their correct technical name. They were the "fried egg" tweeters :)

Of course they were an improvemnt over AR1 tweeters. AR1 use an 8" Altec or Western Electric driver as a tweeter. When AR1 was marketed, no signal from a commercially available source had output over 12khz. I got that from the Lansing Heritage website.

AR3's tweeter had relatively low and clearly inadequate output relative to the other drivers and it had a FR that fell with rising frequency. Of course it sounded dull, muted. Mellow is too generous a description for it unless its output was "equalized." That's how Allison pulled off the LvR demos as I mentioned in an earlier posting.

K-Horns went down the Altec harsh horn tweeter path. Unlike its me-too competitor JBL Hartsfield, they were made of cheap commercial drivers. These were the two schools of design, the mellow rolled off east coast sound and the harsh west coast sound. Within its power handling capabilities AR1 and its descendants beat the socks off K-horn in the lowest ocatve. K-horn cuts off sharply at 40 hz. AR1 is down 3db at 42 hz with an equalizable 12db/octave rolloff that can extend it at least an octave. AR1 has only 5% THD at 30 hz. That's why the NY Audio Leage (predecessor to AES) was able to pull of the LvR demo of AR1 against an Aolean Skinner pipe organ at Riverside Church with them. I'm not sure K-horn could produce anything but doubling driven at 30 hz.

I see you are leading us down the marketing gimmick du jour of the 1970s, time alignment/phase coherent speakers. The bad news is that it doesn't work. For the resultant fields for the tweeter and midrange or woofer to be phase coherent at any point in space they must not only be coherent in time but also coincident at their coordinate points of generation in space, at least insofar as dimensions comparable to the wavelengths they cross over at are concerned. So they would have to be coaxial and then the alignment would only hold on axis. Time aligned speakers don't meet that criteria, there will be interference patterns at all points in space due to the path length differences of two drivers at different points in space generating fields even vibrating at the same time. The good news is that there is no evidence that phase misalignment as is typical for all speakers is even audible. At worst they show up as FR reinforcements and cancellations at different points in space at different frequencies. That fad ran its course and died, you don't read it in ad copy much anymore.
 
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Its almost as if you Jan have a 'reality religion' in that you'll talk about 'reality' but never, ever put up evidence for it:p Gives me a chuckle every time...

Giggles apart, I'm calling you on it. Put up some evidence for this claimed 'reality' beyond people's perceptions.

Really? When you listen to stereo, is there really a singer in between the speakers? Is there really a source of sound straight in front of you?
The way we listen to stereo, there are two speakers, one left and right. Yet we clearly hear a singer, a piano, whatever, somewhere *between* those speakers. Sometimes we can even hear a height difference between two sound sources between or even outside of the speaker field.
Our minds are making this up for us; stereo is only possible thanks to the capability of our minds to hear things that aren't really there, and disregards the things (speakers) that *are* there.

Yet when doing sighted tests many strongly maintain that they are exactly hearing what's there, that there is NO chance that what they hear is manipulated by their brains. I find it amazing that people who think of themselves as intelligent, logical persons can maintain such a conflicting position without blinking ;)

jan didden
 
Really? When you listen to stereo, is there really a singer in between the speakers? Is there really a source of sound straight in front of you?

As you're using this word 'really' then its for you to explain what you mean by it. I'd just say I perceive (aurally) a sound source before me. If the system is a good one, the perception is more convincing. So go on, tell us what 'really' means in your idiolect.

The way we listen to stereo, there are two speakers, one left and right.

So you say. I'd say (for the purposes of this discussion where we're digging into the fine details) that you perceive visually a left and a right speaker. Both the speakers and indeed all of your visual field is the product of perception.

Yet we clearly hear a singer, a piano, whatever, somewhere *between* those speakers. Sometimes we can even hear a height difference between two sound sources between or even outside of the speaker field.

Yep, no worries - its rather system dependent, but I'm with you in principle.

Our minds are making this up for us; stereo is only possible thanks to the capability of our minds to hear things that aren't really there, and disregards the things (speakers) that *are* there.

Nope, the speakers that you see (being the product of visual perception) are also 'made up' by the capability of our minds (in this case, the visual cortex which is a major chunk of the processing ability of our brains). So it seems that 'really' here for you means 'correlated with at least one other perceptual modality'. Is that a fair translation of your use of the word?

Yet when doing sighted tests many strongly maintain that they are exactly hearing what's there, that there is NO chance that what they hear is manipulated by their brains. I find it amazing that people who think of themselves as intelligent, logical persons can maintain such a conflicting position without blinking ;)

But its all part and parcel of the human condition. Behavioural economics books are full of it :D What's amazing is that you, an educated and intelligent individual maintain a kind of Chinese wall between visual perception and auditory perception - apparently accepting that the latter is made up but not the former.
 
Difference is that it requires mind-altering substances to change the visual perception of the loudspeakers' location.

Alas, the sonic image that's perceived can be altered by the switch of a button.
Gathering from your photography hobby album you're old enough to have experienced the Bose treat in a '70s discotheque (before the turntable stops spinning and the regular lights go on).
 
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As you're using this word 'really' then its for you to explain what you mean by it. I'd just say I perceive (aurally) a sound source before me. If the system is a good one, the perception is more convincing. So go on, tell us what 'really' means in your idiolect.



So you say. I'd say (for the purposes of this discussion where we're digging into the fine details) that you perceive visually a left and a right speaker. Both the speakers and indeed all of your visual field is the product of perception.



Yep, no worries - its rather system dependent, but I'm with you in principle.



Nope, the speakers that you see (being the product of visual perception) are also 'made up' by the capability of our minds (in this case, the visual cortex which is a major chunk of the processing ability of our brains). So it seems that 'really' here for you means 'correlated with at least one other perceptual modality'. Is that a fair translation of your use of the word?



But its all part and parcel of the human condition. Behavioural economics books are full of it :D What's amazing is that you, an educated and intelligent individual maintain a kind of Chinese wall between visual perception and auditory perception - apparently accepting that the latter is made up but not the former.

I agree with all of this - indeed the visual perception is also a figment of our brains. I can agree with your translation of my use of 'real'.
And yes it's all part and parcel of our human condition. But accepting that, as I think you do, it still continues to amaze me that in the case of a sighted test, many appear to be convinced that their hearing does provide an accurate representation of reality even when they are confronted with clear evidence to the contrary whenever they listen to stereo.

For the record, I'm not saying that all subjective sighted test results to the audibility of something are wrong by definition. I'm only saying, based on the above, that we don't know, unless the test is in some way controlled to be sure its ONLY the audible component that is tested.

jan didden
 
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I agree with all of this - indeed the visual perception is also a figment of our brains. I can agree with your translation of my use of 'real'.

Cool. But then you go on to talk about 'hearing an accurate representation of reality' when you've agreed with me that what's 'real' is actually being made up. So we seem to have gone around in a circle and made no progress at all. Still you appeal to 'reality' when you seem to be agreeing that its all perception. Never mind, all good fun to debate :D

Yes, many do not realize the pervasiveness of the placebo effect in sighted testing, I'll grant you. But then again, that's because they do hear what they hear, so its no wonder.

If we were to translate the audio placebo effect into the medical field, ISTM that audio 'objectivists' are those who'd deny that a person's headache has really gone away when they take a placebo. According to the 'audio objectivist' position, people whose headaches have been cured by placebo are 'imagining' their cured condition. This I find rather a peculiar state of affairs, as medical scientists have no problem with placebos having a real effect. What's so different about audio?
 
If we were to translate the audio placebo effect into the medical field, ISTM that audio 'objectivists' are those who'd deny that a person's headache has really gone away when they take a placebo. According to the 'audio objectivist' position, people whose headaches have been cured by placebo are 'imagining' their cured condition. This I find rather a peculiar state of affairs...

It is indeed peculiar because it's wrong, incorrect, and a misrepresentation based on word games.

Try this one:

"Audio "objectivists" are those who would deny that the ingredients used in the placebo caused the person's headache to go away."

Of course, if you're someone selling expensive placebo ingredients with unsupported claims of efficacy, you don't want those nasty skeptics to queer the pitch.
 
It is indeed peculiar because it's wrong, incorrect, and a misrepresentation based on word games.

Evidence please that its based on 'word games' ?

Try this one:

"Audio "objectivists" are those who would deny that the ingredients used in the placebo caused the person's headache to go away."

Tried, found wanting. Surely if the ingredients of the placebo are sugar, there's nothing to deny. Its not even argued by 'subjectivists' that sugar makes headaches go away.
 
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