John Curl's Blowtorch preamplifier part II

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Yes - not even whole words, often endings are missed off. It's exposed when one tries to read aloud from a written text one hasn't seen before, and get any sense of natural flow. Unless one is used to reading aloud, that is.

I was watching a newsreader quoting from an auto reader the other day, the words must come up in stages across lines as one word started of one way, then when he got the full word he had to repeat the first syllables with a change of pronunciation. They must get use to and better at reading autocues.
 
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I'll look into it, I tend to read pretty fast mainly due to constant reading, from an early age. Many cant understand me these days because I refuse to have modern mobile phone (I use mine for phone conversations and the occasional text) and I will read a book rather than watch TV, I don't use social media (apart from DIYAudio!) and I'd rather go out and look at the beauty of the world than mess about online.... Computers are for work and developing photos in my world...:)
:up:

A friend revealed to me that he still sounds out words when reading, a crippling habit he never overcame, despite managing a PhD. I stopped sending him much in the way of material (usually health-related, sometimes musical [his field], as he resents anything that questions his MD's prescriptions [in both senses of the word], and most anything takes a long time for him to read and digest).
 
Hi everyone,

Well, I'm back from the summer vacations in Greece. Despite what you might have surmised from TV news, Greece has NOT gone bakrupt and has NOT sunk into the sea. But it has been hit hard by mostly Western propagnda, and the tourst season has fallen well short of the usual. Even at the hieght of the toursits season, free place available almost everywhere (I went), but with a radical change of the guest structure. Almost no German nad Frencg reistration plates on roads and in Thessaloniki, now it's a lot of Swiss, Bulgarian, Romanian and Hungarian, plus of of course the usual multitude of Serbian registration plates. Unusually, a suprising number of Croatian plates, mostly from the city of Osijek. I say surprisingly, because the Croatian Adriatic sea coast always did beat the Greek coast for beauty hands down overall.

Attention wine lovers - the Greeks in the north of the country, in the Chalikidi littoral people say they had an excelelnt summer, just the right mix of rain and sunshine, so this year's wine vintage should be excellent. The available table grapes certainly seem to warrant the claim, better than usual, and the usual was a high standard, this year was positively delicious.

My usual first dinner at arrival which is by default accompanied by a bottle (0.7 litres) of chilled Imiglikos wine (local demi sec) makes if very clear why Zeus and the gang drank so much wine. I believe even the wise goddess Athena couldn't resist a few cups.
 
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My usual first dinner at arrival which is by default accompanied by a bottle (0.7 litres) of chilled Imiglikos wine (local demi sec) makes if very clear why Zeus and the gang drank so much wine. I believe even the wise goddess Athena couldn't resist a few cups.
They did dilute it a lot so they could drink for hours. I went to an interesting and scholarly lecture and subsequent wine tasting at the Getty a few years ago.
 
They did dilute it a lot so they could drink for hours. I went to an interesting and scholarly lecture and subsequent wine tasting at the Getty a few years ago.

You know Brad, locally and as far up northwards as Germany, people there are two subvarants to pure wine. One is called "gemischt", in German "mixed", which is half water, half wine, and a "spritzer", half wine half soda water, lately more often half wine, half mineral water with gas.

When a gang meets up in the local bar, and plans to stay for hours, they go for these varians so nobody passes out prematurely. Also popular as a chaser for local BBQ, a total national specialty. Ordering fish (sweetwater or sea) without wine is a local sacrelegde.
 
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You know Brad, locally and as far up northwards as Germany, people there are two subvarants to pure wine. One is called "gemischt", in German "mixed", which is half water, half wine, and a "spritzer", half wine half soda water, lately more often half wine, half mineral water with gas.

In Austria the heurigen serve "new" wine which is spontaneously fermented and sold the next day. It is only about the strength of beer, required with a schlachtplatte.
 
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For clarity, the propagation velocity is very different in each of those modes, of course. In cantilevers, only transverse flex propagation is slow enough to be interesting, and even that only at audioband hf.

Transverse waves in cantilevers, structures like beams, rods etc, is dispersive - that is to say velocity increases significantly with driven frequency. For a given rod like structure such as a cartridge cantilever, velocity scales with the 4th root of the ratio of flex rigidity to mass per length, and with the square root of frequency.

So both transverse velocity and dispersion depends on material properties, as well as the cross-section profile, and it's definitely not fair to say that metals aren't dispersive as far as transverse propagation is concerned. Real life evidence of this is transverse wave propagation in train rails, where we hear the high frequencies first for an approaching train.

Compression and surface waves aren't important in cantilevers, or more to the point the frequencies at which they become significant is way beyond the audioband. Not so transverse (flex) waves.


Lucky
I was surprised when i saw your TL cantilever model (*), Next I was even more surprised reading about the dispersion in your last post.
This clings 'guided waves testing' to me


Dispersion is not due to material inherent properties ( -almost- isotropic materials are -almost- non dispersive acoustically) but due to accumulated wave mode changes when relatively long waves interfere obliquely with structural geometry upon multiple passes (resonance) along a long solid structure.

The combination of long wavelength and small thickness is favorite for thinking that guided wave theory is applicable to a cartridge cantilever case.

Allow me to express my concerns over the validity of the application of this theory due to the minimal cantilever length when compared to excitation's wavelength.

I haven't the means to test or simulate the scenario. If you are in position to do so, please check what happens at such a small distance from the excitation point (single excitation point, not comb excitation)

In any case, thank you very much for the fresh look you provide on this old problem. That was a stimulus for me reading further on an interesting topic.

Speaking of cantilevers,
Beryllium cantilevers
Shure US4473897
Pioneer, 10 years before Shure
US3909008
US3961797


when we were talking about the bending waves in a loudspeaker cone!

Steven
When was that Steven? I think that cones is a good place for applying Lucky's knowledge.

Does this apply to thin-walled tubes in the same way?
Chris.
Under the constraints I mentioned and for a short tube, yes.
When the tube is butted or slotted, condition is more complicated. When the tube is long, Lucky's propositions fit well.

George
(*)Lucky, just a question. What propagation velocity did you chose for the cartridge cantilever TL sims?
 
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George that would have been at least a month or more ago. The argument was that some made the mistake to think that a cone acts as a real piston at lower frequencies greater than the cone diameter. I should have remembered the information in Martin Colloms High Performance Loudspeakers books. There are some very good sections on how a cone goes into breakup and that doesn't require the waves to be shorter than the diameter of the cone diameter. I've been talking about some of these things with kgrlee, Richard Lee, who has much more actual experience with much of this than anyone else I have ever talked to before. The information in M. Colloms book seems to have come from research that kgrlee had done earlier when he was at Celestron and KEF.
 
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