Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna emphasize
bass frequencies when taking it near the sound source, right? Also isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that the
bass increases when getting closer to the sound source. I know it's got to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize it
and understand it's character as a physical effect?

2. What values do the compressor ratio settings actually represent? I mean,
a ratio of 2:1 can't obviously mean "halving" the signal above the
threshold; if it's 2dB over and becomes one, then it can't be so that a 2:1
ratio would also result in 10dB over becoming 5dB, right?

Thanks for your answers!

In article , "Tommi"
writes:

2. What values do the compressor ratio settings actually represent? I mean,
a ratio of 2:1 can't obviously mean "halving" the signal above the
threshold; if it's 2dB over and becomes one, then it can't be so that a 2:1
ratio would also result in 10dB over becoming 5dB, right?


If I understand your question then yes it is what you describe above. If the
signal going into the copmpressor exceeds the threshold by 4 dB and the ratio
is 2:1 then the output of the compressor will be 2dB above the threshold rather
than 4 dB above.

Garth~


"I think the fact that music can come up a wire is a miracle."
Ed Cherney

In article , "Tommi"
writes:

2. What values do the compressor ratio settings actually represent? I mean,
a ratio of 2:1 can't obviously mean "halving" the signal above the
threshold; if it's 2dB over and becomes one, then it can't be so that a 2:1
ratio would also result in 10dB over becoming 5dB, right?


If I understand your question then yes it is what you describe above. If the
signal going into the copmpressor exceeds the threshold by 4 dB and the ratio
is 2:1 then the output of the compressor will be 2dB above the threshold rather
than 4 dB above.

Garth~


"I think the fact that music can come up a wire is a miracle."
Ed Cherney

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna emphasize
bass frequencies when taking it near the sound source, right? Also isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that the
bass increases when getting closer to the sound source. I know it's got to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.
The math that quantifies this is derived in section 3.5 (in
chapter 3) of Phillip Cotterell's definitive thesis on the
theory of directional microphones at:

http://www.personal.rdg.ac.uk/~shr97psc/Thesis.html


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna emphasize
bass frequencies when taking it near the sound source, right? Also isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that the
bass increases when getting closer to the sound source. I know it's got to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.
The math that quantifies this is derived in section 3.5 (in
chapter 3) of Phillip Cotterell's definitive thesis on the
theory of directional microphones at:

http://www.personal.rdg.ac.uk/~shr97psc/Thesis.html


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Bob Cain wrote:

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna emphasize
bass frequencies when taking it near the sound source, right? Also isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that the
bass increases when getting closer to the sound source. I know it's got to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.

Bob,

More simply put, pressure gradient mic patterns are a combination of pressure
(omni) and velocity (bi-directional) patterns, mixed together in varying
degrees. As you move within 3 feet, the velocity component starts to have
greater effect and that builds up as you get closer to the mic. All velocity
mics (and any pressure gradient design) have this rising bass response
characteristic as you get closer, as the velocity component swamps the pressure
component.

(This next part is for Tommi, since Bob already knows this stuff.)

That's why on a multi pattern mic, you'll always find omni (pressure only) on
one end of the pattern settings, and velocity (also called bi-directional, or
fig. 8) at the other extreme of the pattern settings. All the rest of the
in-between patterns are simply varying mixtures of these two patterns.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

Bob Cain wrote:

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna emphasize
bass frequencies when taking it near the sound source, right? Also isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that the
bass increases when getting closer to the sound source. I know it's got to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.

Bob,

More simply put, pressure gradient mic patterns are a combination of pressure
(omni) and velocity (bi-directional) patterns, mixed together in varying
degrees. As you move within 3 feet, the velocity component starts to have
greater effect and that builds up as you get closer to the mic. All velocity
mics (and any pressure gradient design) have this rising bass response
characteristic as you get closer, as the velocity component swamps the pressure
component.

(This next part is for Tommi, since Bob already knows this stuff.)

That's why on a multi pattern mic, you'll always find omni (pressure only) on
one end of the pattern settings, and velocity (also called bi-directional, or
fig. 8) at the other extreme of the pattern settings. All the rest of the
in-between patterns are simply varying mixtures of these two patterns.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

Are there any microphone placements that can minimize the bass response on
very directional mics?
Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?
What highly directional microphones handle off axis response the best?

Just wondering, thanks.

Martin


"Harvey Gerst" wrote in message
news
Bob Cain wrote:

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna
emphasize
bass frequencies when taking it near the sound source, right? Also
isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that
the
bass increases when getting closer to the sound source. I know it's got
to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize
it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.

Bob,

More simply put, pressure gradient mic patterns are a combination of
pressure
(omni) and velocity (bi-directional) patterns, mixed together in varying
degrees. As you move within 3 feet, the velocity component starts to have
greater effect and that builds up as you get closer to the mic. All
velocity
mics (and any pressure gradient design) have this rising bass response
characteristic as you get closer, as the velocity component swamps the
pressure
component.

(This next part is for Tommi, since Bob already knows this stuff.)

That's why on a multi pattern mic, you'll always find omni (pressure only)
on
one end of the pattern settings, and velocity (also called bi-directional,
or
fig. 8) at the other extreme of the pattern settings. All the rest of the
in-between patterns are simply varying mixtures of these two patterns.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

Are there any microphone placements that can minimize the bass response on
very directional mics?
Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?
What highly directional microphones handle off axis response the best?

Just wondering, thanks.

Martin


"Harvey Gerst" wrote in message
news
Bob Cain wrote:

Tommi wrote:

Hello everyone, two things I've been wondering:

1. The more directional your mic is, the more likely it's gonna
emphasize
bass frequencies when taking it near the sound source, right? Also
isn't it
so that angling the mic 45 degrees or so helps to minimize this effect?
Anyway, I don't fully understand(or at least I'm not having an inner
knowledge of it so I could visualize it), why is it actually so that
the
bass increases when getting closer to the sound source. I know it's got
to
do with the wavelenghts, but can't figure out how and why the so-called
proximity effect happens.
Could anyone explain clearly the proximity effect, so I could visualize
it
and understand it's character as a physical effect?

I can't. It takes some reasonably serious math to show it
and I'm at a loss for a way to put that math in more
intuitive terms. In essense, but without much explanatory
power, it is because directive mics are based on measuring
the difference in pressure between two points in space and
in some way integrating that difference with respect to
time. That combined with the fact that the wave front
becomes more and more spherical and less planar as you get
closer to the source yields a boost whose magnitude is a
function of the inverse of both distance and of frequency.

Bob,

More simply put, pressure gradient mic patterns are a combination of
pressure
(omni) and velocity (bi-directional) patterns, mixed together in varying
degrees. As you move within 3 feet, the velocity component starts to have
greater effect and that builds up as you get closer to the mic. All
velocity
mics (and any pressure gradient design) have this rising bass response
characteristic as you get closer, as the velocity component swamps the
pressure
component.

(This next part is for Tommi, since Bob already knows this stuff.)

That's why on a multi pattern mic, you'll always find omni (pressure only)
on
one end of the pattern settings, and velocity (also called bi-directional,
or
fig. 8) at the other extreme of the pattern settings. All the rest of the
in-between patterns are simply varying mixtures of these two patterns.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

"Martin" wrote:

Are there any microphone placements that can minimize the bass response on
very directional mics?

3 feet away or greater.

Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?

Bi-directional velocity mics (usually) have the smoothest off-axis response.

What highly directional microphones handle off axis response the best?

See above.

Just wondering, thanks.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

"Martin" wrote:

Are there any microphone placements that can minimize the bass response on
very directional mics?

3 feet away or greater.

Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?

Bi-directional velocity mics (usually) have the smoothest off-axis response.

What highly directional microphones handle off axis response the best?

See above.

Just wondering, thanks.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

"Garthrr" wrote in message
...
If I understand your question then yes it is what you describe above. If
the
signal going into the copmpressor exceeds the threshold by 4 dB and the
ratio
is 2:1 then the output of the compressor will be 2dB above the threshold
rather
than 4 dB above.

So, it really is like that? If I can make it any more clear, the thing I
meant was:
a ratio of 2:1 means halving the signal.
When the signal passes the threshold, it will always be compressed to half
of its original...what? sound pressure level? voltage?
I mean, if they were decibels, the compressor would have to calculate the
signal logarithmically, since (with a 2:1 ratio) 2 dB becoming 1 dB, 4 dB
becoming 2 dB, and 10 dB becoming 5 dB are all different SPL ratios when
compared to each other..this is the thing I'm wondering, what values do the
numbers on the ratio setting actually represent? If anyone has any clue,
enlighten me!

"Garthrr" wrote in message
...
If I understand your question then yes it is what you describe above. If
the
signal going into the copmpressor exceeds the threshold by 4 dB and the
ratio
is 2:1 then the output of the compressor will be 2dB above the threshold
rather
than 4 dB above.

So, it really is like that? If I can make it any more clear, the thing I
meant was:
a ratio of 2:1 means halving the signal.
When the signal passes the threshold, it will always be compressed to half
of its original...what? sound pressure level? voltage?
I mean, if they were decibels, the compressor would have to calculate the
signal logarithmically, since (with a 2:1 ratio) 2 dB becoming 1 dB, 4 dB
becoming 2 dB, and 10 dB becoming 5 dB are all different SPL ratios when
compared to each other..this is the thing I'm wondering, what values do the
numbers on the ratio setting actually represent? If anyone has any clue,
enlighten me!

Martin wrote:
Are there any microphone placements that can minimize the bass response on
very directional mics?

No.

Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?

If you move off-axis, you will get less top end and just as much bass.
Directional microphones are only directional at high frequencies.

What highly directional microphones handle off axis response the best?

The Schoeps are pretty good. The Josephson Series 6 is pretty good, too.
--scott

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

Martin wrote:
Are there any microphone placements that can minimize the bass response on
very directional mics?

No.

Does angling the mic 45 degrees help? If so, does that not introduce other
problems like off axis response?

If you move off-axis, you will get less top end and just as much bass.
Directional microphones are only directional at high frequencies.

What highly directional microphones handle off axis response the best?

The Schoeps are pretty good. The Josephson Series 6 is pretty good, too.
--scott

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