John Curl's Blowtorch preamplifier part II

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About mixing with headphones, if you make the headphone's balance for the studio's musicians with your monitors, you'll get a lot of complaints. The good practice is to use the same headphones than us, and mix their monitoring balances with it.
Suddenly, they will tell-you they have the best balance ever (They say that to all the girls :)
 
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Interesting discussion. I was involved in marketing an analog noise canceling chipset a few years ago. Although very good at the semiconductor part, the engineers had no feel for the complexities of the acoustic part of the system. Customers were trying to use us as an acoustic tuning service (we had a HATS and the measurement gear). Eventually I persuaded the people responsible to kill the project. Headphone design, and getting a reasonable response is very difficult - I must have seen dozens of plots and they never looked clean and smooth, and customers tweaked endlessly. A hopeless cause.

The little Sony, Panasonic etc IE's noise cancellers that you buy at the airports are remarkably good for the circa $70 you pay for them. Interestingly, designed and engineered in New Zealand of all places . . .
 
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Can-you describe this 'dummy head+ears' ? Molding of a real ear in silicon ? Then record of a flat loudspeaker in open ear to calibrate ?
(Excuse-me, Richard, i have no experience in headphone design, neither had read a lot about.)

The artificial ear is quite complex. Ear and Cheek Simulator Type 43AG

There are different silicone ears in different durometers for different purposes. Sony made molds of over 150 people to get a "reference" ear that would give repeatable measurements. Turns out it was the smallest one that worked best for them. The inner part, the 711 coupler (or one of its variations, IEC 60711, Zwislocki et.al.) are designed to mimic the acoustic impedance of a real ear. They have resonances tuned to match the standard (which I think was Zwislocki's wife originally). They are all useless above 7-8 KHz for anything real.

Fig 7 here http://www.grasinfo.dk/documents/pd_43AG_ver_10_september_2012.pdf shows the typical response curve of the coupler. If you correct for that you get really weird results (I tried it).

When you ask a headphone vendor to make their best headphone they always respond with "what curve do you want?" They really don't know what to make.

Waterfall plots don't really show much either, or if they do the device is a real disaster. Most of the transducers I have measured are really low distortion, .1% and less at normal hearing levels. The measurement equipment usually used is the limitation in the published measurements. However, that said, the materials have a major influence on the sound and I have not found a way to measure those effects. It seems easier to just tap and listen.

The parts are very small and complex so getting consistency unit to unit is quite difficult. It turns out not to be an easy way to make money.
 
AFIIK the Fenway "green monster" flap was a complete fabrication.

What Monster Cable did was oppose the Red Sox's trademark application for "Green Monster."

Monster's thug lawyers are ruthless, usually going after the little guys, like Snow Monsters, a skiing program for kids.

And remember "Monster Garage" on Discovery? Monster went after them too. Check out "Monster Garage" on TESS and see who owns the trademark for "Monster Garage" now.

These people are just plain evil. I'd love nothing more than to see Monster Cable just disappear and Noel Lee out begging on the streets.

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I know this is falling on deaf ears but just see how long you could offer a Coke power amp before the lawyers show up. Unfortunately trademark law puts you in a difficult position. I had a trademark stolen from me simply because I could not afford to defend it, regardless of my legitimate claim. The "system" is rigged for the rich guys.
 
I know this is falling on deaf ears but just see how long you could offer a Coke power amp before the lawyers show up. Unfortunately trademark law puts you in a difficult position. I had a trademark stolen from me simply because I could not afford to defend it, regardless of my legitimate claim. The "system" is rigged for the rich guys.

Ultimately it's rigged for the !@#$% lawyers.

Coke would have a case under "dilution," seeing as most everyone on the planet knows Coke, which makes it a "famous mark." Monster has used this same "dilution" theory in most all of their cases, though no court has ever ruled that "Monster" is a "famous mark" for Monster Cable. Nor would they ever likely receive such a ruling as there are a bazillion non-Monster Cable trademarks out there using the word "Monster."

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You did the vaguely described "experiments", so you're the one who has to answer that.
The 'experiment' has been conducted on several normal hi-fi systems, and consists of fitting ferrites to power and/or signal and/or speaker cables.
In each case I get the same sonic change when fitted with detachable ferrite 'inteference stoppers'...nasty highs, shouty mids, boomy bass.
Stuart, please enlighten me why this should be so....this is your quote "Where would you get that curious (and totally incorrect) idea?".

Thanks, Dan.
 
The 'experiment' has been conducted on several normal hi-fi systems, and consists of fitting ferrites to power and/or signal and/or speaker cables.
In each case I get the same sonic change when fitted with detachable ferrite 'inteference stoppers'...nasty highs, shouty mids, boomy bass.
Stuart, please enlighten me why this should be so....

Typically, when I run into a problem, I break out my multimeter, my scope, a spectrum analyzer, and a signal generator and start getting data. Without data, you're shooting in the dark, and I can't really do any better from 12,000 miles away.
 
I would love to see some real data regarding ferrites and audio, also ferrites are designed for different frequency ranges (generaly used to solve problems with quite narrow range of frequencies, and all in the MHz), and often used to stop equipement transmitting signals into the ether via them nasty cables.
Though if I remember rightly standard ferrites were canned by the audio press, but Audioquests RF stoppers were deemed OK (these cost about a zillion times the cost of standard ferrites).
If people near you are using power line communications then ferrites can help limit this mains borne EMC from entering your system.
As said I would like to see some empirical data on ferrites and audio, and for different types ad frequency range of ferrites, because I wonder whether this is another overrated problem like "skin effect" at audio frequencies...
 
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