[mcp6453[_2_]]

It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

[[email protected]]

On Monday, January 9, 2017 at 10:42:08 AM UTC-5, mcp6453 wrote:
It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

not sure if this is what you mean

Haas effect

https://en.wikipedia.org/wiki/Precedence_effect

m

[Scott Dorsey]

In article ,
mcp6453 wrote:
It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

I think you're talking about the 1:3 rule, which is a sort of mixture of
physics and psychoacoustics and possibly unwarranted assumptions.

IF you have two microphones and IF they are cardioids, and IF the distance
between the microphones is more than three times the distance between the
microphones and the sources, then you're apt to hear audible comb filtering
when the mikes are mixed at identical levels.

Now, there are a whole lot of assumptions involved in that. It's assuming
the microphone is getting a certain amount of off-axis leakage, and it's
assuming that you're not noticing comb filtering below a certain point, and
it's assuming everything is more or less at the same level in the mix.

But it's still a reasonable rule to follow that is mostly accurate. For
recording in the digital world we can use time delay to line mikes up so
that the comb filtering either disappears or becomes so great that it's
no longer an issue. In the PA world you don't really get much ability to
do that, nor can you do it in the analogue mixing world.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers[_2_]]

On 1/9/2017 7:41 AM, mcp6453 wrote:
It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

Are you really talking about masking (meaning you hear one and not the
other), or are you asking about the cancellation or partial reduction of
certain frequencies that results when mixing the signal from two mics
picking up the same source? This is usually called "phase cancellation."

The amplitude difference between the mics affects how deep the notches
in the combined frequency response are. A 3:1 difference in amplitude is
10 dB, which is usually enough so that the irregularities in the
frequency response isn't too bothersome. With only 10 dB difference,
you'll hear both vocals in both mics and you won't have objectionable
phase cancellation, but you might want to shoot for better isolation
than that to make mixing easier. If you have to use a lot of EQ on one
vocal, remember that you're adding that same EQ, at least a little, to
the other vocal. This can be significant if the two mics are panned
fairly far apart in a mix.

There's no magic number, just whatever works. If you think you're going
to have a problem, consider having both vocalists work together on a
single mic. You may have heard of the "three-to-one" rule. This says
that you won't have too much of a problem with phase cancellation if the
distance between two mics is three times the distance between the
distance to the source of the mic that's the most distant of the two.
For example, if your singers were both singing 3 inches from their mics,
you'd be safe if the mics were more than 9 inches apart, which isn't
much of a problem. But if they're singing 10 inches back from the mics,
the mics should be about a yard apart. And with a setup like that, there
will probably be other things going into the mics that you don't want.




--
"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

Drop by http://mikeriversaudio.wordpress.com now and then

[Mike Rivers[_2_]]

On 1/9/2017 9:36 AM, Scott Dorsey wrote:
IF you have two microphones and IF they are cardioids, and IF the distance
between the microphones is more than three times the distance between the
microphones and the sources, then you're apt to hear audible comb filtering
when the mikes are mixed at identical levels.

Now that you mention it, I think that the "official" 3:1 rule is for
omni mics, and with cardioids you can cheat it a bit. But better to just
listen to be sure you don't have a problem, and fix it if you do.

--
"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

Drop by http://mikeriversaudio.wordpress.com now and then

[JackA]

On Monday, January 9, 2017 at 10:42:08 AM UTC-5, mcp6453 wrote:
It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

I like that word, "masking". How I compare Monophonic recordings to Stereo. See, no one ever tells you why you like some things, you have to figure it out yourself. Anyway, Masking of Sounds...
https://en.wikipedia.org/wiki/Sound_masking

Jack

[Rasta Robert]

On 2017-01-10, JackA wrote:
On Monday, January 9, 2017 at 10:42:08 AM UTC-5, mcp6453 wrote:
It's been a long time since I heard the explanation, but there
is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix.
The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

I like that word, "masking". How I compare Monophonic recordings to Stereo.
See, no one ever tells you why you like some things, you have to figure
it out yourself. Anyway, Masking of Sounds...
https://en.wikipedia.org/wiki/Sound_masking

Jack

The article linked to above describes a specific application of what
is more generally described in the wikipedia article about
auditory masking: https://en.wikipedia.org/wiki/Auditory_masking

[Ty Ford]

On Monday, January 9, 2017 at 10:42:08 AM UTC-5, mcp6453 wrote:
It's been a long time since I heard the explanation, but there is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix. The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

I think you may be referring to the 3 to 1 rule that explains how far away one mic has to be from a source than another to achieve basic isolation.

The Haas effect has to do with how many milliseconds of delay can be used before the delayed signal sounds like a discrete echo. Typically that's around 20 mSec.

Regards,

Ty Ford

[Phil Allison[_4_]]

Ty Ford wrote:



The Haas effect has to do with how many milliseconds of delay can be
used before the delayed signal sounds like a discrete echo.
Typically that's around 20 mSec.



** The Hass effect has to do with the perceived direction and level of a sound that is followed by an echo arriving a short time later. An echo arriving from a different direction, even if significantly louder, does not alter the apparent direction of the first arriving sound.

Several times I have been asked to track down mysterious leakage of signal from the PLF of a mixing desk to the FOH outputs. The was none found.

On each occasion, the operator had phones plugged into the desk left sitting in front of him while he PFLd various mic channels. A he did so, the voice or instrument concerned jumped up in level - due to the Hass effect.

Of course, no other person could hear this level change unless they also sat at the desk.

https://en.wikipedia.org/wiki/Precedence_effect#History


..... Phil

[JackA]

On Tuesday, January 10, 2017 at 7:36:56 PM UTC-5, Rasta Robert wrote:
On 2017-01-10, JackA wrote:
On Monday, January 9, 2017 at 10:42:08 AM UTC-5, mcp6453 wrote:
It's been a long time since I heard the explanation, but there
is a ratio below which a foreground vocal will mask a
second microphone's pickup of that same vocal in the mix.
The ratio of the amplitude is 1:3, as I recall. Can anyone
tell me what that effect (or law of physics or phenomenon) is called?

I like that word, "masking". How I compare Monophonic recordings to Stereo.
See, no one ever tells you why you like some things, you have to figure
it out yourself. Anyway, Masking of Sounds...
https://en.wikipedia.org/wiki/Sound_masking

Jack

The article linked to above describes a specific application of what
is more generally described in the wikipedia article about
auditory masking: https://en.wikipedia.org/wiki/Auditory_masking

Nice find, thank you!

Jack

[PStamler]

The "3-to-1" rule only applies when the sounds are about the same level from each of your sources. A more effective rule is to say that the leakage should be at least 10dB below the direct sound.

Peace,
Paul