Topic: can a dual diaphragm mic be easily converted to output each diaphragm separately

[DSatz]

John W., no--putting it in rather blunt terms and omitting lots of variables, the capsule (and body) size affects mainly the high-frequency polar response, while the low-frequency pattern is more a function of a single-diaphragm vs. a dual-diaphragm construction. You can see this quite consistently in Neumann (Berlin)'s polar charts going all the way back, and there's plenty of math available to show why that is so.

--One other important variable in a dual-diaphragm system which can elude the usual graphs--polar graphs being drawn at certain "spot" frequencies while frequency response graphs are nearly always frontal--is the effect of the distance between the front and rear diaphragms. You mentioned this in one of your earlier messages, and rightly so, I think. It varies significantly among capsule designs--dual-diaphragm capsules should not all be lumped into one basket, as I'm sure you'd agree--but in general for the smoothest response in the upper midrange and high frequencies, the less that distance, the better. Unfortunately the reverse is true for the response at the lowest frequencies, particularly in figure-8 mode. To my ears the most attractive-sounding dual-diaphragm microphones have capsules that are rather slim when viewed from the side or top.

--best regards

[John Willett]

John W., no--putting it in rather blunt terms and omitting lots of variables, the capsule (and body) size affects mainly the high-frequency polar response, while the low-frequency pattern is more a function of a single-diaphragm vs. a dual-diaphragm construction. You can see this quite consistently in Neumann (Berlin)'s polar charts going all the way back, and there's plenty of math available to show why that is so.

--One other important variable in a dual-diaphragm system which can elude the usual graphs--polar graphs being drawn at certain "spot" frequencies while frequency response graphs are nearly always frontal--is the effect of the distance between the front and rear diaphragms. You mentioned this in one of your earlier messages, and rightly so, I think. It varies significantly among capsule designs--dual-diaphragm capsules should not all be lumped into one basket, as I'm sure you'd agree--but in general for the smoothest response in the upper midrange and high frequencies, the less that distance, the better. Unfortunately the reverse is true for the response at the lowest frequencies, particularly in figure-8 mode. To my ears the most attractive-sounding dual-diaphragm microphones have capsules that are rather slim when viewed from the side or top.

--best regards

I agree generally with what you are saying - I was just pointing out the quoted responses of three mics that have the same capsule and the widening was only apparent in the ones with the larger body.

The spacing in the UM930 is rather wide, more than a centimetre I think.

For a fig-8, personally, I always use a dedicated single diaphragm mic. , rather than a switchable.