The main reason I like carbon fiber is that it's easier to sand
You get a finish that's as smooth as bondo, with a part that's stronger than glass.
Too bad it's so darn expensive.
If you sand make absolutely sure not to breath in the dust. Wearing proper protection is a must. Otherwise these fine fibers WILL imbed themselves in your lungs and cause mesothelioma
The price is high because the US military is using up something like 80-90% of the global supply.
Yes, you can sledgehammer my waveguides - not because the materials are so strong, but because they are massive, 1 -> 3 inches in thickness depending on where along the device.
A fiberglass horn is no where near as strong unless it is back filled with a composite material. But if you are going to do that then why bother with the fiberglass skin at all? Just cast it all in one step. That's what I learned from my fiberglass experience.
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When my cabinets were fiberglass skins they were back filled with rigid foam. Made a nice surface, and solid structure, but the labor was excessive and expensive and in the end results no better than what I make today in a fraction of the work. Materials cost more however, but in the US minimum labor is essential.
Yeah it kinda freaks me out that it feels like I smoked a pack of cigarettes for about a day after I work with CF. I find that using my angle grinder is even worse, ten minutes of that makes you feel like you spent all night in a smoky nightclub.
On a side note, that was an odd idea I had for the Gedlee speakers. If you could find a lawyer that could make a case that the Gedlee speakers were easier on the ears, it might be a justification for a nightclub or bar to buy them. Here's what I mean by this:
I've worked for big giant corporations most of my life, my current employer has 280,000 employees. And in places like this, there are TONS of little things that are done in the office to accommodate employees:
1) special keyboards to reduce workplace injuries
2) incentives to stay healthy
3) accommodations for various handicaps, such as special desks, input devices, etc
So if a big employer has any type of history of employees suing because they developed tinnitus due to the noise level in the workplace, then a speaker like what Geddes sells might be marketed as a way to combat those lawsuits. And lets be honest here, corporation don't just accommodate special needs because it's the right thing to do, they also do it because it makes business sense. IE, no employer wants to see people get hurt on the job, it's bad business. And there are lots of workplaces that could exacerbate tinnitus. (Night clubs, bars, restaurants, gyms. Heck, the office at my apartment complex plays it's music at over 100dB, for some unknown reason. Everytime I go in there I want to run out screaming!)
Tinnitus is caused by average level being too high, especially in the 4000 Hz range.
The way to combat lawsuits is to hand out hearing protection.
Play music like Nickleback, Motorhead, or Skrillex and people will get tinnitus regardless of whether the speakers lack HOMs or other distortion, when distortion is built in to the music a clean speaker won't save anybody's ears
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Tinnitus is caused by average level being too high, especially in the 4000 Hz range.
The way to combat lawsuits is to hand out hearing protection.
Play music like Nickleback, Motorhead, or Skrillex and people will get tinnitus regardless of whether the speakers lack HOMs or other distortion, when distortion is built in to the music a clean speaker won't save anybody's ears
Where's the profit in that?
The last place I did technical consulting had the whole office decked out with these:
Edison Electric Table - ELE-TB | VersaTables.com
Cuz, ya know, people *need* $1000 motorized desktops. Plus $1000 chairs. The companies market cap has gone up $2,400,000,000 this year, or about 2.4 million per employee, so they have some money to burn on desks
Art - I don't think that there is a single cause of tinnitus and I don't even think that it is even well established what all the causes are.
It can be induced - high dosages of aspirin - this means that there is a neurological aspect to it.
I have heard that one can get beats with tinnitus tones from external tones! That makes it partly physical as well.
As I understand it, it is a complex subject that is not well understood.
It can be induced - high dosages of aspirin - this means that there is a neurological aspect to it.
I have heard that one can get beats with tinnitus tones from external tones! That makes it partly physical as well.
As I understand it, it is a complex subject that is not well understood.
Workplace health
Should probably stick with horns, waveguides, and loudspeakers. Given the amount of noise pollution in factories, WalMart, thump-mobiles,etc.... never gonna pass 1st base wrt enforcing safety in pursuits of pleasure in bars, restaurants, etc... concerning sound quality from a health perspective!!
Having engineered and been safety officer in the chemical industry for... ohh 50+ years, from FWPCA to EPA to aerospace to DARPA to high-tech semiconductor fabrication, and 20+ yrs. in medicine... trust me... stick to physics and stereo
We used to joke about the ubiquitous BOSE 901 speakers (or Altec VOT's, etc.) in bars and the brown cigarette tar stains on the grill cloths where the speakers pumped... extracting the carcinogens and then correlation back to average exposures to bar/restaurant patrons and employees from 2nd hand smoke, etc... and interdiction in kind...
John L.
Never had the time or resources to pursue it though...
Where's the profit in that?
The last place I did technical consulting had the whole office decked out with these:
Edison Electric Table - ELE-TB | VersaTables.com
Cuz, ya know, people *need* $1000 motorized desktops. Plus $1000 chairs. The companies market cap has gone up $2,400,000,000 this year, or about 2.4 million per employee, so they have some money to burn on desks
Should probably stick with horns, waveguides, and loudspeakers. Given the amount of noise pollution in factories, WalMart, thump-mobiles,etc.... never gonna pass 1st base wrt enforcing safety in pursuits of pleasure in bars, restaurants, etc... concerning sound quality from a health perspective!!
Having engineered and been safety officer in the chemical industry for... ohh 50+ years, from FWPCA to EPA to aerospace to DARPA to high-tech semiconductor fabrication, and 20+ yrs. in medicine... trust me... stick to physics and stereo
We used to joke about the ubiquitous BOSE 901 speakers (or Altec VOT's, etc.) in bars and the brown cigarette tar stains on the grill cloths where the speakers pumped... extracting the carcinogens and then correlation back to average exposures to bar/restaurant patrons and employees from 2nd hand smoke, etc... and interdiction in kind...
John L.
Never had the time or resources to pursue it though...
The stock market has come up a couple times in this thread - and that raises an interesting idea -
Dr Geddes have you ever considered becoming a quant?
The scientific rigor that you apply to soundwaves has quite a bit of correlation to options pricing. And though I do not work on Wall Street, I get the impression that many of the trading desks are at a stage of development where they're still trying new things and they value new ideas.
It's a really fun problem to work on too! Options pricing is hideously complex. A couple of years back I tried to write a program which would basically create a 'metric' for stock value, in which you could plug in various inputs, and quickly discovered that it's a real Big Data problem due to the sheer volume of stock prices. (IE, do you look at a years worth of data? Ten years? And in that timeframe, how granular do you get?)
A quote from one of the quant papers, which has some 'echoes' of waveguide theory:
"First, option prices are converted to implied volatilities to obtain the implied
volatility surface. Then, an interpolant is Ötted to the IVS, typically a cubic
spline or a low-order polynomial. Finally, the implied volatilities are converted
back to option prices. Therefore, the e§ectiveness of the implied volatility surface as an interpolation tool can be assessed by measuring the option pricing error of the IVS."*
And some evidence that your resume is right up their alley:
"I have a Ph.D. in math.
Stochastic calculus and brownian motion is used (implicitly or explicitly) pretty much every day.
Yes, if you are capable of getting a physics bachelors degree (at a rigorous department) and are reasonably motivated, then you can learn a lot of stochastic calculus on your own. Let me think a little about the book and get back to you. Remind me if I forget.
I've most often used C/C++ and VBA. I know that C# is also used frequently, as well as R (at least among the more statistically-driven roles)." (From a reddit "ask me anything"**, where readers were asking what type of background is ideal for quants.)
* https://editorialexpress.com/cgi-bin/conference/download.cgi?db_name=CEF2013&paper_id=103
** IAMA Wall Street Quant. AMAA. : IAmA
Hmmm.. I was about to say that's not right, but then I thought about it for a minute... If the beating is formed physically, it must physically exist as waves in the cochlea, right? Then different neurons respond to not just the two frequencies, but also the beat frequency. If it was all neurons, how would the third frequency get in there? Then again, maybe perceiving the two tones without the beating would be like seeing something as solid red and solid green at the same without any blending or switching, i.e. the brain is "correcting" the sensory input at a low level. This is probably one of those things somebody already tested.
Reflex contractions of the middle ear muscles appear to be involved with your tinitus . Linked reference describe lag in reflex on order of 10ms. When I do testing with broadband bursts of short duration, I am aware of physical sensation in my ears, and of brief dampening and timbrel change to sound reflecting about in room.
Ears are know to emit sound as well, measurements are often used in helping determine custom equalization done with many hearing aides.
I've got tinnitus with intensity modulated by jaw tension. Clenching jaw causes ringing sounds in both ears to increase. Shifting jaw to right increases ringing sound in left ear, and corresponding shift of increase in ringing in right ear with jaw shift to the left.
Ears are know to emit sound as well, measurements are often used in helping determine custom equalization done with many hearing aides.
I've got tinnitus with intensity modulated by jaw tension. Clenching jaw causes ringing sounds in both ears to increase. Shifting jaw to right increases ringing sound in left ear, and corresponding shift of increase in ringing in right ear with jaw shift to the left.
Tinnitus is readily perceived as continuous yet often indeterminate high frequency sounds. As youthful person I could readily hear sounds from television flyback circuits, and my tinnitus is reminiscent of this.
High levels of caffeine and nicotine seem to exacerbate perception.
Blood flow sounds are very different.
High levels of caffeine and nicotine seem to exacerbate perception.
Blood flow sounds are very different.
Back in 1995 or 96 I was contacted by a guy who ran stock trading company. He was offering me a job. I did not understand how he wanted to use me at that time so I declined - I just couldn't see how I could be effective. Now days I read a lot about trading and I have read some high level books and papers on the mathematics of economics. The math gets quite complex, right up my alley and I see exactly how that guy wanted to use me.
But after 2008, the market for quants has all but gone away. Their heyday was in the early 2000's doing options pricing etc. Had I taken the job in the 90's I may well have gotten rich! But hey, there is no looking back.
There is a good book by a theoretical physicist about becoming a quant called "Models Behaving Badly". Its a very good look inside the job and its not quite as glowing as it seems, although I did get the idea that this guy got very rich.
Fictitious vehicles for quants
A couple of articles from Rolling Stone re: quants, etc.
The Last Mystery of the Financial Crisis | Politics News | Rolling Stone
The Great American Bubble Machine | Politics News | Rolling Stone
When Moodys and Standard and Poors are selling quality ratings to the highest bidder, and SIV's, CDO's, derivatized tranche's of who knows what are being leveraged to the hilt, doesn't matter how good a mathematician is... garbage in, garbage out still reigns supreme.. AKA, pump and dump
and if you don't think it's happening today... think again
John L
A couple of articles from Rolling Stone re: quants, etc.
The Last Mystery of the Financial Crisis | Politics News | Rolling Stone
The Great American Bubble Machine | Politics News | Rolling Stone
When Moodys and Standard and Poors are selling quality ratings to the highest bidder, and SIV's, CDO's, derivatized tranche's of who knows what are being leveraged to the hilt, doesn't matter how good a mathematician is... garbage in, garbage out still reigns supreme.. AKA, pump and dump
and if you don't think it's happening today... think again
John L
