John Curl's Blowtorch preamplifier part II

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Trivial explanations like 'oscillation' or change in capacitance are pointless. We know how to check for these things, we also know how to protect an audio product from being sensitive to small changes like capacitance. It is called 'engineering'. '-)
Presumably this is another test you are
  • quite willing to pontificate about
  • but less eager to actually carry out
  • and if actually carried out on your product, the results are never to be divulged
In my very limited experience, this is called 'liquid BS from marketing'. Do you equate that with 'engineering'?
 
Presumably this is another test you are
  • quite willing to pontificate about
  • but less eager to actually carry out
  • and if actually carried out on your product, the results are never to be divulged
In my very limited experience, this is called 'liquid BS from marketing'. Do you equate that with 'engineering'?

Do you have a record of your boom beach? You were talking about it so many times, it persists in my I want to hear it. It can be very relaxing. I suppose, being a beach boom, you imagination, But of course I hear the one from my own memory. Either soft warm and loving black sea, or cold pacific ocean. Different sounds, different temperatires... Different CHANGES of everything...
They sound different, of course. You can afford several electret capsules.

..but can you record drops on your head, caused by an ocean wave?

It is what Wavebourn is all about... Waves on the ocean. drops on your forehead... Equally reproduced... Miracle, but it works if you know what to preserve, and how to preserve.
 
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jneutron;3264730 [B said:
As an aside, for a coax, there is no contribution of inductance for the outer shield anyway. The inductance of the coax is a direct function of the spacing between inner conductor and outer shield. Two wires at 90 degrees cannot cancel magnetic fields, the fields will add as a vector. That is why I am confused.[/B]

jn

And, for lowering capacitance, have you looked at the driven-shield technique??
 
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Christophe,
Yes that looks like the shielded cable that I have to run Cat6 over the roof of my house with a FM radio station within 100 meters blasting me with 50kw of power. How is that any different from the multiple pair foil wrapped snakes that we use on a stage for microphone connecting back to the board? Isn't this the same type of construction will just fewer pairs.

Esoteric to me means something out of the ordinary, something that not many know of or understand. Astrophysics would be considered esoteric by the majority of people in the world.
 
He didn't say that, and he hasn't. John refers to some published research which suggested audibility of 10us delays in localization. His area of expertise and accomplishment is running extremely high currents down wires, and trust me, he DOES know what he's talking about.
Thanks for this SY & Neutron.

I was rather hoping for new work to compare against my own miserable efforts. This millenium, I had a chance to skim through Blauert in one of my rare excursions into the civilised world. I was pleased to find not only loadsa new work, but also nothing which contradicted my stuff. :D

I shan't join in as my knowledge & experience is previous century. But for some very careful REAL life results on cable transients and matching, have a look at Pro Audio Design Forum • View topic - Balanced Outputs

IMHO, this is the worse case for cable effects if you discount gear that doesn't pass simple tests like Hirata, Quan etc. You can decide for yourself whether they will affect your Blowtorch.

Sorry I can't find anything reliable for speaker cables except for Fryer/Lee AES paper.
 
Do you have a record of your boom beach? You were talking about it so many times, it persists in my I want to hear it. It can be very relaxing. I suppose, being a beach boom, you imagination, But of course I hear the one from my own memory. Either soft warm and loving black sea, or cold pacific ocean. Different sounds, different temperatires... Different CHANGES of everything...
They sound different, of course. You can afford several electret capsules.
Wave, I'm not sure what my beach has to do with pseudo pontificators who refuse to release the results of tests they claim important, on their own products, simply cos these tests show their $zillion stuff sounds worse than cheapo 4558 stuff.

I can't afford to buy stuff but the wonders of the internet means since 2005 [*], I've posed as a guru on speakers, mikes, LN electronics & DSP. Some people have built stuff & used algorithms which I proposed ... and no one has figured out I'm a fraud yet. :D

But I cannot recommend you do this without careful research as there are a lot of fakirs eager to sell you bad sounding $zillion stuff.

It's a bit difficult for me to record the beach as the nearest power is some km. away and I don't have a good portable recorder with 4 x P48V mike inputs. I hope this pic will suffice for now. It isn't always as nice as this cos crocodiles. I often see sharks, turtles & stingrays. About 30min walk from my hut.


[*] Internet arrives in Cooktown at 28kB
 

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This millenium, I had a chance to skim through Blauert in one of my rare excursions into the civilised world. I was pleased to find not only loadsa new work, but also nothing which contradicted my stuff. :D
Blauert is always a good read.

It's interesting the research and how it never seems to hit the stereo reproduction nail on the head. Lots of interesting stimuli, like SAM pulses and such, but when I was searching for info on differential ITD, IID, and uncertainty regions vs distance and angle, nuttin. Greisinger's work seems to be the closest, but of course his research is directed.

Sorry I can't find anything reliable for speaker cables except for Fryer/Lee AES paper.
Yah, I've found little as well.

Guess I'll have to make some non inductive CVR's to do some tests. 1, 2, 5, 10, 20, 50, 100, and 200 ohms seems the most logical set. Gonna need a pair of IA's capable of isolating the amp end from the load end so scope ground currents don't spoil the measurement.

Digikey, here I come..

jn
 
I've got enough reward miles for a one way ticket. :D
You are most welcome to sleep on my floor Mr. Wurcer. No beds in my hut. I'll rustle up some road kill roo.

May I ask you to bring a bottle? Burgundy would be nice but it doesn't have to be 1st Cru. In fact anything that's nice to drink.

But beware, you may never leave. I didn't plan to become a beach bum. Seeing a shark, turtle & stingrays on my first visit to the beach was what swayed me. Hardly anyone goes there cos you can't drive to it.
 
It's interesting the research and how it never seems to hit the stereo reproduction nail on the head. Lots of interesting stimuli, like SAM pulses and such, but when I was searching for info on differential ITD, IID, and uncertainty regions vs distance and angle, nuttin.
The best summary is Gerzon General Metatheory of Auditory Localisation His treatment is mathematical but this paper repays close & repeated study. Many insights into when stereo works and when it does not.

Essentially there are only 4 localisation mechanisms. All others can be subsumed into these.
  1. LF 'phase' or ITD applicable when the wavelength is greater than the size of the Mk1HH. This is in fact the only cue that stereo addresses properly.
  2. ILD used when 'phase' starts to cycle above about 700Hz but applicable below that when phase is ambiguous too. Stereo sorta tries but often doesn't do a very good job.
  3. HF ITD. Impulsive or envelope delay
  4. Pinnae and other colouration
There are fixed head and moving head versions for each. Also the Mk1 Human Head is able to substitute some mechanisms for those which give confusing results. And there are overlaps especially for artificially 'panned' sources

The majority of theories are either [1] or [2]. (see General Meta for long but still incomplete lists) Gerzon provides tractable mathematical form for ALL these in his Velocty & Energy models; quite a surprising result if you look at the maths in some of the papers.

His hypothesis, which I share, is that the best systems, those which give the most convincing and satisfying localisation, satisfy many of these models simultaneously. We hear this as 'natural'.

If one cue is very strong but conflicts with the other cues, we might hear 'precise' localisation but also experience fatigue. This was the case with several of the failed Quad surround systems. You can't claim any particular mechanism is dominant even at a single frequency. You need to try and get all of them right or at least believable.

You'll excuse me if I don't join in the argument over delays in cables.
 
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His hypothesis, which I share, is that the best systems, those which give the most convincing and satisfying localisation, satisfy many of these models simultaneously. We hear this as 'natural'.
Richard, my fetish is, obviously, that low distortion of the signal at the point when it is fed to the speaker driver is key, in your wide readings have you come across anyone who's investigated this particular angle, to any degree?

Frank
 
Richard, my fetish is, obviously, that low distortion of the signal at the point when it is fed to the speaker driver is key, in your wide readings have you come across anyone who's investigated this particular angle, to any degree?
I'm not the right person to ask this. Because of ACE bass and my own Powered Integrated Super Sub tech, I tend to look at amp & speaker as one. The amp is just a crossover component to me.

One could consider the fancy ACE, current drive etc techniques as pre-distorting the signal so the final sound at the ear has less distortion.

I've also done too many Blind Listening Test where the speaker with more measured distortion has been reliably described as sounding 'undistorted' by some of the best ears in the business. Some of this is explained by our work on speaker distortions but not all.

I should add that most conventional speakers are designed assuming that what's fed to the speaker terminals is low distortion so this is definitely a worthwhile goal.

What's fed to the units is more difficult. eg If you change the treble capacitors for better ones, you will hear a difference. But this might simply be cos there is less loss so the treble is slightly louder. The fair comparison is to reduce the treble level so it matches the original. [*] Even using a new crossover PCB to say, facilitate bi-amping, changes the sound. (usually only seen at Delayed Resonance, (waterfall) level but you can hear it) It may be better, it might be worse. But it is almost certainly not what the original designer intended. (assuming he's competent and listens to his own designs)

But where I certainly agree with you is that it pays to be meticulous with everything even if the components are inexpensive. My own criteria for whether someone is really concerned about good sound is not the price tag on his gear ... but where he places his speakers.


[*] Yes. This is worthwhile doing with most inexpensive speakers with electrolytics in the treble xover. But there are good & bad electrolytics too.
 
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