On Fri, 30 Mar 2012 08:37:54 -0400, Matt Faunce
wrote:
On 3/30/12 1:25 AM, Don Pearce wrote:
On 29 Mar 2012 22:37:33 -0400, (Scott Dorsey) wrote:
Matt wrote:
A year or so back, I followed a link from here, r.a.p., to a good
article that described why the proximity effect of a cardioid microphone
goes away when the side of the diaphragm is pointed at the sound source
rather than the front, but now I can't find it. The URL was
http://81.174.169.10/odds/mic/ If you know what article I'm talking
about could you tell me if the article has a new URL? Maybe you know or
remember the guy who wrote it.
But... it doesn't. The proximity effect remains no matter what direction
it's pointed in. It has only to do with the pattern of the microphone and
the distance from the source.
In fact, if you turn the microphone to the side so the source is off-axis,
you will lose the high end (since typical cardioid mikes are only cardioid at
higher frequencies and are omni down on the bottom). So the bass boost
seems even more emphasized in comparison.
But if you want to find the original article you can probably go to
archive.org and use the Wayback Machine to see if the article has been
archived.
This is somewhat frivolous, but related. I don't know much about what
makes a radio mike a radio mike. But, someone commented on this picture
(link below) saying the DJ in the pic would be better off using the
right mike type and angle, and I made a simple comment back about the
angle. But I wondered, if a female DJ did in fact want to eliminate the
proximity effect using this technique, would a mike designed for radio
still be the better mike? Why is a radio mike better for radio (or
usually better, if that's the case) when used in the usual way, than a
MIke singers would pick?
pic (link is to my comment, scroll up for the pic)
http://www.rawstory.com/rs/2012/03/2...ment-470703194
I don't have any graphics, but if the picture is Rush Limbaugh, he
uses an RE-20 which is a microphone with some trickery to greatly reduce
proximity effect. It is popular with broadcasters but it's also a
great PA mike. Tight and even pattern. No "off mike" sound for
people who can't stand still.
In fact, all of the popular broadcast mikes, from the RCA 77 to the
Sennheiser 421, Shure SM-7, EV RE-20, are also great mikes for studio
and PA applications too.
i'm not that interested in commenting back over there, since I have no
experience in this matter, except maybe to point him to this thread if
it illuminates anything.
People are too quick to categorize mikes and say "that is a kick drum mike"
and "that is a studio mike" and "that is a PA mike," when in fact good
clean microphones have a wide variety of applications.
--scott
That URL. I will sort out a new link over the next few days and repost
it somewhere.
As for the proximity effect. It genuinely IS absent at 90 degrees from
the microphone as the velocity component is (near as dammit) zero from
that direction, and only the pressure response is available. Sure you
lose highs from the side - diaphragm geometry sees to that. But that
is not the same thing as bass boost through proximity effect.
d
I goggled around last night and found that it was your article. After
Scott's reading post I thought maybe you took it down because you found
a flaw, which happens to even the best scientists... So late last night
I tested a 0.5 inch cardioid mike I have (AKG blueline) by placing it
one inch away from my metronome speaker which clicks at two different
pitches. I used the metronome because it has a single small speaker, so
direction will be more precise than a multi-speaker speaker. I had to
make two takes, one for each mike position, then for playback I boosted
the gain on the sideways position take to match the other. The bass
boost seemed gone at the sideways position.
I do remember listening to some sound files you put up along with your
article, which were convincing.
Since normal listening is at a distance, and highs get absorbed in the
air, won't the sideways position give you a more realistic tone?
Especially if listening to playback with headphones? I've always
imagined that sound engineers might angle their cardioid mikes closer to
the side as they move from within a foot to even closer to the source,
especially if the source comes from a tight area like a small speaker.
The problem here is that most recordings are made in real rooms, so
the sound arrives from all sorts of angles with varying amounts of
delay. The whole purpose of the directional mic is to try and give a
little added isolation to the direct sound from those delayed
arrivals. So you put up with the proximity effect and kill it with
appropriate eq.
This is where my article can help, because it gives the correct eq for
a set of distances. When I say correct, I mean correct to kill the
proximity boost. You probably need to vary it from that point to
achieve the actual sound you want, but that is another matter.
d