Hi All
Following comment by Emanuele and Haken in previous posts on this topic I
decided to compare the performance of the MX391s in the new boundary rig with
AT3032s in a similar rig. Another reason for the test was to better asses the
stereo field because the initial test recording seemed to have a hole in the
middle (probably due to the presence of a building directly in front of the
position of the rig).
With all this in mind i went out to a local beach this morning and set up the
two rigs. Both boundary rigs are built in exactly the same way using the same
materials. The only difference being the distance between the boundary plates
-
the MX391 ones being slightly wider apart to cater for the difference in
capsule
diameters of the two types of microphones. For both rigs the distance between
the centres of the capsules is 5 7/8 inches (150mm). The face of the
capsules
in both rigs are 1 inch (25mm) from the front of the boundary plate.
The Olympus LS-10, on pip power, was set to record level High 5 and the
Marantz 661, with phantom supply to the AT3032s, was set at record level 6.5.
WAV at 16, 44.1 was used.
Photos taken during the test are in the picassa album. The captions to the
photos will give a bit more background
https://picasaweb.google.com/G0SBW.PM/AT3032MX391BeachTestFebruary142012?authuser=0&feat=directlink
Two snippets of the same period of the recording are on Soundcloud below. The
first 90 seconds are from the AT3032 and the second 90 are from the MX391. The
time of the samples covers the period when the surveyor was walking in the sea
in front of the rigs (see photo captions) The tapping of his survey wand on
the
sea floor can be heard. Other than applying fades in and fades out and
converting to MP3 320 no sound editing has been used.
http://soundcloud.com/g0sbw/at3032-mx391waves
To my ear the MX391s sound slightly more crisp.
When listening on headphones a deep throb can be heard on both snipppets. It
sounds like an engine of the type of boat which services the offshore wind farm
just visible in the first photo. I was not aware of a boat or the noise at the
time of the recording.
Hope the test is of use to those interested.
Cheers
Tom Robinson
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