The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Earthworks ORTF -- in action! Condenser Microphones
Old 4th June 2006
  #31
And you all FELL for it!
Old 4th June 2006
  #32
Quote:
Originally Posted by David Spearritt
So the original post in this thread with picture, while calling it ORTF, is in fact no-where near it.
So shoot me, please.
Old 4th June 2006
  #33
Lives for gear
 
sonare's Avatar
That would require the mics to be on-axis.

BAM BAM (A-B?)

Rich
Old 4th June 2006
  #34
I got all the cool BDSM hardware right off the shelves of the local hardware store-- I live in a very hip town.
Old 4th June 2006
  #35
Lives for gear
 
Plush's Avatar
To clarify:

When one uses omni mics in an arrangement that is designed to use directional mics,
one removes the time of arrival cues that the technique depends on. The closely spaced omni's hear basically the same thing at the same time.

When you use closely spaced omni's, you also have removed the intensity differences (level) that make A-B technique work (because they are, essentially, hearing the same thing.)

So you have removed BOTH of the essentials that give a good stereo picture.

As to the advice given to the previous poster by Earthworks themselves---one would have to refer to my listings in a different thread. In face to face conversations with the designer, Mr. Blackmer, the younger, I refrained from correcting his nonsense knowledge of the mics in order to prevent embarassment. How gentlemanly!

p.s.--but you know what??--if sound is useable for the situation--right on and enjoy the theoretically counterintuitive sound.
Old 4th June 2006
  #36
Gear Head
 

Quote:
Originally Posted by Plush
... one removes the time of arrival cues that the technique depends on. ... you also have removed the intensity differences (level) that make A-B technique
I'm not sure I follow. I would have thought that the following was closer to what one might expect. Most omnis are gradually more directional towards higher frequencies. So it does make sense to point them in some direction. For higher frequencies omnis set up ORTF-like will therefor provide intensity differences between channels from directionality. 17 cm apart corresponds to the wavelength of about 2kHz. We can detect phase differences of about 1/4 wavelength. So even if the omnis are perfect omnis there will be detectable phase differences from about 0,5 kHz and above. Consequently there will be both intensity and phase differences when setting up ordinary omni mics ORTF-like. Not equivalent to cardioids, but still differences in both phase and intensity. Is this not so?

best regards
Lars
Old 4th June 2006
  #37
Lives for gear
 
pkautzsch's Avatar
 

I completely agree about the discussed setup not being "good" from a scientific/theoretic point of view. I also completely agree about the "if it sounds good, it is good" rule.
But I still don't understand:
Quote:
Originally Posted by Plush
When you use closely spaced omni's, you also have removed the intensity differences (level) that make A-B technique work (because they are, essentially, hearing the same thing.)
It is not level differences that make AB work, and not at all intensity differences.
In spaced (A-B) setups, both mics hear basically the same, especially when it's omnis. The only difference is *when* they hear it. The whole thing works only by time differences. These are not touched when changing the directivity of the mics. Level differences occur only when the sound source is quite close to the mics but not in typical setups in front of an orchestra. (If someone is thinking about drum OHs: In typical drum OH setups the source is usually a lot closer to the mic than the mics to each other, so it's rather a poly-miking approach where indeed the level differences are the more important part of the setup.)

In a 17 cm setup, there is still a maximum time difference of about 0.5 ms, that would give something like +-30% width (when 100% is localisation from one speaker only). To get the full width, additional level differences of about 10 dB are needed, and this is achieved by using angled directional mics. By using omnis instead, this *level* difference is removed. But as long as the spacing is the same, the *time* difference is the same as well. The sound doesn't know what kind of mic there is, so it can't change its speed, can it. And even if the sound knew, it still couldn't change its speed because of physics.
In XY setups you don't have time differences, have you? Yet you have directional mics.

One of us is wrong. And I'm sorry to have to say that I think it's not me.
Old 4th June 2006
  #38
Lives for gear
 

Quote:
Originally Posted by Plush
To clarify:

When one uses omni mics in an arrangement that is designed to use directional mics,
one removes the time of arrival cues that the technique depends on. The closely spaced omni's hear basically the same thing at the same time.

When you use closely spaced omni's, you also have removed the intensity differences (level) that make A-B technique work (because they are, essentially, hearing the same thing.)

So you have removed BOTH of the essentials that give a good stereo picture.
I think you have it a bit confused Plushy. Spacing mics relies on time of arrival or phase differences to locate the image. Sound from the side reaches one mic first then the other. With omnis, this is the only differentiator for image, since both mics receive the same SPL (assuming negligable distance attentuation), due to uniform directivity.

With any directional mics, intensity differences or different SPL produces the image shifting, when sound arrives from the side the near side mic picks up higher SPL than the far mic since the far mic is more off axis and therefore down in directivity and intensity.

Combining these two effects gives us a wonderful combination to play with. Spaced omnis can only rely on time of arrival cues as intensity cues are gone, coincident cards or Blumlein can only rely on intensity differences as there is no time of arrival differences.
Old 4th June 2006
  #39
Seems like what we may have with this arrangement is a recording that has elements of ORTF in the higher frequencies where the omnis become slightly directional, transitioning smoothly to mono as you go lower in frequency. At the frequencies where the omnis are essentially omni you have a narrow spaced pair with head width spacing which would give a binaural effect on headphones.
I understand that spacing omnis gives the sensation of space through some kind of phase confusion process.
A simple test reveals the accuracy of image placement of various stereo techniques: set up the array (say in front of a stage) and walk in an arc equidistant from the microphones from left to right. With an "ideal" arrangement, on speaker playback of course the result should be what you would expect. It seems that with most, the results are very different from this, typically a "wandering around" sensation in the general area of the left speaker with a sense of unspecific movement, followed by a sudden shift to the right with a similar wandering effect there. Only Blumlein captures the process accurately. I have done this experiment with ORTF and spaced omnis, not Decca tree, and Blumlein (Speiden SF12, like the Royer equivalent) and the differences were profound. I've used the SF12s as main pickup ever since and add "space" when needed with reverb or distant room mics.
Old 5th June 2006
  #40
Lives for gear
 
Plush's Avatar
No, I hardly feel that I'm confused. Time of arrival in this set-up is not different enough to project a credible stereo picture. Level is also not different enough. That is the point.

Also, there is no binaural effect here because there is no barrier between the mics---and no ear pinnae.

Why do you all assume that the omni mic is *substantially* more directional in higher freqs.?

Basically, what I am arguing for is more space between the omni mics in the original photograph.
Old 5th June 2006
  #41
Lives for gear
 
sonare's Avatar
Guys, take a deep breath! Remember what the Duke said.

"If it SOUNDS good it IS good."

Does the setup sound good?

Rich
Old 5th June 2006
  #42
Lives for gear
 

Just to reiterate: the setup has nothing to do with ORTF. Not same mics, not same distance. If anything it looks more like DIN. IF it had been cardioids that is.

This is simply AB or spaced omnis. Which in my world is a bl**dy good way of making recordings. Depending on the room and a lot of other things of course.

AB or spaced omni setups seem to come in two flavours. It is almost like two schools. Perhaps it is an American school and a European school, I cannot really say.

One school puts the two omnis rather far from each other. Say 6 feet and upwards (about 2 meters for the rest of us).

The other school puts the omnis rather close. Say less than 60 centimeters or so (about two feet).

Both schools get good sound with nice stereo effect. They probably place the mics a bit closer or farther off though.

Personally I tend to put a pair of DPA 4003 at about 50 centimeters apart and add a pair of outriggers.

Gunnar
Old 5th June 2006
  #43
Lives for gear
 
sonare's Avatar
There are additional factors involved in spacing-- namely the acoustic and size of the ensemble. All of which led me to the Jecklin disc for many situations. Excellent imaging with omni sound-- the best of both worlds, but NOT for everything! (Piano, for instance.)

Rich
Old 5th June 2006
  #44
Super Moderator
 
Remoteness's Avatar
Rich,

Why don't you like it for piano?
Old 5th June 2006
  #45
Lives for gear
 
sonare's Avatar
I did not say I don't like them for piano! And what piano are you talikign about? Jazz? Pop? Classical? Steinway D? Hamburg Steinway? Yamaha? Bosendorfer? With extension? Baldwin?

Follow the Duke! (If it SOUNDS good, it IS good!)

Rich
Old 5th June 2006
  #46
Gear Addict
 

a very confused/confusing thread this is !

Hans
Old 5th June 2006
  #47


Well, I have to disagree with Plush. Humans do, indeed, locate sound using phase differences below about 1kHz.

Below about 500Hz, the difraction around the head makes it acoustically invisible. So, spaced omni's with no disk/dummy-head/HRTF-blob between them will provide good stereo image at lower frequencies (through headphones anyway).




-tINY

Old 5th June 2006
  #48
Lives for gear
 
sonare's Avatar
While my reply above still applies, I missed the Jecklin-for-piano part. I do not like it on piano because it is not like listening to a "classical" piano in concert, which is rather "amorphous."

IOW the Jecklin is too accurate in most cases. Could be just the thing for the Goldberg Variations or such.

Rich
Old 5th June 2006
  #49
Lives for gear
 
T.RayBullard's Avatar
 

Quote:
One of us is wrong. And I'm sorry to have to say that I think it's not me.
That sounded pretty obnoxious, Peter. Plush has been in the business for a quarter of a century, and learned his craft from one of the greatest classical recording masters alive...those with less than 15 years or even 10 years experience would do well to pay attention to what he has to say..Myself included.

I hear all these scientific theories and acoustic dissertation...and that is all fine and good, but I value his experience more than entire volume of "theory".. I like the way he (Plush, and others like SonareRec, and Steve Remote)communicates because he doesn't use fancy words or quote acoustic engineering journals.. Just give basic answers that use this thing called common sense. (Which is developed not in a classroom or with a nose in a book, but through time , failure,success, and most importantly, HUMILITY.. The ability to swallow pride, admit that science is just man's(man=flawed last I checked) best guess at any point in time, and listen to those that have earned their stripes in the trenches.)

Science and music are not good bedfellows. Id rather hear a good story from someone like him than hear "well,


.." and then I went to my main pair (spaced exactly 32.3333 centimeters apart to avoid phase anomolies then I also calculated wind difference and heat based on the average age of the audience and to avoid mid range smear and here are some samples.


Over and out.
Old 5th June 2006
  #50
Lives for gear
 
pkautzsch's Avatar
 

Quote:
Originally Posted by Plush
Time of arrival in this set-up is not different enough to project a credible stereo picture.
Ah, now I see what you mean. Didn't quite understand it that way before: I thought you meant that changing the pattern affects the time difference (which it does not).
As I wrote, 17 cm can work fine for solo instruments/vocalists where we don't want the source but only the space around it to appear wide. Great as jazz OH, for example. But will never work as a main mic for an orchestra which we want to spread from one speaker to the other.
Old 5th June 2006
  #51
Gear Head
 

Quote:
Originally Posted by T.RayBullard
Science and music are not good bedfellows.
To me that sounds like neither performing nor recording music requires knowledge or understanding. You can't really mean that, can you? Knowledge and understanding is what science is about...

best regards
Lars
Old 5th June 2006
  #52
Lives for gear
 
T.RayBullard's Avatar
 

Quote:
Originally Posted by larsfarm
To me that sounds like neither performing nor recording music requires knowledge or understanding. You can't really mean that, can you? Knowledge and understanding is what science is about...

best regards
Lars
let me rephrase. Sometimes technical knowledge and book-smarts dont amount to much in this gig, in my experience. Common sense and willingness to deviate from the "norm" have been way more valuable to me. If that makes any sense.
Old 5th June 2006
  #53
Lives for gear
 
pkautzsch's Avatar
 

Quote:
Originally Posted by T.RayBullard
That sounded pretty obnoxious, Peter.
Wasn't at all meant that way! If I have been impolite, I very much apologize.
The whole thing turned out to be a great misunderstanding...actually we had the same point (ie. 17 cm is not enough for full stereo width, but if it sounds good it is good).

As to scientific-only vs listening-only approaches: I'm not a scientific-only guy. Not at all. I don't think I understand the details of much of the scientific theory. And I don't really like people who rely on formulas only and use them as a super-weapon against everything non-formulaic (I think that music has to do a lot with taste&emotion and thus can't be handled by using only formulas). But I have found that knowing just the basics like that 1.5 ms thing can help a lot to get the rough setup that actually gives the sound and image I have in my head. I started without that knowledge (and sometimes also without an image in my head) and don't really like those recordings now.
Old 5th June 2006
  #54
Lives for gear
 
mosrite's Avatar
 

So how about these Earthworks QTC30's then? are they good at anything other than sparking fierce debate?
Old 5th June 2006
  #55
Lives for gear
 

Forgive me for saying this, but this thread is a classic example of why its important that we are talking with the same, accurate terminology. Its not scientific jargon, its simple terminology. If you meant oranges, there's no point in calling them apples and then getting upset when, (a) you get corrected, or (b) people cannot understand.

ORTF is well specified, defined and understood, as is time difference and intensity difference cues for stereo imaging. Its not being buried in scientific jargon, its just getting the words right. I think everyone meant the same thing in the end.
Old 5th June 2006
  #56
Gear Addict
 

Quote:
Originally Posted by David Spearritt
Forgive me foe saying this, but this thread is a classic example of why its important that we are talking with the same, accurate terminology. Its not scientific jargon, its simple terminology. If you mean oranges, there's no point in calling them apples and then getting upset when, (a) you get corrected, or (b) people cannot understand.

ORTF is well specified, defined and understood, as is time difference and intensity difference cues for stereo imaging. Its not being buried in scientific jargon, its just getting the words right.
Well said !

H
Old 6th June 2006
  #57
Lives for gear
 
T.RayBullard's Avatar
 

Forgive my haste. Sometimes translation over the interweb is not what we wish it to be. My apologies.

Quote:
Originally Posted by pkautzsch
Wasn't at all meant that way! If I have been impolite, I very much apologize.
The whole thing turned out to be a great misunderstanding...actually we had the same point (ie. 17 cm is not enough for full stereo width, but if it sounds good it is good).

As to scientific-only vs listening-only approaches: I'm not a scientific-only guy. Not at all. I don't think I understand the details of much of the scientific theory. And I don't really like people who rely on formulas only and use them as a super-weapon against everything non-formulaic (I think that music has to do a lot with taste&emotion and thus can't be handled by using only formulas). But I have found that knowing just the basics like that 1.5 ms thing can help a lot to get the rough setup that actually gives the sound and image I have in my head. I started without that knowledge (and sometimes also without an image in my head) and don't really like those recordings now.
Old 6th June 2006
  #58
Lives for gear
 
pkautzsch's Avatar
 

YOU weren't hasty, Teddy

I was.

Quote:
Sometimes translation over the interweb is not what we wish it to be
Writing a thesis about this phenomenon right now, for that day job one might need. It is really *very* interesting how easily utterances can be misunderstood.
Old 6th June 2006
  #59
Lives for gear
 
T.RayBullard's Avatar
 

This thread will provide some fine material for that paper, Peter. . I look forward to the day when recording is my day job instead of supplementary income. Good luck with the paper! I think language barriers are a big part of it too..nuances are often lost in translation. I know that from being an Alien here in your country. Getting better though.


Quote:
Originally Posted by pkautzsch
I was.


Writing a thesis about this phenomenon right now, for that day job one might need. It is really *very* interesting how easily utterances can be misunderstood.
Old 6th June 2006
  #60
Lives for gear
 
pkautzsch's Avatar
 

Now this is getting off-topic, sorry for that. Can't use these great examples because I'm involved in the thread, and thus theoretically could produce whatever proof I like.
/off-topic

Back to topic: It just came to my mind that when set up close to the source there actually are level differences even between closely spaced omnis. In this case, such a setup becomes "equivalent" like ORTF; in theory a source 17 cm to the right of a 17 cm spaced omni setup should be 6dB lower at the left mic than at the right (resulting in another like 30%, together with .5 ms this would give about 60%). But when do we have a setup that close to a source.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
stellar / Remote Possibilities in Acoustic Music and Location Recording
8
tamasdragon / Remote Possibilities in Acoustic Music and Location Recording
3
structuredloud / Remote Possibilities in Acoustic Music and Location Recording
3
Dr Funk / Remote Possibilities in Acoustic Music and Location Recording
10
Jules / Remote Possibilities in Acoustic Music and Location Recording
18

Forum Jump
Forum Jump