Ludspeakers: How do you judge "neutrality"?
 

"Ian Molton" wrote in message

On Wed, 22 Oct 2003 15:58:12 GMT
(Stewart Pinkerton) wrote:

They use measuring microphones, which are generally flat to better
than 1dB over the audio range, and are also supplied with an
individual calibration curve, so that even that small response error
can be calculated out.

where would I get one, and how much would it cost?


The most common models in general use are shown on these web pages:

http://www.behringer.com/02_products...M8000&lang=eng

http://shop.store.yahoo.com/eawsia/microphones.html

http://www.core-sound.com/dpa4006.html

Ludspeakers: How do you judge "neutrality"?
 

In message , Ian Molton
writes
On Wed, 22 Oct 2003 15:58:12 GMT
(Stewart Pinkerton) wrote:

They use measuring microphones, which are generally flat to better
than 1dB over the audio range, and are also supplied with an
individual calibration curve, so that even that small response error
can be calculated out.

where would I get one, and how much would it cost?


Well a B&K 4133 which is pretty much the reference standard will set you
back the best part of 800 pounds with its battery powered PSU, but it is
ruler flat to about 14kHz, then has a slight rise if it's pointing
straight at the source. I used to have access to one of these in my old
job.

Now I've had to buy my own mic, I use a MUCH cheaper Behringer ECM8000.
Only about 40 pounds, and needs a 15 to 48V phantom feed. The response
is good, but being an electret it is rather noisy. Easily good enough
for LS measurements though.
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

In message , Ian Molton
writes
On Wed, 22 Oct 2003 15:58:12 GMT
(Stewart Pinkerton) wrote:

They use measuring microphones, which are generally flat to better
than 1dB over the audio range, and are also supplied with an
individual calibration curve, so that even that small response error
can be calculated out.

where would I get one, and how much would it cost?


Well a B&K 4133 which is pretty much the reference standard will set you
back the best part of 800 pounds with its battery powered PSU, but it is
ruler flat to about 14kHz, then has a slight rise if it's pointing
straight at the source. I used to have access to one of these in my old
job.

Now I've had to buy my own mic, I use a MUCH cheaper Behringer ECM8000.
Only about 40 pounds, and needs a 15 to 48V phantom feed. The response
is good, but being an electret it is rather noisy. Easily good enough
for LS measurements though.
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?


--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Ludspeakers: How do you judge "neutrality"?
 

On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?


--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Ludspeakers: How do you judge "neutrality"?
 

"Arny Krueger" wrote in message
...
"Dave Plowman" wrote in message

In article ,
Arny Krueger wrote:

SNIP


Much of the current art of audio production is dedicated to getting a
preferred sound that may be nothing like the live performance.



Which is why, IMHO, it is unreasonable to use live music as a reference for
judging how close to accurate a systems reproduction is. With any given CD
(assuming you weren't present at the recording) the listener does not know
how the information on the disc actually sounds. You may assume that, for
example, a violin should sound like a violin, but even ignoring the fact
that individual instruments sound different, you don't know if the
information on a particular recording is, by design or through incompetence,
an exact replica of the original sound.

Ludspeakers: How do you judge "neutrality"?
 

"Arny Krueger" wrote in message
...
"Dave Plowman" wrote in message

In article ,
Arny Krueger wrote:

SNIP


Much of the current art of audio production is dedicated to getting a
preferred sound that may be nothing like the live performance.



Which is why, IMHO, it is unreasonable to use live music as a reference for
judging how close to accurate a systems reproduction is. With any given CD
(assuming you weren't present at the recording) the listener does not know
how the information on the disc actually sounds. You may assume that, for
example, a violin should sound like a violin, but even ignoring the fact
that individual instruments sound different, you don't know if the
information on a particular recording is, by design or through incompetence,
an exact replica of the original sound.

Ludspeakers: How do you judge "neutrality"?
 

In article ,
Ian Molton wrote:
Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

It's funny stuff, phantom. I'd build a completely separate basic 48 volt
supply - deriving it from a lower voltage ain't as easy as it sounds. And
the current needed is tiny, so you could build the whole thing into an
empty wall wart case from the likes of Maplin.

--
*The longest recorded flightof a chicken is thirteen seconds *

Dave Plowman London SW 12
RIP Acorn

Ludspeakers: How do you judge "neutrality"?
 

In article ,
Ian Molton wrote:
Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

It's funny stuff, phantom. I'd build a completely separate basic 48 volt
supply - deriving it from a lower voltage ain't as easy as it sounds. And
the current needed is tiny, so you could build the whole thing into an
empty wall wart case from the likes of Maplin.

--
*The longest recorded flightof a chicken is thirteen seconds *

Dave Plowman London SW 12
RIP Acorn

Ludspeakers: How do you judge "neutrality"?
 

"RPS" wrote in message
...
This is inspired by the recent discussion on possible replacement for
my Spendor BC1's (thanks for all the comments in that thread):

Many of you have commented on a speaker being more or less
neutral/accurate than others.

If you were not present at the original recording session, with good
memory, how can you judge the accuracy of the reproduction?

I mean, I can tell that Spendor, Proac, and Dynaudio are sounding
different, but don't I need to be familiar with the actual original
sound to judge which one is accurate or uncolored?

There are many experienced audiophiles in this forum and I would
appreciate all comments, theoretical as well as how you approach
auditions personally.

Raghu

I get the whole natural thing, I have recently invested in a great sounding
system and was not blown away instantly. Like a lot of the posters have said
it becomes apparent that you are more listening to a replicator than an
processor that alters the tonal qualities of the sound.

This can be a disappointment in some cases as you can hear EVERYTHING. A lot
of CDs that sounded great on my old micro system now sound awful and empty.
I believe some audio can be purposely mixed and mastered to sound better on
smaller systems? But on the other hand an revisiting a lot of my collection
some long forgotten (no so good sounding) albums came alive.

Horses for courses
EggKing

Ludspeakers: How do you judge "neutrality"?
 

"RPS" wrote in message
...
This is inspired by the recent discussion on possible replacement for
my Spendor BC1's (thanks for all the comments in that thread):

Many of you have commented on a speaker being more or less
neutral/accurate than others.

If you were not present at the original recording session, with good
memory, how can you judge the accuracy of the reproduction?

I mean, I can tell that Spendor, Proac, and Dynaudio are sounding
different, but don't I need to be familiar with the actual original
sound to judge which one is accurate or uncolored?

There are many experienced audiophiles in this forum and I would
appreciate all comments, theoretical as well as how you approach
auditions personally.

Raghu

I get the whole natural thing, I have recently invested in a great sounding
system and was not blown away instantly. Like a lot of the posters have said
it becomes apparent that you are more listening to a replicator than an
processor that alters the tonal qualities of the sound.

This can be a disappointment in some cases as you can hear EVERYTHING. A lot
of CDs that sounded great on my old micro system now sound awful and empty.
I believe some audio can be purposely mixed and mastered to sound better on
smaller systems? But on the other hand an revisiting a lot of my collection
some long forgotten (no so good sounding) albums came alive.

Horses for courses
EggKing

Ludspeakers: How do you judge "neutrality"?
 

On Wed, 22 Oct 2003 16:59:39 +0100, Ian Molton wrote:

On Wed, 22 Oct 2003 15:58:12 GMT
(Stewart Pinkerton) wrote:

They use measuring microphones, which are generally flat to better
than 1dB over the audio range, and are also supplied with an
individual calibration curve, so that even that small response error
can be calculated out.

where would I get one, and how much would it cost?

Bruel and Kjaer make arguably the best, and expect to pay anything up
to a grand for the commonly used 4133 model with accessories. A 1/2
inch capsule is probably the best compromise of dynamic range and
frequency response.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Ludspeakers: How do you judge "neutrality"?
 

On Wed, 22 Oct 2003 16:59:39 +0100, Ian Molton wrote:

On Wed, 22 Oct 2003 15:58:12 GMT
(Stewart Pinkerton) wrote:

They use measuring microphones, which are generally flat to better
than 1dB over the audio range, and are also supplied with an
individual calibration curve, so that even that small response error
can be calculated out.

where would I get one, and how much would it cost?

Bruel and Kjaer make arguably the best, and expect to pay anything up
to a grand for the commonly used 4133 model with accessories. A 1/2
inch capsule is probably the best compromise of dynamic range and
frequency response.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Ludspeakers: How do you judge "neutrality"?
 

In article , Ian Molton
wrote:
On Wed, 22 Oct 2003 19:09:28 +0100 Chris Morriss
wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

The currents required are quite small. Hence you might find a suitable box
of batteries will be cheaper and simpler than a mains-based design. Should
make it easier to avoid noise and hum problems.

Your *next* question will then be: How do I deal with the room acoustics?
;-

FWIW I have some B&K mics which I borrow from our research lab, and use
these for in-room measurements of speakers at home. These can be useful as
guides to the sound balance at a chosen listening position. But they
probably tell me more about the room than the speakers when I do this. To
measure the speakers I'd have to take them to the chamber at work. Even
then, the chamber is small, so not much use below 100 Hz or so.

People do not usually use measurement mics for recording purposes as they
tend to be too expensive and fragile. Also, as other have said, recording
engineers often choose a mic with particular 'characteristics' that they
like for various tasks. The 'imperfections' of the mic is then felt to give
a 'good' result. (Matter of judgement.)

If you just want to get an idea of the speaker performance in a room, a
reasonably calibrated mic and 1/3rd octave signals should be fine. However
if you want to understand the actual speakers, you'd need to use a chamber,
or do pulsed measurements, or an alternative that allows you to unscramble
the effects of the surroundings.

Also, if you want to understand why speakers that give similar in-room
responses still can sound different, you'd have to explore things like
speaker directionality patterns and their interactions with the room
acoustic. :-) For various reasons, a response that does not seem 'flat'
in a simple 1/3rd octave measurement may turn out to be preferred in
practice. Hence this info can be useful for reference purposes, but should
not be taken as meaning you have to get a 'flat response' from such
measurements for the system to be at its best.

The harder you look, the more details appear. ;-

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Ludspeakers: How do you judge "neutrality"?
 

In article , Ian Molton
wrote:
On Wed, 22 Oct 2003 19:09:28 +0100 Chris Morriss
wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

The currents required are quite small. Hence you might find a suitable box
of batteries will be cheaper and simpler than a mains-based design. Should
make it easier to avoid noise and hum problems.

Your *next* question will then be: How do I deal with the room acoustics?
;-

FWIW I have some B&K mics which I borrow from our research lab, and use
these for in-room measurements of speakers at home. These can be useful as
guides to the sound balance at a chosen listening position. But they
probably tell me more about the room than the speakers when I do this. To
measure the speakers I'd have to take them to the chamber at work. Even
then, the chamber is small, so not much use below 100 Hz or so.

People do not usually use measurement mics for recording purposes as they
tend to be too expensive and fragile. Also, as other have said, recording
engineers often choose a mic with particular 'characteristics' that they
like for various tasks. The 'imperfections' of the mic is then felt to give
a 'good' result. (Matter of judgement.)

If you just want to get an idea of the speaker performance in a room, a
reasonably calibrated mic and 1/3rd octave signals should be fine. However
if you want to understand the actual speakers, you'd need to use a chamber,
or do pulsed measurements, or an alternative that allows you to unscramble
the effects of the surroundings.

Also, if you want to understand why speakers that give similar in-room
responses still can sound different, you'd have to explore things like
speaker directionality patterns and their interactions with the room
acoustic. :-) For various reasons, a response that does not seem 'flat'
in a simple 1/3rd octave measurement may turn out to be preferred in
practice. Hence this info can be useful for reference purposes, but should
not be taken as meaning you have to get a 'flat response' from such
measurements for the system to be at its best.

The harder you look, the more details appear. ;-

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Ludspeakers: How do you judge "neutrality"?
 

"Ian Molton" wrote in message


On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:

Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good,

I taped one to the side of a DPA 4006, aligned the fronts and measured the
frequency response of a speaker. The two response curves sat on top of each
other from about 50 to 15 KHz. The ECM 8000 has -3 dB points around 40 Hz
and 20 KHz. Above 10 KHz neither the 4006 nor the 8000 are perfectly flat,
and they're unflat a bit differently.

I also did some distortion measurement comparisons and they were too much
the same to talk about.

but being an electret it is rather noisy.

People say that but other people (like me) use them for recording and get
good results.

One thing for sure - the 8000 puts out a good strong output signal. Stronger
than most. Pop one onto a cable that had a live SM57 on it and you'll have
feedback, for sure.

In general, the quietest mics in the world aren't electrets but there are
lots of conventional condensers that are as noisy or noisier than the best
electrets.

IME the 8000's reputation for being noisy is at least partially based on the
fact that it does have a lot of output and it is a lot more omnidirectional,
especially above 10 KHz, than just about any other mic that most people have
real world experience with.

Easily good enough for LS measurements though.

One well-known guy who uses the ECM-8000 for development is Ken Kantor of
NHT fame.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

Bag the mic input on the PC and get a cheap Behringer mixer with a
phantom-powered mic input or a cheap mic preamp like the Rolls MP13.

Ludspeakers: How do you judge "neutrality"?
 

"Ian Molton" wrote in message


On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:

Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good,

I taped one to the side of a DPA 4006, aligned the fronts and measured the
frequency response of a speaker. The two response curves sat on top of each
other from about 50 to 15 KHz. The ECM 8000 has -3 dB points around 40 Hz
and 20 KHz. Above 10 KHz neither the 4006 nor the 8000 are perfectly flat,
and they're unflat a bit differently.

I also did some distortion measurement comparisons and they were too much
the same to talk about.

but being an electret it is rather noisy.

People say that but other people (like me) use them for recording and get
good results.

One thing for sure - the 8000 puts out a good strong output signal. Stronger
than most. Pop one onto a cable that had a live SM57 on it and you'll have
feedback, for sure.

In general, the quietest mics in the world aren't electrets but there are
lots of conventional condensers that are as noisy or noisier than the best
electrets.

IME the 8000's reputation for being noisy is at least partially based on the
fact that it does have a lot of output and it is a lot more omnidirectional,
especially above 10 KHz, than just about any other mic that most people have
real world experience with.

Easily good enough for LS measurements though.

One well-known guy who uses the ECM-8000 for development is Ken Kantor of
NHT fame.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?

Bag the mic input on the PC and get a cheap Behringer mixer with a
phantom-powered mic input or a cheap mic preamp like the Rolls MP13.

Ludspeakers: How do you judge "neutrality"?
 

"struan" wrote in message

"Arny Krueger" wrote in message
...
"Dave Plowman" wrote in message

In article ,
Arny Krueger wrote:

SNIP


Much of the current art of audio production is dedicated to getting a
preferred sound that may be nothing like the live performance.

Which is why, IMHO, it is unreasonable to use live music as a
reference for judging how close to accurate a systems reproduction
is.

In general that seems to be a pretty well-supported point.

Those of us who record our own, can differ.

With any given CD (assuming you weren't present at the recording)
the listener does not know how the information on the disc actually
sounds.

Obviously untrue if the listener is a LP bigot! ;-) These guys just know
what the information on the disc actually sounds like. ;-)

You may assume that, for example, a violin should sound like
a violin, but even ignoring the fact that individual instruments
sound different, you don't know if the information on a particular
recording is, by design or through incompetence, an exact replica of
the original sound.

I totally agree. Furthermore, if you go out of your way to make a nice
accurate recording of a violin, a lot of music lovers and engineers will
tell you it sounds dead and lifeless, or something like that.

Ludspeakers: How do you judge "neutrality"?
 

"struan" wrote in message

"Arny Krueger" wrote in message
...
"Dave Plowman" wrote in message

In article ,
Arny Krueger wrote:

SNIP


Much of the current art of audio production is dedicated to getting a
preferred sound that may be nothing like the live performance.

Which is why, IMHO, it is unreasonable to use live music as a
reference for judging how close to accurate a systems reproduction
is.

In general that seems to be a pretty well-supported point.

Those of us who record our own, can differ.

With any given CD (assuming you weren't present at the recording)
the listener does not know how the information on the disc actually
sounds.

Obviously untrue if the listener is a LP bigot! ;-) These guys just know
what the information on the disc actually sounds like. ;-)

You may assume that, for example, a violin should sound like
a violin, but even ignoring the fact that individual instruments
sound different, you don't know if the information on a particular
recording is, by design or through incompetence, an exact replica of
the original sound.

I totally agree. Furthermore, if you go out of your way to make a nice
accurate recording of a violin, a lot of music lovers and engineers will
tell you it sounds dead and lifeless, or something like that.

Ludspeakers: How do you judge "neutrality"?
 

In message , Ian Molton
writes
On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?



Have a look in the SSM2019 app note on the Analog Devices web site. I
use the same pre-amp (but using the older SSM2017 part) with my Mic. I
battery power the pre-amp from two Yuasa 12V batteries.

The output of the pre-amp goes straight into my soundcard (For use with
True-RTA) or into my HP FFT analyser.
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

In message , Ian Molton
writes
On Wed, 22 Oct 2003 19:09:28 +0100
Chris Morriss wrote:


Now I've had to buy my own mic, I use a MUCH cheaper Behringer
ECM8000.

The price is right...

The response is good, but being an electret it is rather noisy.
Easily good enough for LS measurements though.

Ok, so given that, the next question is:

How do I fudge a 'phantom powered' XLR mic into the mic in on my PC ?



Have a look in the SSM2019 app note on the Analog Devices web site. I
use the same pre-amp (but using the older SSM2017 part) with my Mic. I
battery power the pre-amp from two Yuasa 12V batteries.

The output of the pre-amp goes straight into my soundcard (For use with
True-RTA) or into my HP FFT analyser.
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

On Thu, 23 Oct 2003 09:11:41 +0100
Jim Lesurf wrote:


The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Your *next* question will then be: How do I deal with the room
acoustics?
;-

I suppose really I want to profile the room. pulsed measurements of my
speakers would be fun though.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Ludspeakers: How do you judge "neutrality"?
 

On Thu, 23 Oct 2003 09:11:41 +0100
Jim Lesurf wrote:


The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Your *next* question will then be: How do I deal with the room
acoustics?
;-

I suppose really I want to profile the room. pulsed measurements of my
speakers would be fun though.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

Ludspeakers: How do you judge "neutrality"?
 

In article ,
Ian Molton wrote:
The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Unless you intend long periods of use 4 PP3s should give about 50 hours at
least, although it's very much dependant on the mic. Some older AKG types
like the early 451s are happy on 9 volts - others may need 40+.

--
*Remember not to forget that which you do not need to know.*

Dave Plowman London SW 12
RIP Acorn

Ludspeakers: How do you judge "neutrality"?
 

In article ,
Ian Molton wrote:
The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Unless you intend long periods of use 4 PP3s should give about 50 hours at
least, although it's very much dependant on the mic. Some older AKG types
like the early 451s are happy on 9 volts - others may need 40+.

--
*Remember not to forget that which you do not need to know.*

Dave Plowman London SW 12
RIP Acorn

Ludspeakers: How do you judge "neutrality"?
 

In message , Dave Plowman
writes
In article ,
Ian Molton wrote:
The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Unless you intend long periods of use 4 PP3s should give about 50 hours at
least, although it's very much dependant on the mic. Some older AKG types
like the early 451s are happy on 9 volts - others may need 40+.


On my SSM2017 pre-amp I use two gel-type lead-acid batteries to give me
+/- 12V for the chip, and I then use an isolated dc-dc convertor running
off the total 24V to provide a 0V referenced +30V for the phantom feed.

On the CM8000 the phantom feed is only to power the pre-amp as the mic
cartridge is an electret and doesn't need an external polarising supply.

(On the professional capacitor mics like the B&K 4133 the battery supply
is stepped up to a couple of hundred volts to polarise the capacitor
cartridge).
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

In message , Dave Plowman
writes
In article ,
Ian Molton wrote:
The currents required are quite small. Hence you might find a suitable
box of batteries will be cheaper and simpler than a mains-based
design. Should make it easier to avoid noise and hum problems.

Indeed. When it says '15-48V' does it really mean anything in that
range? if so, the pair of 12V cells someone suggested is probably the
way to go.

Unless you intend long periods of use 4 PP3s should give about 50 hours at
least, although it's very much dependant on the mic. Some older AKG types
like the early 451s are happy on 9 volts - others may need 40+.


On my SSM2017 pre-amp I use two gel-type lead-acid batteries to give me
+/- 12V for the chip, and I then use an isolated dc-dc convertor running
off the total 24V to provide a 0V referenced +30V for the phantom feed.

On the CM8000 the phantom feed is only to power the pre-amp as the mic
cartridge is an electret and doesn't need an external polarising supply.

(On the professional capacitor mics like the B&K 4133 the battery supply
is stepped up to a couple of hundred volts to polarise the capacitor
cartridge).
--
Chris Morriss

Ludspeakers: How do you judge "neutrality"?
 

The ECM8000 is a superb mic, especially for the $$.

-k

Ludspeakers: How do you judge "neutrality"?
 

The ECM8000 is a superb mic, especially for the $$.

-k

Ludspeakers: How do you judge "neutrality"?
 

"Ken Kantor" wrote in message
om

The ECM8000 is a superb mic, especially for the $$.

Agreed. For the money it's an absolute steal. The next mic up the food chain
that even vaguely compares is about 5 times more bucks.

Used appropriately, it's very good for SR & recording.

The ECM 8000 has a reputation for being noisy and having limited dynamic
range.

IME its' real *problems* are that it has lots of sensitivity and is far more
truly ominidirectional that any mic most people have ever seen.

The high output means that any noise it picks up or makes is more apparent.
The high output means that it is likely to clip out cheap mic preamps like
those in Mackie consoles (properly applying mic attenuators seems to be a
lost art in many quarters).

The fact that it is so omnidirectional above 5 KHz makes it extraordinarily
sensitive to hissy noises related to air movement and the like, compared
even to so-called omnidirectional mics of a more conventional design.

Ludspeakers: How do you judge "neutrality"?
 

"Ken Kantor" wrote in message
om

The ECM8000 is a superb mic, especially for the $$.

Agreed. For the money it's an absolute steal. The next mic up the food chain
that even vaguely compares is about 5 times more bucks.

Used appropriately, it's very good for SR & recording.

The ECM 8000 has a reputation for being noisy and having limited dynamic
range.

IME its' real *problems* are that it has lots of sensitivity and is far more
truly ominidirectional that any mic most people have ever seen.

The high output means that any noise it picks up or makes is more apparent.
The high output means that it is likely to clip out cheap mic preamps like
those in Mackie consoles (properly applying mic attenuators seems to be a
lost art in many quarters).

The fact that it is so omnidirectional above 5 KHz makes it extraordinarily
sensitive to hissy noises related to air movement and the like, compared
even to so-called omnidirectional mics of a more conventional design.