Wavebourn,
On your new optical mic experiment how does the size of the diaphragm relate to the frequency response curve? Will it select both the upper frequency corner frequency and the amplitude the same way that an acoustic mic works with just a different way to convert the signal?
I understand your liking of the concrete for your sub woofer in the floor, but have you ever had to deal with a concrete form that actually started to resonate at a select frequency? I have worked with both high density enclosures and also just the opposite with very low density but high stiffness and they both work when done correctly.
On your new optical mic experiment how does the size of the diaphragm relate to the frequency response curve? Will it select both the upper frequency corner frequency and the amplitude the same way that an acoustic mic works with just a different way to convert the signal?
I understand your liking of the concrete for your sub woofer in the floor, but have you ever had to deal with a concrete form that actually started to resonate at a select frequency? I have worked with both high density enclosures and also just the opposite with very low density but high stiffness and they both work when done correctly.
Pace Wave. I admit to playing the dick contest here. Guilty! More outrageous cos the only evidence is some recordings that no one here wants to listen to. Mea culpa, mea culpa, mea maxima culpa.
But I'm still interested in your
Your "nobody can do it" is of course a challenge to this pseudo guru.
How about you choose ONE of your optimisation criteria or maybe ONE type of mike for a practical application and tell us about it?
One thing I learned 25 years ago was that there is no such thing, and will never be, such a thing as a 'perfect' speaker. The only concept that makes sense is a "perfect" system, one that works well enough to fool the ear/brain. The gestalt is the only thing that matters, everything else is just fiddling around the edges, rearranging the deck chairs ...
I'm tired of listening to supposedly "correct" systems which just sound like sh!t, YAH ...
Frank
I have no data yet on that mikes, I am going to torture them in order to see what to expect from them.
Speaking about concrete, I made some experimental boxes of "shelf" - size. They looked ugly, but were dead like a grave: "stealth" - type shape, gravel of random sizes, uneven thickness of walls. Another kind of similar boxes I made with concrete and thin sand adding poly-vinyl-acetate; they look nice, but ring like bells. Something in the middle may be more optimal, but I gave up that experiments. Another material was, a composite inside of nice looking externally boxes. Most promising, if to find a composite that sticks better to the wall instead of gloves.
I would like to try Bakelite made with hemp fibers some day.
Speaking about concrete, I made some experimental boxes of "shelf" - size. They looked ugly, but were dead like a grave: "stealth" - type shape, gravel of random sizes, uneven thickness of walls. Another kind of similar boxes I made with concrete and thin sand adding poly-vinyl-acetate; they look nice, but ring like bells. Something in the middle may be more optimal, but I gave up that experiments. Another material was, a composite inside of nice looking externally boxes. Most promising, if to find a composite that sticks better to the wall instead of gloves.
I would like to try Bakelite made with hemp fibers some day.
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Injection or compression molding may be impractical, but composites using reactives (e.g., polyesters, phenolics, epoxies, siloxanes, urethanes...) are quite practical- you can build wood and wax molds. Lots of opportunities to play with fillers, constrained layers, reinforcements, and the like.
Don't worry, Richard, I'll get there ...!More outrageous cos the only evidence is some recordings that no one here wants to listen to. Mea culpa, mea culpa, mea maxima culpa.
The ol' story, life is what happens ... . At the moment my system is bugging me, it's long in the tooth, pretty fragile, and some itty bitty thing is misbehaving ...
Cheers,
Frank
Missed that, can-you provide the link once more, please ? I was interested, at a time, with the psycho acoustic researches about vertical localization with only two horizontal sources.
Nice efforts, Anatoliy ...They looked ugly, but were dead like a grave: "stealth" - type shape, gravel of random sizes, uneven thickness of walls. Another kind of similar boxes I made with concrete and thin sand adding poly-vinyl-acetate; they look nice, but ring like bells. Something in the middle may be more optimal, but I gave up that experiments. Another material was, a composite inside of nice looking externally boxes. Most promising, if to find a composite that sticks better to the wall instead of gloves.
I would like to try Bakelite made with hemp fibers some day.
I've concentrated on stabilising the structure of the speaker within the room, this has always paid big dividends for me; effectively creating a path for the vibrational energy that the carcase is subject to, to be dissipated harmlessly. In particular, this means I can wind up the volume without concerns of the sound falling apart, even with very cheap speakers ...
Frank
It's all in reflections from the floor. Horizontally facing microphones do it well. I would say, more than well because they don't filter reflections like ears and brain. No need in vertically oriented capsules, it is a hypo for marketing purposes.
Thank you Frank.
And I tried this concept with very cheap drivers made by Foster for Sony. With great success.
Attachments
the only evidence is some recordings that no one here wants to listen to.
Ambisonic Info | Contributed Audio has the links to some of my favourites. There are more complete descriptions at Ambisonic Surround Sound. Ambisonics, 5.1, audio recordings — Ambisonic Surround Sound. Ambisonics, 5.1, audio recordings eg Glazunov-Spanish-Dance — Ambisonic Surround Sound. Ambisonics, 5.1, audio recordings
If you listen to Aaron's recordings on a proper Periphonic (with height) system, you'll hear the orchestra is below you. That's cos the mike is above and behind the conductor. With VVMic or Harpex, you can tilt the mike down if this bothers you. Most people won't notice the difference in stereo or horizontal surround ... unless they've heard these recordings on a Periphonic system. They were made in some of the best and most studied concert halls in the US and involve some of the world's top musicians. IM very HO, these are also some of the best orchestral recordings ever made.
BTW, in case it isn't clear, these recordings were made with a single, if rather, special mike.
I won't risk more of Wave's scorn but it turns out that to sample (record) a horizontal soundfield properly, you need to have capsules pointing up & down too. This is the basis of Michael Gerzon & Peter Craven's soundfield patent. eg a Mk4 is more omni-directional than a 1/2" B&K measurement mike. This is due to practical limitations, physics etc.
I was talking about a very scientific study from Ircam (France). They had designed a virtual localization processor. It was possible, listening through headphones (where are the reflexions ?) or 2 loudspeakers to move a mono sound in center from front to back of your head, and from down to up. It was based on group delais and response curve modifications.
Very impressive.
Reason why i'm interested in what can produce a multi axes recording...
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On the record! Reflections from the floor are recorded and reproduced. And if the system reproduces everything nice you have cues about the height. Even on mono. I would say, especially on mono listening through headphones. You even hear if the floor is wooden, concrete, or grass on a soil.
If time delay of a single syn-phase reflection is more than 6 milliseconds is seems above the head, if below 5 millisecond it seems below the head.
But the main problem is to record and reproduce reflections from walls, no matter how many capsules you use. It is fine if speakers reproduce direct sounds. But they reproduce reverberation from places when they are! I.e. they capture what had been bounced from walls to the point where capsules are, then speakers reproduce this mix from several points around you. Actually, as many mixes as many speakers you have. And then all this mixes bouncing from walls in the listening room screw the brain that gets confused hearing as if reverberation from the point of a big hall bouncing in the small room. That's why dipoles and open baffle speakers are loved by people, because they blend together reverberation in the room with reproduced reverberation. The brain goes more confused and does not hear mixes from the bigger room bouncing inside of the small one, and relaxes assuming that it all happens in a bigger room with some strange addition of the small one that it can happily ignore.
I realize, now, how they were stupid, at IRCAM to have spend so many years of study and measurements to understand acoustic environments and how ears + brain localize, specially front and back, while it was so simple to do-it with a single delay... or just in asking-you !
Thank you for your teaching, master.
For others who still have scientific curiosity: http://forumnet.ircam.fr/692.html
http://www.ircam.fr/50.html
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You are welcome, apprentice!
Some people get grants and study things that were known for ages searching for own unique explanations in order to get patents, or just to satisfy own curiosity for others' money. It is common in pharmaceutical industry when people spend thousands of men-hours to find some formula that works like herbal remedy worked since the beginning of the humanity, that differs from what can be found in the nature, in order to patent it, manufacture, and sell.
Nothing is new under the moon.
Oh dear, this reminds of a ferocious tussle in another forum, that I got involved in, that went on for page after page, day after day, about whether vertical height information could be effectively captured through normal mic's and then reproduced via conventional stereo speakers. Back and forth it went ... got hotter and hotter, but in the end (yeaahhh!!) the believers won, the other lot conked out ...
Wavebourn, I hope this one peters out faster ...
Frank
Wavebourn, I hope this one peters out faster ...
Frank
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