scottman said:
Back to the original question:.... I spend a lot of time on the same question, I even made a attempt by taken a yellow PCV tube ands drilling holes in it... similar to the Sennheiser designes..
I left the project because I couldn't find enough information about the design principles,
So if anybody has some info on the design preiciples of the shotgun mics.. I would be very interested...
Don't give up so fast!
Scott
The design that you have in hand is very close to that of a pro mic. The wave length problems are used to create a null point between the two capsules as you already deduced. There is more info available if you want. I just have to gather the articles and mail it over.
Mark
Scott
The design that you have in hand is very close to that of a pro mic. The wave length problems are used to create a null point between the two capsules as you already deduced. There is more info available if you want. I just have to gather the articles and mail it over.
Mark
There is a DIY mic group on Yahoo - I read it from time to time.
Might be a good place to search.
http://groups.yahoo.com/group/micbuilders/
Might be a good place to search.
http://groups.yahoo.com/group/micbuilders/
Hi everyone,
Been away for a while - got distracted by the holidays, and I'm not sure this email notification thing is working, even though I've got it checked and have kicked it a few times.
Anyway, the Yahoo groups is a great resource, though I have yet to find exactly what I'm looking for. And, Mark, any info you can provide would be most appreciated.
Thanks much,
Scott
Been away for a while - got distracted by the holidays, and I'm not sure this email notification thing is working, even though I've got it checked and have kicked it a few times.
Anyway, the Yahoo groups is a great resource, though I have yet to find exactly what I'm looking for. And, Mark, any info you can provide would be most appreciated.
Thanks much,
Scott
Will do, Michael. (BTW, your new web site is looking great.) I'm terribly scattered lately looking for steady employment but intend to pursue this matter until I'm able to successfully build a great condenser (or dynamic) shotgun mic (ported tube type), at which time I'll post construction details for my fellow diyAudio geeks.
Time permitting, I'd also like to play with the dual and/or multiple capsule arrays (front mic being out-of-phase with one or more rear capsules) out of sheer curiosity since "wxn" astutely pointed out that the acoustic tube's down side is that it's actually a "directional attenuator", hence requiring the transducer and associated electronics to have stellar s/n specs. The multiple capsules may well address this issue and possibly outperform the acoustic tube in this regard.
As an aside, my only other desire at this point would be for all forum posters to divulge either their real names, or names by which they'd like to be addressed, so I can feel like I'm chatting with real humans.
Scott Morrison
Time permitting, I'd also like to play with the dual and/or multiple capsule arrays (front mic being out-of-phase with one or more rear capsules) out of sheer curiosity since "wxn" astutely pointed out that the acoustic tube's down side is that it's actually a "directional attenuator", hence requiring the transducer and associated electronics to have stellar s/n specs. The multiple capsules may well address this issue and possibly outperform the acoustic tube in this regard.
As an aside, my only other desire at this point would be for all forum posters to divulge either their real names, or names by which they'd like to be addressed, so I can feel like I'm chatting with real humans.
Scott Morrison
A friend of mine suggested I do a patent search to see how these commercially available shotgun mics are designed. Makes perfect sense. Now why didn't I think of that? I'll be happy to share my findings.
Thanks to those who let us know who your are. Though this is completely off-topic and should perhaps be addressed to the forum administrators, I guess the more appropriate question would be: "By what name would you like to be addressed on this forum?" When applying for membership, it would be cool to have such a field to fill in. I don't think the "user name" field can address this because I'm not sure they allow duplications, even though many of us have the same birth name. Oh well. Perhaps my user name should be "anal" for I may well be the only person concerned with this.
Scott
Thanks to those who let us know who your are. Though this is completely off-topic and should perhaps be addressed to the forum administrators, I guess the more appropriate question would be: "By what name would you like to be addressed on this forum?" When applying for membership, it would be cool to have such a field to fill in. I don't think the "user name" field can address this because I'm not sure they allow duplications, even though many of us have the same birth name. Oh well. Perhaps my user name should be "anal" for I may well be the only person concerned with this.
Scott
Hi folks,
In doing a bit of research on the question of shotgun microphone magic, I had been trying to get information on the design and construction of the tv/film "standard", the Sennheiser MKH 416, in an effort to build my own for another purpose. I attempted perusing patents and got way in over my head. However, while visiting other forums, I became intrigued when the Sanken CS-3 kept showing up as a favorable alternative to the Sennheiser MKH 416. The Sanken folks are more forthcoming about their design on various web sites, likely as a marketing tool, so hence I was able to find the following:
http://www.sanken.ch/english/cs-3.htm
http://www.soundmixers.com/index.php?manid=12&groupid=14&pid=51
http://www.trewaudio.com/sankencs3.htm
The Sanken CS-3 utilizes 3 directional condenser capsules spaced just so. The advantages of this type of microphone over those of the "mechanical tube" type, for lack of a better term, are that it cancels better at low frequencies, has less proximity effect, and can be physically shorter. The CS-3 is also lighter, but that may have nothing to do with these electrical vs mechanical approaches. I'm guessing that the MKH 416 is a single capsule "mechanical tube" type?
I may soon begin experimentation with the multiple capsule array in lieu of data on the other type.
Scott Morrison
Van Nuys, CA
In doing a bit of research on the question of shotgun microphone magic, I had been trying to get information on the design and construction of the tv/film "standard", the Sennheiser MKH 416, in an effort to build my own for another purpose. I attempted perusing patents and got way in over my head. However, while visiting other forums, I became intrigued when the Sanken CS-3 kept showing up as a favorable alternative to the Sennheiser MKH 416. The Sanken folks are more forthcoming about their design on various web sites, likely as a marketing tool, so hence I was able to find the following:
http://www.sanken.ch/english/cs-3.htm
http://www.soundmixers.com/index.php?manid=12&groupid=14&pid=51
http://www.trewaudio.com/sankencs3.htm
The Sanken CS-3 utilizes 3 directional condenser capsules spaced just so. The advantages of this type of microphone over those of the "mechanical tube" type, for lack of a better term, are that it cancels better at low frequencies, has less proximity effect, and can be physically shorter. The CS-3 is also lighter, but that may have nothing to do with these electrical vs mechanical approaches. I'm guessing that the MKH 416 is a single capsule "mechanical tube" type?
I may soon begin experimentation with the multiple capsule array in lieu of data on the other type.
Scott Morrison
Van Nuys, CA
Here are some sources for mic capsules!
Hi Scott
I found some sources for mic capsules that will be of some interest to you if you want to duplicate the Sanken microphone. The ones on page 2194 may bring you a little smile if you recognize them from the drawings that you posted earlier.
http://onlinecatalog.digikey.com/default.asp?BookCode=dus08flx&SectionIndex=0&PageIndex=2194
Mark
Hi Scott
I found some sources for mic capsules that will be of some interest to you if you want to duplicate the Sanken microphone. The ones on page 2194 may bring you a little smile if you recognize them from the drawings that you posted earlier.
http://onlinecatalog.digikey.com/default.asp?BookCode=dus08flx&SectionIndex=0&PageIndex=2194
Mark
Hi Mark,
Thank you for the resource. However, I think you may have lost me. If you're referring to these Sanken drawings...
http://www.sanken.ch/english/cs-3.htm
...they lack detail and I cannot tell from same if they correspond to a particular Knowles model on that Digikey page. Do you think Sanken is using a particular model of Knowles capsule from that group? Also, there are some other details lacking (probably for good reason) that would prevent a guy like me from producing a CS-3 knockoff.
I've been ordering capsules from Digikey since the late seventies, but always gravitated toward the Panasonic units because they state their frequency response (and I've tested most of them). Knowles and many others do not, so it's pure guess work. (I don't know how on earth they can expect a customer to make a wise decision when such a critical specification as frequency response is missing!) Long ago, I did order one each of the Knowles microphones (not this particular group you just pointed out - too expensive for that) just so I could see if they were usable for my particular application at the time. Well, they sounded horrible. They were all midrange and nothing else, which made sense because they were designed for hearing aids and hence focus on voice frequencies. (They still live in my parts box.)
With this new line of Knowles models that you pointed out, I'd love to know how they sound, but without a published frequency response and each capsule costing upwards of $40, it's an expensive proposition to test even a few. Plus, for the project I'm designing, if I were using as few as 2 shotgun microphones, requiring 6 capsules, it would get very expensive very fast.
Otherwise, I was considering buying some more of my old two-dollar standby's, the Panasonic WM-55A103 (unidirectional) and the Panasonic WM-61A (omnidirectional) (Digikey page 2193) to experiment with this multi-capsule array. They're not the greatest capsules in the world, but they're still pretty good, and the best I could find by cherry-picking Digikey's offerings.
Looking forward to any further insights you may have. Thanks again.
Scott Morrison
Van Nuys, CA
Thank you for the resource. However, I think you may have lost me. If you're referring to these Sanken drawings...
http://www.sanken.ch/english/cs-3.htm
...they lack detail and I cannot tell from same if they correspond to a particular Knowles model on that Digikey page. Do you think Sanken is using a particular model of Knowles capsule from that group? Also, there are some other details lacking (probably for good reason) that would prevent a guy like me from producing a CS-3 knockoff.
I've been ordering capsules from Digikey since the late seventies, but always gravitated toward the Panasonic units because they state their frequency response (and I've tested most of them). Knowles and many others do not, so it's pure guess work. (I don't know how on earth they can expect a customer to make a wise decision when such a critical specification as frequency response is missing!) Long ago, I did order one each of the Knowles microphones (not this particular group you just pointed out - too expensive for that) just so I could see if they were usable for my particular application at the time. Well, they sounded horrible. They were all midrange and nothing else, which made sense because they were designed for hearing aids and hence focus on voice frequencies. (They still live in my parts box.)
With this new line of Knowles models that you pointed out, I'd love to know how they sound, but without a published frequency response and each capsule costing upwards of $40, it's an expensive proposition to test even a few. Plus, for the project I'm designing, if I were using as few as 2 shotgun microphones, requiring 6 capsules, it would get very expensive very fast.
Otherwise, I was considering buying some more of my old two-dollar standby's, the Panasonic WM-55A103 (unidirectional) and the Panasonic WM-61A (omnidirectional) (Digikey page 2193) to experiment with this multi-capsule array. They're not the greatest capsules in the world, but they're still pretty good, and the best I could find by cherry-picking Digikey's offerings.
Looking forward to any further insights you may have. Thanks again.
Scott Morrison
Van Nuys, CA
Stupid is as Stupid Duzz
Hi Scott!
The post I put up about the capsule was a real dumb mistake. Those mics are sub miniatures for hearing aids as you stated. They have a reasponse that is tailored to the gain and losses when place in the ear canal or the ear itself. So pretty much useless.
I am going to be getting home tonight and I will send you the rest of the elektor articles. They are to big to post.
As a group of information they give you what you need to figure out. And most of the circuitry to get it done. There is no reason why you cannot reverse engineer the Sanken mic from the drawings and the specified length. The tube is fairly easy to figure out and the mic capsules that you have on hand are worth a try. The only question that I have is whether or not a directional capsule will work better in this application. My gut tells me that it would but I will read the articles that I post tonight so that I have a bit of a refresher.
Mark
Mark
Hi Scott!
The post I put up about the capsule was a real dumb mistake. Those mics are sub miniatures for hearing aids as you stated. They have a reasponse that is tailored to the gain and losses when place in the ear canal or the ear itself. So pretty much useless.
I am going to be getting home tonight and I will send you the rest of the elektor articles. They are to big to post.
As a group of information they give you what you need to figure out. And most of the circuitry to get it done. There is no reason why you cannot reverse engineer the Sanken mic from the drawings and the specified length. The tube is fairly easy to figure out and the mic capsules that you have on hand are worth a try. The only question that I have is whether or not a directional capsule will work better in this application. My gut tells me that it would but I will read the articles that I post tonight so that I have a bit of a refresher.
Mark
Mark
Much obliged, Mark, for all the Elector stuff. I've been preoccupied with another project lately so haven't yet been able to experiment with the capsule array for the shotgun microphone but am dying of curiosity and chomping at the bit to get to it. Like you, I suspect that the uni-directional capsules will work best, but you never know.
And for those who give a hoot, I'll post what I learn as I go.
Thanks again,
Scott
And for those who give a hoot, I'll post what I learn as I go.
Thanks again,
Scott
The theory behind the popular electronics mic is not so different to that of the tubular shotgun mic.
The tube with slots down the side is called an interference tube. Sound waves entering at the end of the tube will travel to the end and all be in phase when they reach the mic capsule therefore will be additive. sound waves entering the tube along the side, i.e. through the slots will enter at different points along the length of the tube and be reflected towards the capsule, sound from different slots will have travelled different distances and will not therefore be in phase at the capsule and will be subtractive to varying degrees.
So to summarise, sound which is subtractive will be at a lower overall level than in phase additive sound, meaning that the higher levels are produced from the front of the tube and those at the sides will be attenuated.
Hope this helps.
Jilly.
The tube with slots down the side is called an interference tube. Sound waves entering at the end of the tube will travel to the end and all be in phase when they reach the mic capsule therefore will be additive. sound waves entering the tube along the side, i.e. through the slots will enter at different points along the length of the tube and be reflected towards the capsule, sound from different slots will have travelled different distances and will not therefore be in phase at the capsule and will be subtractive to varying degrees.
So to summarise, sound which is subtractive will be at a lower overall level than in phase additive sound, meaning that the higher levels are produced from the front of the tube and those at the sides will be attenuated.
Hope this helps.
Jilly.
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