Topic: Doing figure 8 with two mics?

[it-goes-to-eleven]

Most good Figure 8 capsules are implemented with one diaphragm.

But I have been wondering.. Can you emulate a figure 8 capsule using two mics and a special cable?

I'm thinking invert the phase of the right channel and then combine with the left.  I did some searches but didn't come up with much.  Would this work?  Anyone tried it?  What pattern would be best for the mic pair?

[bhtoque]

You couldn't really do it like that. The fig 8 pattern is more stretched out than an "8" so combining 2 omni's would not give the same result.

If you are trying to do a m/s recording you could get away with swapping an omni for the fig 8.

Do do what you are suggesting would require 4 mics and a physically impossible placement to record blumlien.

JAson

[bhtoque]

as cool as that looks, it's not really fig 8's or blumlien.

First, the 8 shape is not oriented in space like you are looking at the 8's on the screen.
Second the lobes of the fig 8 pattern are not 2 circles touching like the number 8, but more like two teardrop shapes touching at the points.

I can't find a good pic online, but from the top down a blumlien setup looks more like a clover.

JAson

[bhtoque]

I realize what blumlein is. just funning with it.

I had a feeling I was missing some sarcasm somewhere, but somebody built that thing with that in mind for sure.

JAson

[bhtoque]

It still comes down to the difference between the two circles of an omni's pick up pattern and the greatly rolled off sides of a fig 8 diaphragm.

With an omni nothing is really off axis, with the fig 8 almost everything is.

Yes, you could put 2 omnis right next to eachother and reverse phase on one, but they would do more to cancel eachother out than compliment eachother.

JAson

[bhtoque]

what took me so long?,.....

baffle 'em

I guess if you were to use a small baffle you could approximate the results of blumlien.

a + shaped baffle with omni's in the corners could work. the top(really front) left and bottom right(out of phase) would make your left channel and the top right and bottom left (out of phase) would make the right. Of course you'd need a 4 ch mixer and a way to invert phase on the 2 back mics. I'd also have to think that the pairs constituting right and left would need to be very closely (amost identicaly) matched.

I sure don't have the hardware to test this out, but it would be interesting to try.

JAson

[poorlyconditioned]

As I recall, he said it worked, and didn't totally suck. But, yeah, its just a bunch of omnis.
want do you want for $8 in cheap capsules?

It is a bunch of cardioids.  Two opposing cardioids (phase-reversed, one +, one -) should give a figure eight pattern.
I don't know the theory (does anyone know the physics to explain why mics have a cardioid shape?), but it looks nice, and other micbuilders claim it works.

By the way, I would beg to differ about the single diaphram.  If you look at famous multipatter mics, like the AKG 414, you'll see two capsules.

  Richard

[bhtoque]

cards,... that makes more sense!
I haven't reviewed that article that supports that pic since, «  on: August 07, 2003, 12:48:57 PM »

that makes more sense to me. I can picture it in my head now. With 2 cards back to back, the "front" of the card patterns would cancel out and the rear lobes would combine to give the 8.

Thanks.

JAson

[it-goes-to-eleven]

I like the baffle idea for omnis!  The best part - it is easy to flip the phase of an existing recording to hear what you'd get.   Wow Moke, you must be excited.  A whole new baffle recording technique to explore!

My initial plan with this wasn't to go straight to blumlein. I was thinking of using it to explore M+S first, especially for situations where I'm dealing with a mono PA.  In one venue I regularly record at, the PA consists of a pair of JBL cabinets centered over the stage.

I had wondered about doing it with cards but I figured there would be more weird 'card effects' (unless good caps are used).

If I try this, I plan on soldering up an adapter to reverse phase and probably another to join two mics. Though providing enough phantom for two mics with one connection could be a problem..

I don't claim to know anything about the tradeoffs between dual vs. single diaphragm fig 8 caps. I just noticed that schoeps and neumann were both fluffing the single dia approach.

[1st set only]

cards,... that makes more sense!
I haven't reviewed that article that supports that pic since, «  on: August 07, 2003, 12:48:57 PM »

that makes more sense to me. I can picture it in my head now. With 2 cards back to back, the "front" of the card patterns would cancel out and the rear lobes would combine to give the 8.

Thanks.

JAson

yes but what is the point? wouldnt this be the equivilent to a out of phase stereo image?
woudnt you have to mix to mono and have another 2 sets of mics inverted the same way to get a proper stereo image?

[SonicSound]

To technical......

Blumlein & Belly Dancer



 

[SonicSound]

thats a lot of foot shuffling noise!

I recorded a concert that was every variation of Romeo and Juliet known in the music/drama world.
There is one version where I had guys-in-tights and puffy shirts, sword fighting directly in front of my stage-lip HRTF head. Lots of foots shuffling, and swords clashing. an interesting listen.

Actually these ladies were barefooted and graceful - no noise just drooling

[SonicSound]

looks like she has sandals on,... :shrugs:
The persian concerts that I record have an extraordinary amount of gorgeous women. stunningly beautiful.

Oops I was not looking at her feet