Category Archives: Sound

Demonstration of 2 shot gun mics used for stereo recording

The following video was recorded using an XH-A1 and two on camera mounted long shot gun AT-835b microphones. This was not an ideal way to mount the microphones but it definitely performed “good enough”. When the camera and mics are a long ways from the field, there is not as much stereo channel separation as you might expect.

But the stereo mics add a depth to the sound that was missing when using a single shot gun mic. Why use a shot gun mic? The shot gun mic definitely records higher quality audio than the on camera mic and helps to reduce crowd noise.

The following is the performance of the Mt. Spokane High School Wildcats Marching Band at the 2011 Puget Sound Festival of Bands in Everett, Wa. MSHS band performed an original composition and this is posted on Youtube at the request of and with the permission of the band director.

Here is a photo of my set up for the recording. The two shot gun mics are above the camera. Output from the HDV camera is sent over a long Firewire cable to a Mac notebook computer, where the video stream is recorded direct to disk using QuickTime Pro. By recording direct to disk, the videos are immediately ready for conversion to MPEG4 without any time spent on import.

Stereo shot gun mic test clip

Test of my stereo shot gun mic set up – handholding the shotgun mic array in my left hand and holding my Canon HV30 and Beachtek audio mixer in my right hand. Not ideal, but an amusing little test clip. These birds were about 30 feet away from me, with a several hundred foot cliff just beyond. Pointing the long shotguns in that direction picks up some background noise – just noise – that is the city, miles away, bouncing off the cliffs. There is also a good sized stream behind me – they call it a river – which creates some background noise too.

I’ll try to eventually get a photo of the shotgun array set up. It’s two AT835b, 18 inch long shotguns, mounted in the crossed XY configuration. The mount is made from some PVC plumbing hardware, a piece of wood, and a paint roller handle – super high tech, the latest bit of Hollywood gadgetry, for sure. Or may be not. But its cheap and it works!

 

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Sound recording – and the need to avoid screaming kids!

An Audio-Technica AT815a shotgun microphone
Image via Wikipedia

As I have decided to pay much more attention to the sounds in my environment, today I took a pleasant hike along a meandering river – more of a big wide stream, really.

From a sound perspective it had great potential – burbling water, crickets, frogs, squirrels and chipmunks chirping, ducks and birds. Now that I pay attention to sound, I begin to hear interesting things everywhere.

But as my luck would have it, being a Sunday afternoon, I managed to time my hike in between several groups of screaming children. They had only one volume – FULL. A full quarter mile away and I could hear them fine with my own ears.

Twice I stopped to set up for sound recording – with a shotgun mic, a Canon HV30 camcorder, a Beachtek audio mixer, and an 18 inch shotgun mic. And twice I had to give up. If my ears could hear the screaming, imagine what that sounded like in a sensitive mic.

I learned something today – if trying to record natural environment sounds, I need to so so on weekday mornings, free of screaming kids. I had not planned today’s hike out very well, from an audio standpoint.

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Home made wind suppressing blimp for microphones

Photo taken in the Yellowstone area.
Image via Wikipedia

After dealing with wind one too many times, and especially in Yellowstone, I decided to build my own blimp. I assembled what you see in this photo:

After I built this, I discovered plans on the Internet for this same idea, even using the same components!

The tube is made from two inexpensive bird feeders, purchased at Home Depot. The sections are glued together using epoxy putty. Home Depot said they didn’t have any, but Lowe’s across the street, had Loctite, which is the same thing. I used two packages of Locktite on this.

The handle is a $1.68 paint roller handle, picked up at Lowe’s.

The end caps were made from two wire mesh sink drain covers, trimmed around and glued onto remnants of the bird feeder caps using more epoxy putty. The original bird feeder caps were drilled and then cut out with a jigsaw, leaving the rims.

I originally planned to weld the metal pieces together, but the bird feeder seems to be an aluminum alloy or something and was not weldable with my wire feed welder.

I still have to head to a fabric store to buy some fake fur to sew up a cover. That should happen within the next few days. I’ll try to post a followup picture of the final version.

Pros: Cheap, should work quite well. Can be mounted on any standard paint pole, as well as my 16 foot aluminum window washing pole.

Cons: the handle is not adjustable.

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