> Yes, the known trait of front-rear confusion. What are you asking
> about it exactly?
Hi Rob,
Good, there is name for it, "front-rear confusion." And I think I must have it:)
> Are you thinking that almost equal amplitude sensitivity to the rear
> contributes more to the effect of the bass being more centralized
> around the speakers with Jecklin? It could some above 500 Hz, but
> response to the lowest octaves I'm discussing is very
> omni-directional for most arrays.
I guess I missed your original point. I think I was listening to something a
bit different than you - certainly above 500 Hz. More a hiss from the left that
seamed to encroach, I am guessing it was aspen leaves in the wind. The
localization seamed missing, just left channel but no sense of distance. I am
not trying to knock Kevin's recording here: I think the recording as nothing
less than amazing.
> Front-rear confusion typically becomes a concern when one wishes to
> locate sound sources accurately opposed to capturing as many events
> as clearly as possible. For example SASS produces (a) significantly
> lower amplitude when the sound arrives at angles greater than 90
> degrees off axis. (b) tonality that is noticeably warmer and (c)
> depth cues (such as reflections from surfaces in front of the array).
It is also worth considering when trying to capture a perspective that just
sounds natural. Even the SASS with MKH 20's will produce an unnatural bounce
back effect with direct flyovers. Think a billiard ball bouncing of the rail -
not very natural for a mallard duck. Lang Elliot pointed that one out to me
several years back a a NSS workshop.
> M-S arrays with a cardiod mid mic produce some of the (a) and (b)
> effects. X-Y and ORTF with cardioid mics do as well.
> Front-back distinction with Perpendicular to Boundary arrays is a
> challenge and therefore these arrays are good when wants to pick-up
> sounds from the rear with almost equal clarity. Blumlein is very good
> for this too. Jecklin Disk and Spaced Omnis produce less of the (a)
> and (b) effects than M-S and X-Y in my opinion.
Maybe off axis attenuation and/or coloration have a place in reducing
front-back confusion. I certainly have played with that with NT1-A's, though
I'm not sure I made much progress. More practical perhaps is careful scrutiny
on location for potential off axis problems.
John Hartog
> Large diaphragm mics are inherently more directional and tend to
> produce less front-back confusion (except for Rode NT2000's which are
> actually hotter at 90 degrees than at 0 degrees in omni mode).
Rob D.
>
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