You are here

Coincident stereo with subcardioids

All about the tools and techniques involved in capturing sound, in the studio or on location.

Coincident stereo with subcardioids

Postby Ron Snijders » Tue Jun 18, 2013 12:06 pm

Apologies beforehand if this is a really stupid question. I've Googled a bit, but I can't seem to be able to find any real answer to this question (I guess subcards aren't as widely used as cards or omnis).
As I'm a beginner in the whole recording field, I'm currently building my mic collection. I recently had a chance to pick up a pair of Neumann KM143s at a very good price. Those mics being subcardioids does, however, limit the amount of documentation regarding their uses that I can find. I guess they'll do perfectly fine as a spaced array, but what about coincident or near-coincident? Should I simply angle them more than I would with cardioids to get them more off-axis to eachother, will they work just like cards, but with a smaller stereo spread, or is the concept flawed from the beginning, and should I pick up a pair of KM183s, or perhaps the cardioid capsules for the KM100 series?

Thanks in advance for any answers! :)
User avatar
Ron Snijders
Regular
Posts: 113
Joined: Sun Sep 02, 2012 11:00 pm

Re: Coincident stereo with subcardioids

Postby John Willett » Tue Jun 18, 2013 12:27 pm

Sub-cardioids (hypo-cardioids or wide-cardioids) are an excellent pattern and are very useful.

Though I would not use them in a co-incident array, they are fine when spaced. Not necessarily widely spaced (though that is also possible), but I would get them apart by about head width as a minimum.
User avatar
John Willett
Jedi Poster
Posts: 4217
Joined: Tue Mar 07, 2000 12:00 am
Location: Oxfordshire UK

John
Sound-Link ProAudio
Circle Sound Services
President - Federation Internationale des Chasseurs de Sons


Re: Coincident stereo with subcardioids

Postby Hugh Robjohns » Tue Jun 18, 2013 1:18 pm

Ron Snijders wrote:I guess they'll do perfectly fine as a spaced array, but what about coincident or near-coincident?

You can't use hypo-cardioids in a coincident array, at all, because you don't get any stereo image!

The reason is that coincident arrays rely on level differences between the mics to create the stereo image, and those level differences come from the combination of polar pattern and mutual angle. With coincident hypo-cardioids you can't generate sufficient level difference to capture a useful stereo image, regardless of the mutual angle.

There are some useful charts in this PDF article that illustrate the stereo acceptance angles obtained with different polar patterns at different mutual angles and spacings. Check out figure 4!

With hypo-cardioids you can only work with near or wide spacing. For example, if you set up hypo-cardioids like an ORTF pair -- 17cm spacing and 90 degree mutual angle -- then you will have a stereo acceptance angle of around +/-80 degrees, which is useful.

H
User avatar
Hugh Robjohns
Moderator
Posts: 17521
Joined: Thu Jul 24, 2003 11:00 pm
Location: Worcestershire, UK

Technical Editor, Sound On Sound


Re: Coincident stereo with subcardioids

Postby Ron Snijders » Tue Jun 18, 2013 3:26 pm

Thanks for the helpful replies! I was thinking that by exaggerating the mutual angle, I might be able to coax some stereo image from them, but it appears that that was a misguided idea.

The reason I'm asking is that I'd like to record a relatively small instrument, like a hang drum, on its own and still get a filled stereo image, without getting too distant (because the hang has a very 'reverby' sound of its own, I think recording too far away might drown it too much, not to mention that I don't have access to a proper room for that). I guess I'll have to go with a near-coincident or spaced array then. I hadn't really thought of the relatively small capsule distance needed to get a decent stereo image, so I was worried that I would have mics pointing past the drum.
User avatar
Ron Snijders
Regular
Posts: 113
Joined: Sun Sep 02, 2012 11:00 pm

Re: Coincident stereo with subcardioids

Postby The Korff » Tue Jun 18, 2013 3:34 pm

Try pointing two directional mics over the player's shoulders? I did that on hang drums live once on a massive stage, it worked a treat.

Cheers!

Chris
The Korff
Frequent Poster
Posts: 1780
Joined: Fri Jan 08, 2010 11:28 am
Location: The Wrong Precinct

I AM KORFF



Who is online

Users browsing this forum: No registered users and 6 guests