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

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.

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.

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

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

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

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

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

-k

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

-k

"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.