Hi-Rez Highway: Re: The reality of figure of 8 microphones by Jean-Marie Geijsen

A couple of remarks about what you said.

â€œBoth types are a compromiseâ€, you are referring to ribbons and condenser micâ€™s I believe, and if so, yes you are right. But every microphone is a compromise.

â€œCondenser micâ€™s are prone to capsule resonanceâ€, yes you are right again, but to be more correct, every microphone, ribbon, coil or condenser mic, is prone to capsule resonance.
A more interesting question is where this resonance is located. For omnidirectional condenser microphones like the DPA 4006 or Schoeps mk2(s) this resonance is somewhere close or even above 20 kHz. (I do not consider a U47 to be a real omni since it is a far to complex microphone not suitable for a main pick-up and does certainly not match the modern omni microphones like the ones I just mentioned ). For directional microphones like the Pearl ELM 30, this resonance is located at the low midrange, around 200 Hz. This capsule resonance acts like the before mentioned LP filter. So to check what microphone has the most pronounced capsule resonance we can do a simple test. Please check your ribbon microphone if it suffers from handling noise, then do the same with a DPA 4006 or any other high quality condenser omni. From experience I can tell you that the DPA 4006 is free of any handling noise. This means that the capsule resonance is hardly an issue. I do not know if the same applies to your preferred Pearl ELM 30, but your main microphone is probably always installed in a shockmount, to absorb handling noise and rumble.
You also state that â€œoften condenser microphones have some EQ build inâ€. I can tell you that I do not now any condenser microphone in our studio which has a EQ build in, also not hidden inside. We have about 200 Schoeps DPA and Neumann microphones, which I all have measured. The electronics only convert the appr. 1 GigaOhm capsule load down to a user-friendlier 50-200 Ohm output impedance.

Funny that you mention the transient behaviour of your microphone. Have you ever tried to record a square wave with a directional microphone and compared that to the output of an omni? Any directional microphone will show a nice transient as a result of an acoustic pressure step from 0 to 1, but will return to zero immediately after the transient has past, although the acoustic pressure input is still at 1. When the acoustic pressure drops again from 1 to 0, the directional microphone will again give a nice transient response, but from 0 to â€“1 !! When looking at the output from the omni: it will rise from 0 to 1, stay at 1 for as long as it needs, and drops down from 1 to 0 when it has to.
I will not mention the implications of this transient behaviour on the phase response of any directional microphone.

I must say that I find the membrane construction of the Pearl EML 30 really interesting. But due to its rectangular shape it will have a very unusual pick up pattern. In the horizontal plane it will behave like a figure of 8 should, but in the vertical plane it will behave completely different. In the vertical plane this microphone acts like an line pick up and as a result you will have a very coloured off-axis diffuse sound-field pick up including a comb-filter starting at 4.5 kHz upwards. This is truly a directional microphone and I can imagine some situations where this behaviour is welcome, but this is hardly the pick up (and sound colour) I would choose for my main microphone set-up.

A have nothings against the fact that you like the sound of the microphone, even when you say that this microphone delivers exactly the sound you hear in a concert hall, but I can also imagine that there are people who do not agree with you, and the physics prove them to be right.

I must admit that there is one aspect where the crossed fig of 8 excels compared to other microphone set-ups and that is pin-point stereo image accuracy (if you sit exactly on the sweet spot), but is this the most important aspect of a recording? I believe perfect inner balance and tonal balance to be much more important for the music then the question if the flute is situated 10 degrees left to the centre, or was it 15 degrees?

Jean-Marie Geijsen