Hi Paul
In some of the literature on boundary effects, it is suggested that
if boundaries don't exceed 5" in any dimension the impression of the
bass response is improved. David Michael has been testing this
variable today by coincidence. I'm sure he'd love for folks to follow
and comment on his progress and findings at
http://soundcloud.com/dmichael/sets/stereo-array-testing-mkh3040-at4022
The argument for not reducing the boundary further might be that the
Hz "lift" produced by the boundary will get higher in pitch as the
boundary size gets smaller. For example, the fundamental wavelengths
for a 4X6" rectangle would be:
4" side: 13280 inches per second (spd of sound) / 4" =3D 3320 Hz
6" side: 13280 inches per second / 6" =3D 2213 Hz
The spaciousness some appreciated with the SASS comparison was
promoted by a lift in the 400-1900 Hz range so there's more to it
than boundary size. SASS boundaries for reference are 3- 5/8" wide
and 4-15/16" high. It uses a capsule setback of only 5/8". Rob D.
At 8:43 AM +1000 3/22/10, Paul Jacobson wrote:
>
>
>Hi all,
>
>I'm wondering if there was any limit to how far the barriers could be
>reduced before they ceased to be effective? It seems the forward edge
>setback requirement is minimal - around 0.5 to 1.5 inches. The length
>of the barrier behind the capsule seems to be designed to function
>primarily as a mount for the mic.
>
>I wonder if this rear offset could be reduced to 1.5 to 2 inches
>without effecting the rig performance?
>
>The same question extends to the height of the barrier. Could this
>dimension be reduced without negative effect?
>
>cheers
>Paul
>
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