Thank you kgrlee for commenting
Ni has to be a special case indeed.
As for more plastic diaphragms, please check pages 2-15, 2-16
http://www.bksv.com/doc/be1447.pdf
Correct. With the vent open.
Look at Fig. 2.6 to 2.9 of the above link.
Also Fig. 2.25 of this :
http://www.bksv.com/doc/be1373.pdf
Scott
If you are still interested on mics for infrasonics have a look on this (page 5 and on) Extreme Low Frequency Acoustic Measurement System
George
There is a problem that there is a multitude of free software that does the same stuff.
The GE Novasensor pressure guages work just fine for me. DC to about 3.5kHz. Not too expensive either.
Using a Laser on a reflecting surface as a microphone is common today among the spook (intelligence) trade. Measuring the density of air to make a microphone is something Audio Technica is doing (they presented some work on ion microphones but it seemed more relevant to ion speakers.) In the late 60's I read about using a small radioisotope and a sensor to measure the air density and turn it into audio. As usual it vanished since it didn't turn into money.
The optical system seems very close to this: Fiber Optic Measurement Systems: Non-contact Measurement Sensors, Solutions and Systems - MTI Instruments which is technically simple and straightforward if you make a diaphragm (I have used one to analyze a speaker) and it works well.
B&K make an RF version of the microphone preamp that could easily have response to DC. Sennheiser has a similar technology.
A small diaphragm will have a noise problem, it can not sense as much of the pressure wave so its output will be lower than a large diaphragm.
I saw a new mike at AES that uses what appears to be 4 1'X1.5" condenser mikes in an array. Lousy hf performance but good sensitivity and that large diaphragm sound.
The optical system seems very close to this: Fiber Optic Measurement Systems: Non-contact Measurement Sensors, Solutions and Systems - MTI Instruments which is technically simple and straightforward if you make a diaphragm (I have used one to analyze a speaker) and it works well.
B&K make an RF version of the microphone preamp that could easily have response to DC. Sennheiser has a similar technology.
A small diaphragm will have a noise problem, it can not sense as much of the pressure wave so its output will be lower than a large diaphragm.
I saw a new mike at AES that uses what appears to be 4 1'X1.5" condenser mikes in an array. Lousy hf performance but good sensitivity and that large diaphragm sound.
I think you'll find all the serious B&K measurement mikes use Ni. but ..
Caught out!
You are perfectly right George.But if you have access to a diving recompression chamber, you might want to try this with a Panasonic WM61a mike. There are more holes to seal up but it is still doable.
(Pseudo) guru Lee
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I worked with Mauro in my previous life when we decided making our own production test gear for speakers was becoming a PIA. Excellent people and his level of support rivals B&K, Naerum. Some of my ideas went into ClioQC which I highly recommend to anyone doing production testing.
I introduced Clio to China and it is now a de-facto standard in Chinese factories. Sadly, there are also many Chinese clones. Please buy the original. It is not expensive for what it does & you support an excellent company.
Scott, what free software do you recommend for measuring speakers & mikes?
I've been searching for this mythical beast but have not found anything that is as easy to use. The closest is ARTA. But if you can afford ClioLite, buy it. Their inexpensive measurement mikes are probably the only ones whose calibration I trust.
If you do use some lesser package, I recommend you download the Clio manuals and study them carefully.
Optomic
Maybe they ran out of Unobtainium & virgins
Actually their latest 'specs' are much less outrageous than their original claims. Now about the level of a better than average electret omni.I've read the Optimic bumph and am frankly quite sceptical ... but it might be NIH syndrome on my part as I've never tried one in the flesh
Maybe they ran out of Unobtainium & virgins
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Few years ago I saw on AES subwoofers with feedback by pressure. They glued Panasonic capsules inside of a hole drilled in the case. I asked the guy if the capsule survives the pressure, he answered it even does not saturate.
By the way, probably tomorrow samples with optical capsules will be shipped. I am going to play with them and make a stereo array. If to combine them with vacuum tubes it can be a killing product!
By the way, probably tomorrow samples with optical capsules will be shipped. I am going to play with them and make a stereo array. If to combine them with vacuum tubes it can be a killing product!
Often the people who make microphones arent the best electronic circuit designers (with exceptions).... I would think that with the optical mic capsule, as it were, we here could do an excellent job of the receiving end of the light to voltage/current converter. Anyway, glad that some serious look at the technology has begun. [boy, sometimes, simple things are like pulling teeth here] Good for you - Wavebourn !! That's the spirit I like. Thx-RNM
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If you need to buy an external soundcard anyway, Clio may offer one with software included that's price-attractive and makes measurements a bit easier as the hardware & software should be better integrated.
jan
Got some good mikes to compare them with? AKG414 will do. If you can record something simultaneously with both, those versed in the art can do serious comparisons for response & noise. So record some silent bits too.By the way, probably tomorrow samples with optical capsules will be shipped. I am going to play with them and make a stereo array. If to combine them with vacuum tubes it can be a killing product!
Mr. Marsh, from your silence, I take it you haven't tried an Optimic.
I can borrow some most venerable mikes from Gearslutz forum members, if my own mikes are not the reference for someone.
However, would be great to have access to some acoustic measurement laboratory.
Omni-directional mikes are not very useful, in professional audio recording. We used them mainly for speakers; sport commentators, or journalists in news reportage, when we needed "close to mouth", because they do not suffer from proximity effects.
You can use them in artificial head for stereo recording, but it is not very "rock'n roll'.
We had only two of them (apart some ties mikes) in our park, on half an hundred of mikes, and i don't remember i had never turned a Neuman in omni position apart special situations.
May-be that is the reason why those light-mikes are not well known ?
Strange, because all good studios use to test all the mikes they can, as we used even very strange ones for particular effects.
It is a big part of the sound signature of a sound engeneer, the mikes he use for each instrument, and each one has his little secrets.
You can use them in artificial head for stereo recording, but it is not very "rock'n roll'.
We had only two of them (apart some ties mikes) in our park, on half an hundred of mikes, and i don't remember i had never turned a Neuman in omni position apart special situations.
May-be that is the reason why those light-mikes are not well known ?
Strange, because all good studios use to test all the mikes they can, as we used even very strange ones for particular effects.
It is a big part of the sound signature of a sound engeneer, the mikes he use for each instrument, and each one has his little secrets.
Right, today audio engineers on "all good studios" know the same "little secrets" and use rusted Neumann mikes for vocals and bent and dented SM-57 for guitar cabs.
Oh no, they use exactly mikes that were used to record famous performers, for corresponding genres. They believe that if to use a mike used to record Frank Sinatra their clients will sing the same, and gain the same popularity.
Who was recorded by optic mike? Nobody yet. But if to record some famous rapper they would know "the little secret" that optic mikes are good for rap.
Oh no, they use exactly mikes that were used to record famous performers, for corresponding genres. They believe that if to use a mike used to record Frank Sinatra their clients will sing the same, and gain the same popularity.
Who was recorded by optic mike? Nobody yet. But if to record some famous rapper they would know "the little secret" that optic mikes are good for rap.
Do you really think all sound engineers are stupid and don't know what they are doing ?
Or is-it just your pleasure to contradict every word I write ?
No engineer i knew, in France, US or England used the same set of mikes, except Neumann for some voices, and not the same models, and not always, and for very good reasons, along with Audiotechnica, Schoeps ... and even Russian mikes.
I had my old tube U67 (not rusted) with the internal grid removed, chosen between a lot of them after i fell in love with it 35 years ago. A miracle.
Mikes sets in studios are very different from one country to the other. When i was young, it was very difficult to find those fantastic electrostatic Shoeps in the US, by example. As well Electrovoice where very rare and unknown in France.
I had never used any Shure mike in studio. For guitar cabs, choice depended of the guitar or amp and the way the guitarist played. My favorite for saturated Gibson was an AKG double coil, D.202, a Sennheiser MD 441 for sharp sound and some others for different sounds. What do you believe ? It was not often that i recorded two drums kits the same way.
I know nothing about rap and i cannot listen-to. I believe they copy the sounds WE (our generation) created...
While we tried each record to sound different.
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"Christophe, the first keyword was: "today", the second was: "
I'm Sorry, Wavebourn, forgive-me. I'm too upset about this story of "copy".
In the 90s, when they arrived in studios with their rhythm's machines, synthesizers everywhere, and asked sound of guitar like Dire strait or... copy, copy; i knew it was finished for me and all my friends musicians, because we will be unable to afford that new period.
The previous disco period was painful enough, those robotic drummers ...
So i decided to change my media for movie and tv... It was a new country to explore, very antic, technically...
If there is no more music, at least, noise and dialog is less disagreeable to work with than music you don't like, see what i mean ?
But, believe-me, it was a very sad and bluesy period, music was my life, and i'm not yet consoled...
I have sold my Neumann, imagine...
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Unfortunately, there is too much 'expertise' being thrown around, amounting to little or nothing.
We used Shure or Electrovoice mikes for the GD in the early years, because they were almost overload proof, and sounded 'OK'. Of course condenser mikes were more 'delicate sounding' and Santana would add them when recording for that reason.
Later, we used B&K 4133 1/2" omni condenser mikes with 40K bandwidth, and they were clearer, without overloading, like the Neumann mikes might, if stressed.
Specific choices of mikes usually were insisted on by individual performers who might find that a particular mike's characteristics fit their voice. They would often supply the microphone, themselves, to make a recording.
People are NOT stupid, and even if we do not agree with them, and they, on the other hand, might not agree with us. It depends on what they want, sonically.
'Laughing' at the experience of others, is unprofessional.
We used Shure or Electrovoice mikes for the GD in the early years, because they were almost overload proof, and sounded 'OK'. Of course condenser mikes were more 'delicate sounding' and Santana would add them when recording for that reason.
Later, we used B&K 4133 1/2" omni condenser mikes with 40K bandwidth, and they were clearer, without overloading, like the Neumann mikes might, if stressed.
Specific choices of mikes usually were insisted on by individual performers who might find that a particular mike's characteristics fit their voice. They would often supply the microphone, themselves, to make a recording.
People are NOT stupid, and even if we do not agree with them, and they, on the other hand, might not agree with us. It depends on what they want, sonically.
'Laughing' at the experience of others, is unprofessional.
Begun and ended long before you brought this up. You never did answer the question of whether this is something you've actually tried...
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