Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.pro
Nate Najar Nate Najar is offline
external usenet poster
 
Posts: 594
Default ortf question

hypothetically speaking of course, if you were to do ortf with a pair of mk41's, about how far apart should the capsules be?

with cardioid I do my best to get them at 110 degrees and they end up around 6.5" apart. with the supercardioids, at 90 degrees, how far?

thanks!
  #2   Report Post  
Posted to rec.audio.pro
Arny Krueger[_4_] Arny Krueger[_4_] is offline
external usenet poster
 
Posts: 854
Default ortf question


"Nate Najar" wrote in message
news:24517183.675.1323786885166.JavaMail.geo-discussion-forums@yqlh5...
hypothetically speaking of course, if you were to do ortf with a pair of
mk41's, about how far apart should the capsules be?

with cardioid I do my best to get them at 110 degrees and they end up
around 6.5" apart. with the supercardioids, at 90 degrees, how far?


What parts of the mics are 6.5 inches apart? I am generally able to get
the diaphragms of small diameter mics within a fraction of an inch of
touching at the edges. I've even done it with vocal mics by screwing off the
balls.


  #3   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default ortf question

Nate Najar wrote:
hypothetically speaking of course, if you were to do ortf with a pair of mk41's, about how far apart should the capsules be?


If you are recording ORTF, you are using two mikes at 110 degrees with
20 cm spacing. If you are using anything else, you are not using ORTF.

with cardioid I do my best to get them at 110 degrees and they end up around 6.5" apart. with the supercardioids, at 90 degrees, how far?


If you want to try other non-ORTF near-coincident cardioid configurations,
go ahead. The more you space them apart, the wider the stereo field at low
frequencies will be. The greater the angle, the wider the stereo field at
high frequencies will be UNTIL you get to a certain point at which the stereo
field starts shrinking as you move them farther out.

What configuration is optimal has more to do with the room than the mikes.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #4   Report Post  
Posted to rec.audio.pro
PStamler PStamler is offline
external usenet poster
 
Posts: 882
Default ortf question

On Dec 13, 10:20*am, (Scott Dorsey) wrote:
Nate Najar wrote:

hypothetically speaking of course, if you were to do ortf with a pair of mk41's, about how far apart should the capsules be?


If you are recording ORTF, you are using two mikes at 110 degrees with
20 cm spacing. *If you are using anything else, you are not using ORTF.


Scott's right; to be Real ORTF, 110 degrees and 20cm. But Pseudo ORTF,
with hypercardioids, 90 degrees and 20cm, works just fine.

Peace,
Paul
  #5   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default ortf question

PStamler wrote:

On Dec 13, 10:20*am, (Scott Dorsey) wrote:
Nate Najar wrote:

hypothetically speaking of course, if you were to do ortf with a pair of mk41's, about how far apart should the capsules be?


If you are recording ORTF, you are using two mikes at 110 degrees with
20 cm spacing. *If you are using anything else, you are not using ORTF.


Scott's right; to be Real ORTF, 110 degrees and 20cm. But Pseudo ORTF,
with hypercardioids, 90 degrees and 20cm, works just fine.

Peace,
Paul


I hate to nitpick with Scott and Paul but the ORTF spacing is actually 17cm.
Maybe something went astray in the double translation: cm inches cm :-)

Nate, it really depends on how one defines "same as ORTF''.
Is it the same SRA? (Stereophonic Recording Angle - ˙ou could think of that as
the arc that the performers have to be fitted within to ensure a smooth recorded
image spread, with no bunching of the outermost side flank players in the L and
R speakers.). Or do you want close matching of other parameters such as the
Angular Distortion of the images? etc. etc.

You could may wish to check out the following stereo image visualization tool:

http://www.sengpielaudio.com/Visualization-EBS.htm

This shows an ORTF array to have an SRA of +/- 48 deg - which would be
approximated by a Hypercardioid array of 90 deg. / 13.5cm. Other angle-spacing
combinations are of course possible.

However, the polar response equation for the hypercardioid employed in this
model was not stated (typcally " 0.25 + 0.75.cos(theta)". And there was no
possibility to run the visualization with a Supercardioid such as your Mk41
(with its wider polar response of perhaps " 0.37 + 0.63.cos(theta)").
--
Tom McCreadie

Live at The London Palindrome - ABBA


  #6   Report Post  
Posted to rec.audio.pro
PStamler PStamler is offline
external usenet poster
 
Posts: 882
Default ortf question

On Dec 13, 8:15*pm, Tom McCreadie wrote:
Scott's right; to be Real ORTF, 110 degrees and 20cm. But Pseudo ORTF,
with hypercardioids, 90 degrees and 20cm, works just fine.


Peace,
Paul


I hate to nitpick with Scott and Paul but the ORTF spacing is actually 17cm.
Maybe something went astray in the double translation: *cm inches cm * :-)


Whoops -- right you are. And wrong we were.

Is it NOS that's 20cm?

Peace,
Paul
  #7   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default ortf question

PStamler wrote:

Is it NOS that's 20cm?

Peace,
Paul


NOS is 30cm

Pattern / spacing / angling of some stereo arrays::
NOS cardioid / 30cm / 90 deg.
DIN cardioid / 20cm / 90 deg.
DINa cardioid / 17cm / 90 deg.
ORTF cardioid / 17cm / 110 deg
Faulkner Fig-8./ 20cm / 0 deg. (i.e. parallel, forward)

Some useful info on the dpa site
http://www.dpamicrophones.com/en/Mic...echniques.aspx

One can't expect to fully emulate an ORTF result using mics of other polar
patterns...for even if one could juggle the angling and spacing to get the
imaging to be pretty close, the direct to reverberant ratio of room sound would
still differ from that of ORTF..
--
Tom McCreadie
  #8   Report Post  
Posted to rec.audio.pro
ebs ebs is offline
external usenet poster
 
Posts: 1
Default ortf question

On Dec 14, 3:15*am, Tom McCreadie wrote:
PStamler wrote:
On Dec 13, 10:20*am, (Scott Dorsey) wrote:

You could may wish to check out the following stereo image visualization tool:

http://www.sengpielaudio.com/Visualization-EBS.htm

This shows an ORTF array to have an SRA of +/- 48 deg *- which would be
approximated by a Hypercardioid array of 90 deg. / 13.5cm. Other angle-spacing
combinations are of course possible.
However, the polar response equation for the hypercardioid employed in this
model *was not stated (typcally *" 0.25 + 0.75.cos(theta)". *And there was no
possibility to run the visualization with a Supercardioid such as your Mk41
(with its wider polar response of perhaps " 0.37 + 0.63.cos(theta)").


This stereo image visualization tool:
http://www.sengpielaudio.com/Visualization-EBS-E.htm
Shows the microphone polar patterns:
Omnidirectional, Subcardioid, Cardioid, Supercardioid, and
Bidirectional.
The Supercardioid has just the polar equation 0.37 + 0.63 x cos(theta)
like your Schoeps Mk41.

Cheers ebs



  #9   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default ortf question

ebs wrote:

This stereo image visualization tool:
http://www.sengpielaudio.com/Visualization-EBS-E.htm
Shows the microphone polar patterns:
Omnidirectional, Subcardioid, Cardioid, Supercardioid, and
Bidirectional.
The Supercardioid has just the polar equation 0.37 + 0.63 x cos(theta)
like your Schoeps Mk41.

Yes, thanks for correcting my sloppiness.
While writing, I'd made a detour to the Schoeps site to remind myself on whether
the Mk41 was listed as a super- or a hyper...and then apparently returrned from
that late-night trip with my supers and hypers in a twist :-)..
So the tool now becomes a bit more relevant for Nate with his Mk41's.


--
Tom McCreadie

Live at The London Palindrome - ABBA
  #10   Report Post  
Posted to rec.audio.pro
hank alrich hank alrich is offline
external usenet poster
 
Posts: 4,736
Default ortf question

Tom McCreadie wrote:

I hate to nitpick with Scott and Paul but the ORTF spacing is actually 17cm.


Tom, thanks for nitpicking. I'd wager both Scott and Paul can appreciate
it.

--
shut up and play your guitar * http://hankalrich.com/
http://www.youtube.com/walkinaymusic
http://www.sonicbids.com/HankandShaidri


  #11   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default ortf question

hank alrich wrote:
Tom McCreadie wrote:

I hate to nitpick with Scott and Paul but the ORTF spacing is actually 17cm.


Tom, thanks for nitpicking. I'd wager both Scott and Paul can appreciate
it.


Agreed. I think in inches, sadly.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #12   Report Post  
Posted to rec.audio.pro
Ty Ford Ty Ford is offline
external usenet poster
 
Posts: 2,287
Default ortf question

On Tue, 13 Dec 2011 10:17:21 -0500, Arny Krueger wrote
(in article ) :

screwing off the balls.


heh, heh.

Bevis & Butthead

--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA

  #13   Report Post  
Posted to rec.audio.pro
Mike Rivers Mike Rivers is offline
external usenet poster
 
Posts: 8,744
Default ortf question

On 12/13/2011 9:34 AM, Nate Najar wrote:
hypothetically speaking of course, if you were to do ortf with a pair of mk41's, about how far apart should the capsules be?


No need to speak hypothetically. There's an official
definition of the angle and capsule spacing for ORTF by the
French organization that set the standard. I don't remember
what it is, but you can use Google as well as I can.

with cardioid I do my best to get them at 110 degrees and they end up around 6.5" apart.


They can be displaced vertically by an inch or so without
ruining the concept. If what's defining the capsule spacing
at the angle you're using is that the back end of the mics
with the connector and cable are trying to occupy the same
physical space, you can put cobble up something on your
stereo bar to raise one mic so they can overlap at the back
end. Or maybe using right-angle XLR plugs on the mic end of
the cable will give you enough working room. I used the
right angle XLRs with with a pair of Shure SM-81s to get the
official ORTF angle and spacing.

And if that's the spacing and angle that sounds right to
you, who cares what it SHOULD be? You've been doing this
long enough to know what you want it to sound like.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff
  #14   Report Post  
Posted to rec.audio.pro
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default ortf question

Nate Najar wrote:

hypothetically speaking of course, if you were to do ortf with a pair
of mk41's, about how far apart should the capsules be?


with cardioid I do my best to get them at 110 degrees and they end up
around 6.5" apart. with the supercardioids, at 90 degrees, how far?


ORTF is traditionally cardiods at 110 degrees and a certain spacing, I think
it is 17.5 centimeters. Over here we say X-Y whenever we have microphones at
a short distance, from 0 to 25 centimeters between capsules. In the US of A
it is only X-Y if the capsule distance is 0 centimeters. Consequently the
wording ORTF gets used a lot of times when it shouldn't be and the wording
"intensity+time de-correlated" should.

It is all about de-correlation:

intensity decorrelation: coincident stereo, in USA called X-Y, capsule
distance zero.

intensity+time decorrelation: ORTF and similar, in Europe called X-Y,
capsule distance zero (remember zero == coincident) to 30 centimeters.

time decorrelation: A-B, capsule distance typically 30 centimeters to 2
meters, if you are very far from the source the distance can be
increased/needs to be increased.

thanks!


So the answer to your question is that it depends on how far from the sound
source you are. I mostly use an angle between 45 and 80 degrees when using a
standard K&M crossbar. For the ORTF angle of 110 degrees to work well you
have to remove the chais in the middle of row 4,5 and 6 so that you can
place the mic stand there and to me it would sound too distant due to too
much reflected sound anyway and audience noise might be a problem because
not behind the mic pair.

In the real world of live recording you determine which 5 square feet of
real estate you can place the mic stand on and adjusts mic angle and height
to get a good panorama with good tonal balance also for the rearmost guys.
Usually that implies aiming the mics vertically at the rearmost sound
sources. Doing that comes with an image advantage: mic PAIR off-axis
behaviour pulls extreme left and right of front row musicians toward the
center, thus at best changes the usual trapezoid orchestral image to a
rectangular.

Find and read that "Stereophonic Zoom" paper!

Kind regards

Peter Larsen



Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
ortf delay to ortf. do they need to be same configuration?? lewdslewrate Pro Audio 7 April 11th 11 12:55 PM
Quick question ORTF mic angles Richard Corfield Pro Audio 15 February 17th 08 06:52 PM
ORTF vs AB Lars Farm Pro Audio 10 October 24th 05 10:20 PM
ORTF and panning L/R offpeak808 Pro Audio 41 October 3rd 04 12:01 PM
ORTF + Mid? Dave Brown Pro Audio 21 March 15th 04 10:23 AM


All times are GMT +1. The time now is 06:33 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"