How does one build a shotgun microphone?

[tschrama]

Originally posted by scottman
I would like to build a shotgun microphone but cannot seem to find any information anywhere. (Not a parabolic type, for which there is much DIY info, but the conventional long tubular type used in tv/film.) Obviously, lots of design engineers working for established companies (Sennheiser, Azden, Audio-Technica, Shure, etc.) have it down to a fine art, but they're not talking.

Obviously, one could reverse-engineer a good microphone and fake it, but it would leave a lot of unanswered questions about the art/science behind these designs. For example, would one use an omni or cardioid capsule? What should the dimensions of the tube be, and what are the the trade-offs? How do those vents on the sides work? What controls the pickup pattern? The frequency response? Etc. Thanks much.

Scott Morrison
Van Nuys, CA

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...

[mwmkravchenko]

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

[Pano]

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/

[mwmkravchenko]

Thanks Panomaniac!

That's a veritable goldmine of info.

Mark

[wxn]

Originally posted by panomaniac
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/

That's where I got the idea of multiple capsules on a plane from.

[mwmkravchenko]

If it is not against the rules I would be happy to post the other couple of articles from back issues of Elektor Electronics. They contain some usefull info and reasonings on performance and trade offs.

Mark

[scottman]

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

[Pano]

Hey Scott, do let us know what you find. It would be interesting to see it here.

[scottman]

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

[wxn]

My name is Constantine