John Curl's Blowtorch preamplifier part II

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I thought Christian Doppler described it in 1842.

Right, but for moving with speed sources, not for oscillating cones that is the different matter.

I read recently a paper from some respected speaker manufacturing company regarding line arrays in which they view waves in the air the same as waves on surface of water claiming the same interference patterns... What is gross misunderstanding between properties of gases and liquids! I wish they would fill their horns with water and measure then..
 
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If you set one of those sources up horizontally and took a microphone happy at >165 dB, one sees the wave shape is a sine wave but as you move say 6 inches away it is changing, a foot away and it is a saw tooth shape, not a sine wave.

Tom Danley

Keith Johnson used this effect (different speeds of compression and rarefaction) to explain to me why absolute phase is important. The waveform from a horn (Trumpet) changes significantly with distance. I'm not sure what to make of the knowledge.

Nelson Pass has opinions about the effect of compression/expansion of the two halves of the waveform in an amp and the associated sound.
 
It is almost impossible to 'pre-distort' properly. There was the same problem with pre-distorting analog tape recorders to remove 3'rd harmonic distortion.


the problem has been addressed, "solved" to the extent of making at least voice quality audio appear out of thin air from ultrasonic nonlinear mixing in the air

several times in fact in the 1990's Sound from ultrasound - Wikipedia, the free encyclopedia

you can buy them: Audio Spotlight - Add sound and preserve the quiet.

lots more at AES, Czerwinski is one researcher on air nonlinearity distortion in normal audio band transducers at Rock Concert speaker array levels: AES E-Library Propagation Distortion in Sound Systems: Can We Avoid It?
 
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Keith Johnson used this effect (different speeds of compression and rarefaction) to explain to me why absolute phase is important.

Reminds me to point out here that much of the polarity affects/absolute phase are due to the fact that the ear mech is not symmetrical concerning pressure. It is more sensitive to 'suck out' or neg pressure than positive pressure. Thx-RNM

The implications on hearing certain asymmetrical waveform shapes and the polarity of harmonics created by non-linearities - not just magnitude- perhaps, needs more finely tuned consideration and appreciation?
 
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That's why I have 4-15 high effec. bass drivers and adding 2-18" subs with high power amps on all 6. To attempt some reasonable simulance of realism... realism with low distortion and no compression on my end of things.
Mr. Marsh, do you have a list of recordings where this is essential for your musical enjoyment? I'm not knocking your system, but I am interested in your answer.
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Its quite surprising that hardly anyone has conducted listening tests on speaker distortions since Peter. The pseudo prophet Floyd pretended to.

There are two questions you ask in such tests. The first is "Is it audible? When you have a "yes" to this, you ask the second, "Is it objectionable?"

When you do this properly, you very quickly realise where you need to improve speakers and where you can ignore the Golden Pinnae pundits and false prophets ..

.. that's assuming you are interested in better, more accurate sounding speakers.
 
There are two questions you ask in such tests. The first is "Is it audible? When you have a "yes" to this, you ask the second, "Is it objectionable?"

This questions are obsolete, in terms of high end sound reproduction. The right question is, "does it fool imagination as if it sounds real"? If it sounds like nice speakers, it is already objectionable and requires further R/D work.
 
This questions are obsolete, in terms of high end sound reproduction. The right question is, "does it fool imagination as if it sounds real"? If it sounds like nice speakers, it is already objectionable and requires further R/D work.
Some of my listening panel, the recording engineers and microphone designers who make their own recordings, would object if you accused them of liking only 'nice' speakers.

But if you must know, the speakers considered most 'accurate', 'real' bla bla by those who have some expertise on the matter, the recording engineers, mike designers, musicians and audience from the event ... are also the ones 'liked' by the general public. That's from Blind Listening Tests of course.

Golden Pinnae are more difficult to pin down as their 'likes', 'real' bla bla in Blind Listening Tests are usually (??) much less consistent than the general public. They often have completely opposite opinions on a speaker in a repeat test.

Nasty people might claim the Golden Pinnae are deaf.

But to get back on topic, some (??) of the distortions discussed here are well down the list in terms of audibility & relative nastiness. There are far more important distortions in speakers that need to be addressed if you want to fool the imagination.

Again I refer you to Peter's papers.
 
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Some of my listening panel, the recording engineers and microphone designers who make their own recordings, would object if you accused them of liking only 'nice' speakers.

But if you must know, the speakers considered most 'accurate', 'real' bla bla by those who have some expertise on the matter, the recording engineers, mike designers, musicians and audience from the event ... are also the ones 'liked' by the general public. That's from Blind Listening Tests of course.

Golden Pinnae are more difficult to pin down as their 'likes', 'real' bla bla in Blind Listening Tests are usually (??) much less consistent than the general public. They often have completely opposite opinions on a speaker in a repeat test.

Nasty people might claim the Golden Pinnae are deaf.

But to get back on topic, some (??) of the distortions discussed here are well down the list in terms of audibility & relative nastiness. There are far more important distortions in speakers that need to be addressed if you want to fool the imagination.

Again I refer you to Peter's papers.

Can you summarize please in short what did you say? How is it related to my remark?
 
Reminds me to point out here that much of the polarity affects/absolute phase are due to the fact that the ear mech is not symmetrical concerning pressure. It is more sensitive to 'suck out' or neg pressure than positive pressure.
He he, i had added an "absolute" phase reverse button on my preamp. Had no real explanation on this phenomena, obvious on kick drums. Thought it was loudspeaker side, thanks for the light.
Right, but for moving with speed sources, not for oscillating cones that is the different matter.
When a large band loudspeaker run a very low frequency (under 16hz) at large excursion, i believe it modulate in frequency a medium tone. An awful experience easy to reproduce, just useless because we can do nothing against it :)
Again, i ask myself how we can enjoy loudspeakers, ... still a big mystery for me.
 
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Golden Pinnae

I sat through the presentation at AES on listener preference on headphones. The daunting task of blind a-b's of headphones would put me off of ever wanting to try it. In any case, after watching the presentation I realized that there is a critical difference between making the sound most preferred in blind listening and the sound that will move the headphones off the retailer shelves and into consumers hands. Its the same issue that exists selling TV's. The brightest TV sells the fastest. No amount of education about ISF and color perfection will overcome that reality. The same for the uber-real sound that has become more common in consumer products.

Golden Pinnae unfortunately, except in ultra high end, are not a road to commercial success. Neither are blind consumer preferences. Certainly not like big bass and in your face presence.

Maybe we need to add a switch to audio systems that does what the TV's do; "torch mode" to sell them and "ISF" mode to listen to them.
 
And why blind ? Are-we lying to ourselves ?

are you sure you are a audio pro?? - believing stereo is "realistic" requires the audio illusion of "phantom position" for just one to start

being human means our brain lies to our conscious all the time

we really aren't very "self aware" when it comes to being able to audit how much our own sensory input is filtered, censored, patched up, overwritten on the way to conscious perception
 
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are you sure you are a audio pro??
No. But i tried hard to make believe-it to my clients.
being human means our brain lies to our conscious all the time
we really aren't very "self aware" when it comes to being able to audit how much our own sensory input is filtered, censored, patched up, overwritten on the way to conscious perception
Yes, but that the law at west of the Pecos. I mean, it is only after weeks of work with a set of monitors that i'm able to decide if it makes a "magic room". Looking at them change nothing :)
I'm very suspicious about the accuracy of my listening.
 
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I find it remarkable that people still feel that speakers are the key determinants of SQ; it's all about overall system tune. A $20 speaker driven properly will demolish a $20,000 one driven badly, from the point of view of creating sound that one wants to keep listening to. I've listened to enough uber-expensive, unter-performing loudspeakers hooked up to bling infested paraphenalia to last many lifetimes ...

It's all about getting "big" sound, people who can do this in a straightforward manner know how dramatically different this is from normal hifi, no blind testing or anything else is needed to establish the presence of this quality -- blind Freddie gets it, knows he's on a winner, straightaway ...

Frank
 
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