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Re: Machine Gun microphone

Subject: Re: Machine Gun microphone
From: "Michael Oates" msohooates
Date: Fri Sep 7, 2007 11:51 am ((PDT))

Thank you very much for your message, it's not really what I wanted to hear=
, but if it's
not going to work well for birds and animals, then I won't pursue it furthe=

So what I am gong to make first is a Jecklin disk with a pair of Sennheiser=
 MKH20's. This
is of course for general soundscape work. I will then progress to a parabol=
ic reflector. I
just need to source a disk, either to buy or make (I am in the UK) 24" bein=
g the smallest
with about a 4" focus. This I will us with both stereo (MKH20s with a scree=
n between the
mics) or a single one for mono work. Eventually (a long way off as these ar=
e expensive
mics) I would like to get an MS pair MKH40 & MKH30.

Thanks to all for the response.


>Well I guess I will weigh in on this topic. I built one of these in 1957
>because shotgun mics and parabolas were not available at affordable prices
>for my project. I was 10 yrs old at the time. I wanted to detect human
>voices, not birds. I think it works pretty well for voice stuff and my
>understanding is that in the 1950's, when I built one, this was one of the
>few ways to go for mechanical amplification. I don't know when modern
>shotgun mics were invented, but they would have been pretty pricy back the=
>Getting a parabola during the same era would also have been expensive, if
>you could find one at all. Parabolas were certainly around back then, but =
>it cost a few hundred dollars that was a fortune. A good car cost a few
>hundred dollars. Today, there is no advantage for natural sound recording
>because flat frequency response shotgun microphones allow quiet electronic
>gain to be applied to the signal. A parabola has all kinds of non-linearit=
>compared to the microphone, but is considered a wonderful tool nevertheles=
>The tube amplification will produce a whole series of holes in the frequen=
>response and will probably produce something so non-linear that the defect=
>could not be removed without a lot of work. I think this technology would =
>good to use as a historical comparison technology to show how far we have
>come in the last 50 years and it would be interesting physics project for
>the public to see in a sound museum. But for real recordings, its day has
>Greg Clark
>-----Original Message-----
> On Behalf Of Michael Oates
>Sent: Friday, September 07, 2007 10:44 AM
>Subject: Re: [Nature Recordists] Re: Machine Gun microphone
>Hmmm, Not sure if I want to go ahead with this if I am going to get lots o=
>the spectrum
>missed in the recording. The way I would build it, it would not be cheap. =
>I start to
>add up all the extra bits apart from the tubes, =A3200 is a more likely
>figure, so not
>exactly cheap just to try! And it would take a few weeks to make.
>I would like to hear from someone who had had some success with this type =
>especially if comb filter effects can be avoided. This could be the reason
>why information
>on this type of mic is hard to find and is widely being used.
>>I have had one of these since the 1970s. Built it from plastic
>>piping, and was never happy with the performance, but it does work.
>>It was the original shotgun microphone for those with little money.
>>Mine was originally built for a limited spectrum of sound with quite
>>a few fewer tubes than the project you plan. They are a fun project
>>if you want to try one. I'd be interested in how your project turns
>>--- In  "Michael Oates" <>
>>> Has anyone every made and used a machine gun microphone. There is
>>> much about these on the internet, but I have found this:
>>> I am concidering making one using 90 tubes of 8mm diameter
>>> tube with lengths from 1m down to 9mm. (That is two more rings of
>>> tubes than shown on the example making it 88mm diameter instead of
>>> 67mm) I was thinking of fitting a Rode NT1A as the condenser mic.
>>> I really want to know if anyone has tried such a beast. Based on
>>> length of tubes I would use, it should work from about 150Hz to
>>> range and appears to be very directional.
>>> My idea of using more tubes that in the example it to fill in the
>>> gaps in the frequency range, but I don't know if that's needed.
>>> Cost would be about =A3120 for the tubes plus a bit more for for
>>> fitting some windshield around it with fake fur on a wire frame
>>> former covering the full length.
>>> Thanks,
>>> Mike
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
>Yahoo! Groups Links

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