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EEVblog #602 - Introduction to Microphones
Posted by
EEVblog
on 12 Apr, 2014 04:39
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In the first of a series of videos tutorials on microphones, Doug Ford, former head designer at Rode Microphones explains the basics of how microphones work, the different types - carbon, dynamic, ribbon, condensor/electret, and how the omnidirectional pattern works.
Also, the internal construction of a high end measurement microphone.
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#1 Reply
Posted by
DutchGert
on 12 Apr, 2014 10:44
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Nice one, this was a topic that I litterly knew nothing about until now
. Thx!
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#2 Reply
Posted by
woox2k
on 12 Apr, 2014 12:02
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Yes, finally some audio stuff.
Looking forwards for follow-up videos to take this even further, this one was fairly detailed but got cut short in the end.
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#3 Reply
Posted by
lewis
on 12 Apr, 2014 12:07
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Woo hoo! Doug's back!
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#4 Reply
Posted by
EEVblog
on 12 Apr, 2014 12:14
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Yes, finally some audio stuff. Looking forwards for follow-up videos to take this even further, this one was fairly detailed but got cut short in the end.
Yeah, unfortunately there wasn't a huge amount of structure to the whole shoot, being very off-the-cuff and jumping over the place. Going to be hard to edit into sensible sections that flow.
But in the end it'll be essentially a big dump of info.
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#5 Reply
Posted by
Sionyn
on 12 Apr, 2014 13:26
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loved this glad Douglas has shown his head again (more please) especially his beastly power supply
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#6 Reply
Posted by
EEVblog
on 12 Apr, 2014 13:50
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loved this glad Douglas has shown his head again (more please) especially his beastly power supply
I'll be visiting his new lab shortly to check out what he calls "The Death Star". No, not a power supply, something a lot more exotic...
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Definitely looking forward to more, great stuff.
I don't mean to bust your balls here Dave (seriously, I love your work), but as a recording engineer I gotta admit I got a laugh out of seeing you walk into mentioning/suspecting audiophoolery a few times there haha. I see it on the forum a bit, where if anyone seems to mention the possibility of higher fidelity than an op amp stage on a coin cell they're assumed to be snake oil buying, magic rock placing, $5000 power cord using weirdos. Was really nice to hear Doug talk as a respectable authority on the matter and point out that high quality audio really is a complex topic, and not necessarily all bullshit. I'm really interested to see where the future videos go, both of you are great at explaining things but you also seem quite different in the angle you're coming from so I think it's going to make for some killer videos.
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#8 Reply
Posted by
delmadord
on 12 Apr, 2014 19:55
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Yeah our almighty Dave looks like he is actually learnig instead of teachnig us..I LIKE IT
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#9 Reply
Posted by
hi-Z
on 12 Apr, 2014 21:39
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Fascinating subject, loved it.
I'm surprised nobody mentioned anything about piezoelectric elements. That's the good stuff.
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#10 Reply
Posted by
dentaku
on 12 Apr, 2014 22:17
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It's great to see Dave learning about stuff from a field of technology he's not very familiar with.
Sometime it would be great to see a video about and electronic instrument of some sort, beyond Sagan's Yamaha keyboard. Modular (mostly analog) synths are very interesting and so are effects pedals which are very similar. Maybe you could do a teardown of one of Fran Blanches audio effects boxes if someone is willing to lend you one.
I'm more interested in synths and their VOCs, VCAs, VCFs, LFOs etc. than guitar pedals though.
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#11 Reply
Posted by
don.r
on 13 Apr, 2014 03:27
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I wonder how tubes (valves) microphone?
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#12 Reply
Posted by
calexanian
on 13 Apr, 2014 03:49
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I wonder how tubes (valves) microphone?
Are you referring to micro phonics in a tube? Well, Vibrations wiggling a grid rather than a diaphragm. Although a grid can be seen as a diaphragm with slots cut in it. There are two modes of transduction. One is direct action of altering plate current through physical vibration of the grid (The most common) and capacitive changes in the grid with the basic same effect. There have actually been purpose built microphone tubes for specific frequencies and measurements.
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#13 Reply
Posted by
sdscotto
on 13 Apr, 2014 05:49
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I got a real kick out of all the metric this and metric that followed by "this is a 1/2 inch reference mic"
Can't wait to learn more, in metric of course!
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#14 Reply
Posted by
99tito99
on 13 Apr, 2014 06:09
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Hey, I'm a Yank and I understand meters and feet!Cheers,
Mark
********************
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#15 Reply
Posted by
EEVblog
on 13 Apr, 2014 07:28
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I don't mean to bust your balls here Dave (seriously, I love your work), but as a recording engineer I gotta admit I got a laugh out of seeing you walk into mentioning/suspecting audiophoolery a few times there haha. I see it on the forum a bit, where if anyone seems to mention the possibility of higher fidelity than an op amp stage on a coin cell they're assumed to be snake oil buying, magic rock placing, $5000 power cord using weirdos.
Because that's were the laughs are, it's called taking the piss.
No, I do not assume everyone who wants good audio performance is an audiophool. Any indication you have of that is incorrect and of your own making.
Was really nice to hear Doug talk as a respectable authority on the matter and point out that high quality audio really is a complex topic, and not necessarily all bullshit.
Doug thinks exactly the same way about audiophools as I do.
But because I've done a video poking fun at audiophools, and love to poke fun constantly, I get incorrectly pigeon holed as thinking that anyone who listens to music and asks a question is an audiophool.
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#16 Reply
Posted by
DrGeoff
on 13 Apr, 2014 08:12
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Was Doug involved in the design of the original NT-1?
That's one of the quietest condensor mics ever made and still very handy for recording some vocalists.
BTW, some dynamic mics sound much better when terminated with a particular load impedance. For example, the SM57 is great into a 600 ohm load. A lot to do with the termination of the internal transformer to stop ringing.
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#17 Reply
Posted by
EEVblog
on 13 Apr, 2014 08:15
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Was Doug involved in the design of the original NT-1?
Yes, and he goes into the circuit design in a future video, and why it is so quiet.
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#18 Reply
Posted by
G7PSK
on 13 Apr, 2014 08:40
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Very interesting on the old carbon microphones, a balanced carbon rod microphone was one of the first electronic things I built (well more electro mechanical really) it was so sensitive that you could hear a fly walking with just a set of high impedance headphones.
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#19 Reply
Posted by
fcb
on 13 Apr, 2014 08:54
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I wonder how tubes (valves) microphone?
Tube mikes - the tube/valve is just the local amplifier/buffer for the pick-up, in place of a FET.
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#20 Reply
Posted by
SeanB
on 13 Apr, 2014 09:26
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Microphones are available is various qualities, depending on how much you are willing to pay. Up to a point there is a near linear rise in performance, but if it is gold plated on the outside, and just junk on the inside it is Audiophoolery.
Carbon microphones are still in use in intercom systems, as they are pretty insensitive to hum on the supply lines, and survive lightning strikes nearby. I did upgrade a couple though using a spare electret insert and a single PNP germanium transistor along with a bias resistor across BE junction to set operating current into the speaker in class A in an intercom. More sensitive and less noise, but only done as the carbon no longer responded to banging and I could not get a replacement quick, as they were out of stock, and only offered a complete indoor unit at a price. Biggest killer of the carbon microphones are cleaners with spray furniture polish, which builds up a silicone oil coating on the granules.
Edit because I suddenly forgot how to spell correctly.
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I don't mean to bust your balls here Dave (seriously, I love your work), but as a recording engineer I gotta admit I got a laugh out of seeing you walk into mentioning/suspecting audiophoolery a few times there haha. I see it on the forum a bit, where if anyone seems to mention the possibility of higher fidelity than an op amp stage on a coin cell they're assumed to be snake oil buying, magic rock placing, $5000 power cord using weirdos.
Because that's were the laughs are, it's called taking the piss.
No, I do not assume everyone who wants good audio performance is an audiophool. Any indication you have of that is incorrect and of your own making.
Was really nice to hear Doug talk as a respectable authority on the matter and point out that high quality audio really is a complex topic, and not necessarily all bullshit.
Doug thinks exactly the same way about audiophools as I do.
But because I've done a video poking fun at audiophools, and love to poke fun constantly, I get incorrectly pigeon holed as thinking that anyone who listens to music and asks a question is an audiophool.
Haha nah man, I'm not lumping you in the extremist category, that forum reference was in regard to a bunch of threads I've seen (and particularly one dude whose name evades me who always manages to steer high quality audio discussion into how much he hates tubes and people who use them).
Don't worry, us studio geeks think exactly the same about the audiophool world
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#22 Reply
Posted by
don.r
on 13 Apr, 2014 15:12
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I wonder how tubes (valves) microphone?
Tube mikes - the tube/valve is just the local amplifier/buffer for the pick-up, in place of a FET.
LOL! Not what I meant. A tube can start to "microphone", i.e. acts like a microphone itself (act like a pickup) and I was curious about the physics involved there.
I wonder how tubes (valves) microphone?
Are you referring to micro phonics in a tube? Well, Vibrations wiggling a grid rather than a diaphragm. Although a grid can be seen as a diaphragm with slots cut in it. There are two modes of transduction. One is direct action of altering plate current through physical vibration of the grid (The most common) and capacitive changes in the grid with the basic same effect. There have actually been purpose built microphone tubes for specific frequencies and measurements.
Thanks. I thought it was the grid acting like a diaphragm.
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#23 Reply
Posted by
99tito99
on 13 Apr, 2014 16:18
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Hi Dave: Thanks to Doug and you for the video (and I gather a few more to come). I do not consider myself an audiophile nor an audiophool, but I do like good music reproduced well and I like learning about thing I don't know much about. Cheers, Mark * * *
PS
When I was a kid (12 - 14?) I got hold of a carbon microphone and of course I did not "Plug It In, I Took It Apart." It was a big sucker on a stand, probably from a Ham transmitter. As I recall it contained about a teaspoon of carbon granules that were glossy black and about the size of table salt (~1/3 - 1/2 mm).
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#24 Reply
Posted by
Bored@Work
on 13 Apr, 2014 16:41
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When I was a kid (12 - 14?) I got hold of a carbon microphone
When I was a boy
(TM) we built our own from the carbon rods of old batteries. A bit difficult today with almost only alkaline or rechargeable batteries around.