You are here

Figure of 8 as Mid in Mid/Side

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

Figure of 8 as Mid in Mid/Side

Postby Bob Bickerton » Wed Jan 11, 2017 11:07 am

A post beer curiosity ramble.....

We've discussed a number of times the usefulness of using two figure of eight mics for recording singer guitarists, pointing the null of the pattern at the opposite source to attenuate it.

Recently I've been experimenting with M/S recording on instruments like guitar and have been well pleased with the results from using an MKH8040/MKH30 combo.

So I've been thinking that it may be useful to use an M/S technique when recording singer guitarists. The theory being that if the mid mic was figure of eight with the null pointing at the voice then the side mic would, by default, have it's null pointing at the voice as well.

I've just tried it with a Naked Eye ribbon as the mid and the MKH30 as the side and using a U87 on the voice. Plenty of attenuation of opposite sources, but I'm finding the guitar sounds pretty phasey when the side is kicked in.

Haven't spent much time on it and really just messing around, but I was curious to know if this was a recognised technique and if it's workable.

Bob
User avatar
Bob Bickerton
Frequent Poster
Posts: 3138
Joined: Fri Dec 20, 2002 12:00 am
Location: Nelson, New Zealand
http://www.bickerton.co.nz

Re: Figure of 8 as Mid in Mid/Side

Postby John Willett » Wed Jan 11, 2017 12:59 pm

Hi Bob,

Two fig-8 in MS is the way Blumline originally did it.

Read this paper by Wes Dooley and Ron Streicher which will explain it all (link is to a PDF).

But the mid fig-8 points towards the voice - only the side has the null to the voice.

The paper includes some very good diagrams which show what happens with various level differences between the mid and side mics - excellent. :thumbup:

Some of the nasties you hear may be due to having a switchable-pattern mic. in fig-8, rather than using a second MKH 30.

I hope this helps.
User avatar
John Willett
Jedi Poster
Posts: 4442
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: Figure of 8 as Mid in Mid/Side

Postby Bob Bickerton » Wed Jan 11, 2017 7:58 pm

Thanks John.

I probably wasn't clear, but was talking about an M/S array on guitar PLUS a figure of eight on voice.

Bob
User avatar
Bob Bickerton
Frequent Poster
Posts: 3138
Joined: Fri Dec 20, 2002 12:00 am
Location: Nelson, New Zealand
http://www.bickerton.co.nz

Re: Figure of 8 as Mid in Mid/Side

Postby Sam Inglis » Wed Jan 11, 2017 8:10 pm

I wonder if the problem here is that the Sides mic on the guitar is basically off-axis to everything. So, although the vocal is in the deepest part of the null, actually the guitar is also in the side null. I'd imagine the separation in the Sides mic is not as good as it is in the Mid mic, and that any vocal it does capture is fairly nasty.

For me this is a situation where you're nearly always better off with the more artificial stereo picture you get from two separate guitar mics in different places, both positioned so the guitar is on-axis and the vocal in the null.

In theory the M/S approach might offer a more 'realistic' picture of the guitar, but then who listens to guitars from a foot in front of the neck joint anyway?
Sam Inglis
Frequent Poster
Posts: 2115
Joined: Fri Dec 15, 2000 12:00 am

Re: Figure of 8 as Mid in Mid/Side

Postby Kwackman » Wed Jan 11, 2017 8:13 pm

Bob Bickerton wrote: I'm finding the guitar sounds pretty phasey when the side is kicked in.

How close to each other were the Mid & Side capsules?
If you zoom in to waveform level, can you see if the two mic tracks are totally in phase?

Last year, thanks to a discussion you & the Elf had, I experimented with MS recording of an acoustic guitar. I hadn't the capsules terribly close together, and delaying the M mic track (or advancing the S mic track) to make the waveforms match up, helped get rid of some oddities I was having.
I discovered (2nd recording) that making a sync "clap" before playing the tune, makes aligning tracks so much easier!
The above may, or may not be relevant to your situation..
User avatar
Kwackman
Frequent Poster
Posts: 872
Joined: Thu Nov 07, 2002 12:00 am
Location: Belfast
Cubase, guitars.

Re: Figure of 8 as Mid in Mid/Side

Postby Hugh Robjohns » Wed Jan 11, 2017 8:57 pm

Bob Bickerton wrote:I've just tried it with a Naked Eye ribbon as the mid and the MKH30 as the side and using a U87 on the voice. Plenty of attention of opposite sources, but I'm finding the guitar sounds pretty phasey when the side is kicked in.

So the idea of using fig 8s on voice and guitar, angled so that their nulls reject the opposite source, is an established technique (and one I described in SOS nearly 20 years ago!)

The idea of using an MS array to record acoustic guitars is also well known and, as you say, the side mic null can be angled towards the voice very easily too.

The MS array on its own shouldn't sound phasey, because it's a coincident array. Of course... If the capsules aren't tightly coincident anything is possible...

But if it sounds phasey when you fade up the side mic with the vocal mic (U87) is because they are both hearing the same thing, separated by a short time delay.

So, either the side mic null isn't rejecting enough of the voice (picking up chest resonances, maybe), or it's picking up vocal sound reflected off the walls/floor/guitar body etc.

H
User avatar
Hugh Robjohns
Moderator
Posts: 18421
Joined: Thu Jul 24, 2003 11:00 pm
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Figure of 8 as Mid in Mid/Side

Postby Jadoube » Wed Jan 18, 2017 6:33 pm

Sam Inglis wrote:In theory the M/S approach might offer a more 'realistic' picture of the guitar, but then who listens to guitars from a foot in front of the neck joint anyway?

From my own experiments with a similar thing using a Crown PZM Stereo "Head" (SASS-P I think... been a while.), it always got down to "interesting sound" but... nope. Too weird. Difficult to control the image with a vocal in there.

Hugh Robjohns wrote:So, either the side mic null isn't rejecting enough of the voice (picking up chest resonances, maybe), or it's picking up vocal sound reflected off the walls/floor/guitar body etc.

I would be more inclined to back the stereo mic off a bit (a lot) and record the whole performance plus the details mics. Control the ambience, And hope your artist doesn't move much! :-) It's great fun to play around with it though. As I recall, the stereo head thing was really stable for this sort of thing. I've less experience with M/S configurations, so I'm not sure how it compares. I would use the Stereo head on guitar + Figure 8 on voice null pointing at guitar. I don't think any of those tracks ever made the cut when it was all said and done... for reasons of the first point; too weird. The artists were very traditional so it just wasn't appropriate. A trick I use now is to mix in a subtle bit of direct signal with the UAD Acoustic Guitar modelling plugin. Can be very stereo.

I need to play around with M/S more...
User avatar
Jadoube
Regular
Posts: 248
Joined: Mon May 12, 2003 11:00 pm
Location: Calgary, Canada
David

Re: Figure of 8 as Mid in Mid/Side

Postby awjoe » Thu Jan 19, 2017 1:54 am

Bob Bickerton wrote:
So I've been thinking that it may be useful to use an M/S technique when recording singer guitarists. The theory being that if the mid mic was figure of eight with the null pointing at the voice then the side mic would, by default, have it's null pointing at the voice as well.

Bob

I'll try it as soon as I get back from vacation, but I would have thought the third mic added extra information to an unhelpful degree.

The problem I'm working with using two coincident figure 8's for singing/playing is proximity effect on the vocal. I probably just need a new mic, but I can't afford that right now, so my next experiment is going to be shifting the performer's chair 4" further from the mics. More spill, but maybe worth the trade-off. (And if that doesn't work, then I'll be playing around with a Faulkner array next...).

How does distance from the mics factor in to your 3-mic experiment?
User avatar
awjoe
Frequent Poster
Posts: 2068
Joined: Tue Mar 08, 2011 12:00 am
"Against stupidity we are defenseless."  - ascribed to poor old Dietrich Bonhoeffer, who felt defenseless against stupidity

Re: Figure of 8 as Mid in Mid/Side

Postby Bob Bickerton » Thu Jan 19, 2017 9:10 am

Sorry I have not updated this but the studio has been out of action while I produce a Festival.

There was more vocal bleed in the guitar mics than I would have liked and I suspect that was the problem, or at least a factor in it.

Bob
User avatar
Bob Bickerton
Frequent Poster
Posts: 3138
Joined: Fri Dec 20, 2002 12:00 am
Location: Nelson, New Zealand
http://www.bickerton.co.nz


Who is online

Users browsing this forum: Ariosto, Jay Menon, mashedmitten and 5 guests