EEVblog - 2014-04-19
Doug Ford, former head designer from Rode Microphones continues with Part 2 of the microphone technology series by explaining the construction of noise cancelling Figure 8, cardioid, and hyper cardioid microphones. Also, how the polar patterns and responses relate to the physical construction, and how the frequency response is affected. Proximity boost effect, Microphone calibration is also discussed using a home made artificial voice speaker box. And practical considerations about foldback wedges used in stage performances and how to avoid feedback using proper microphone technique. And did Jimmy Barnes offer Doug a swig from his bottle of Vodka? Forum: http://www.eevblog.com/forum/blog/eevblog-605-microphone-patterns/ www.dfad.com.au EEVblog Main Web Site: http://www.eevblog.com EEVblog Amazon Store: http://astore.amazon.com/eevblogstore-20 Donations: http://www.eevblog.com/donations/ Projects: http://www.eevblog.com/projects/ Electronics Info Wiki: http://www.eevblog.com/wiki/
Love it. Interesting hearing the theory of how aviation mics actually work and not any of the marketing garbage.
This is absolutely amazing. Can't wait for MORE!
Cheers Doug, cheers Dave! Nothing beats hearing things from the mouth of an experienced engineer who has been there and done that!
Ecky thump! I bet Doug used to watch The Goodies in the 70s and 80s too ;)
Great mic videos so far, Dave! I've learned a whole ton about microphones that I never knew before! Can't wait for the next one! Thanks again Doug and Dave!
Another great episode of the Doug and Dave Show! :-)
Excellent video Dave and Doug. I think it would be great if you guys could make this format of video a regular fixture in your weekly schedule.
Another great video Dave, sure you've learned even more about audio with this one!!! :-) Keep them coming mate!
Thanks Dave and Doug this series is awesome!
Thank's Dave & Doug for another excellent documentary on mic's.Could Doug do some more documentary's please say audio mixers ?
fundamental Friday must have Doug with you always. even when the expert in some subject are you. he must be there to ask questions. its great to have you both.
My favorite mike for large ensemble recording is a royer ribbon (stereo mike) --- gets natural sounding reverb from the 'house' and a very neutral sounding orchestral pickup. NOT a mike I would consider for lots of things because of the wind sensitivity.. (That ribbon does not take well to wind... or air conditioner drafts)
I really hope they talk about Heil microphones and how different they are from regular cardioid and figure 8 type cartridges.
It was a pleasure to watch this. Solid knowledge without boring. Doug have very pleasant way of narrating.
I love it. You should make some altzone videos of just you and Doug sitting around telling stories!
Please show more things like this!
#EEVblog #605 - Fig.8 & Cardioid Microphone Patterns I wish he'd also talked about the high-frequency limitations of figure-8 mics.
When designing a ribbon mic it's important to make the front-back path as short as possible, because when the wavelength gets to be around that distance the sensitivity plummets, just like with very low frequencies...
When I designed my Berkley-1 ribbon mic, I used the neodymium magnets as the sids of the frame, thereby shortening the front-back path as much as possible with the given strength/size magnetic. https://3dwarehouse.sketchup.com/model.html?id=7d0cc303be24f5d99ec8b617971abb3f
Great video! One question: how is cardiod done without two physical elements? At 13:00 came the question "And they're all constructed like that, physically using two elements?" Doug: "No. ... And this is where the black magic comes in". But I don't think the question was ever answered...
It’s done by means of an acoustic labyrinth, so the construction of the capsule is such that sound arriving from the back is delayed in a way that it cancels with the sound at the front. Acoustic cancellation within the body of the mic, rather than the two capsule electrical cancellation.
@Brain Washer Excellent,.thanks for the answer! Oh, that's some clever design. After I wrote that question 8 years ago, I didn't do follow up research (probably forgot I asked the question by the next day) so am learning about this now. Now to do some extra reading on how these labyrinths deal with different frequencies...
I have gotten in about 8 minutes but wondered about a figure of 8 mic having a "natural" compression (gain-control) effect on close-in sources as the sound from the 'front' finds it's way around to the back the even though the square law would have a profound effect would there be some "natural automatic" gain-reduction effect as well?
FYI Helmholtz Resonance formulas describe how the resonant freq can be determined for different geometries, not only cylindrical passages. This method is used to "tune" the resonant response of compression waves created by valves in an engine.
http://en.wikipedia.org/wiki/Helmholtz_resonance
Awesome video, Doug and Dave - loved the explanation of effects of physical designs!!
Watching Dave making commentary from behind almost makes this feel like MST3K.
I love how he's always half wrong
came here from the teardown of the condesor mic, hit by the water flood in the eev labs. this so interesting. thank you very much!
This guy really does explain things well. I'm quite a nube with electronics and audio yet I still understood quite well everything he talked about. By the way, how much effect does the natural resonance of the wobbly diaphragm have on the frequency response of the mic?
Also have to say we have a range of mountains here in the US named by some french dude that resemble that frequency response curve of the last mic.
mic diaphragms are often made of mylar and incredibly thin and light, so they can pickup quiet sounds and have an accurate freq response (theyre very low mass so they can react quickly to higher frequencies). the resonant freq would be so high i doubt it would make a difference
how on Gods earth with all my interests in electronics, music, music production, amplifiers, synthesisers, DAWs etc..... has You Tube only pointed me to this today in 2022!!!!!!?????? This is a truly awesome series worth its weight in Solid Gold!!!! Sometimes you just have to despair with YouTubes algorithms. I don't need to see another funny cat! more of this stuff! Love your channel btw.
Don’t care a whip about microphone design but can’t stop listening and watching this guy.
Figure 8 and Cardioid Microphone Patterns rule.
Great, fave eev video series
Great video, love his personality
So, I am wondering if Doug has ever considered that a 'Figure 8' polar pattern (when used in Mid/Side) functionally becomes a 'mobius' strip, which is why we are able to build an electrical Mid/Side decoding matrix to transform mid/side into a traditional A/B stereo configuration. 180 - (-) 180 degree phase inversion of the side mic with respect to proximity eliminates the inverse square law attenuation ramifications by phase doubling (electrically) certain frequency response magnitudes precisely because others are being cancelled out between the MID and Side information Inversely in A/B (which manifests as an Asymmetrical Balance as opposed to traditional Symmetry). So, when combined with the MID, there is a 100% cancellation at the MID and 100% phase inversion on the 'sides' of the stereo image (if the mid is pan center and the sides are pan L and R respectfully). So, stereo Pan Law actually 'means' something in the MS context, because in traditional stereo, I cannot lower and raise the 'side' informational volume independently of the mid (unless I build the MS matrix).
So, lets extrapolate this conversation into a 'Conventional' Physics. Are we misunderstanding 'Magnetism'? Is a 'magnetic' field a Figure 8 Pattern?... YES.
Are there actually Side 'sets' of information in MID/SIDE? NO.
So, my question becomes... If N/S are actually the 'same' information set in a magnetic field, would there actually be 2 polarities? No.
There would be only 1 property of magnetism (magnetic flow, MID) and then the 'duality' of polarity is an Illusion created by the decoding of an electrical MS matrix into A/B stereo, by way of a Möbius strip. Thus providing -180 to +180 inversion of Polarity between the 'poles' of the magnetic matrix.
Are there actually (2) Side 'sets' of information in MID/SIDE? NO, there is only 1 monophonic electrical form which is duplicated and phase inverted and panned L and R.
Does a magnetic field has a ring of silence? YES... So, how would it change our understanding of electrical engineering to understand magnetism as a MID/SIDE stereo as opposed to an X/Y stereo construct?
Perhaps... attraction and repulsion are actually the result of N/S and N/N or S/S...as Chiral Information sets which can shake hands or not. N/S is actually like 2 'right' hands of 2 different people. Each person believes in their own N/S, but they only know which is which when they meet another polarized state.
Great, fave eev video series
It's a good thing that one can hear all the background noise from callcenters, time to hang up the phone & add the number to the phones "blacklist"
I understand that Bob Heil is probably better known for his concert sound systems, but how do Heil's microphones compare to microphones designed by Doug Ford?
How do phones capture sound so well on tye normal mic for calls? And how does one replicate this for earbuds or lapel mic
Excellent!
Awesome !
We want more!!' :)
Why isn't this the second video in the playlist?
Bring back doug for mmmore stuffs!
You can edit out the plalalalala's can't you?
Yes... [laughs in electrician]
Very interesting.
hopefully there is more...just for learning about it...
very interesting
i wonder why hes poining out the peaks at the end of the vid again! :D
Hmmmmmmmmmmmmmmmmm I'm curious which mic polar pattern most rezembels the actual ear drum. I thought omni, but someone replied to my youtube comment saying they figured figure 8. I've never used figure 8 mics on their own so don't really get how they work. Thus why I'm listening to the vid. But meh there's things about figure 8 that don't add up for me to think that would be what the human ear drum is.
Well, Theory sucks a the beginning but is enjoyable and enlightening at the end. Maybe few slides could help instead of that classic whiteboard. Anyway, I already appreciate the information provided.
6:33 Dave turns head towards the camera, sticking tongue out for no apparent reason.
So fig 8 is for musicians ?
Theory back by a drill bit that our Douglas
Microphone again!!!
He's no Walter Lewin.....
Console - 2014-04-20
This is awesome. Doug is clearly a guy who loves his job, an extremely knowledgable and entertaining guy. Cheers you crazy Aussie bloke, I'm not an audiophile or audio guy but have found the series incredibly interesting. Absolutely bloody brilliant.