Behringer ECM8000 help req.
Witek
Can anyone please tell me if the Behringer ECM8000 requires 48V of
phantom power to preform according to specs. ( as stated on the freq.
response graph)
What I'm basically trying to ask is, if I take and build my own
phantom power supply and it only supply it with lets say 17V, will the
mike still preform according to what the specs state? Im going to do
room equilisation measurements with the thing, so the freq response
properties are rather important to me.
I have no phantom power supply yet, so I can test anything myself.
Can anyone with any experience with the ECM8000 shed some light on the
matter?
Thanks
Witek.
Arny Krueger
news:988ae42c.04031...@posting.google.com
> Can anyone please tell me if the Behringer ECM8000 requires 48V of
> phantom power to perform according to specs. ( as stated on the freq.
> response graph)
48 volts is not an absolute requirement for the ECM 8000 . It works well
with considerably less phantom voltage. Inside the mic there is a regulated
power supply running someplace around 12 volts.
> What I'm basically trying to ask is, if I take and build my own
> phantom power supply and it only supply it with lets say 17V, will the
> mike still perform according to what the specs state?
Actually, the ECM 8000 you buy today will probably not precisely meet
Behringer's published specs because they've changed the mic considerably
without changing the model number or spec sheet.
There are two significantly different ECM 8000 designs, one with a FET and a
transformer and true balanced output, and one with an IC buffer and
transfomerless output. I don't recommend disassembling yours to identify it,
as the mic element leads are very fine and are exceedingly easy to break.
The resistance to ground from pins 2 & 3 of a mic I know for sure to be
transformerless was about 200 K, and from pin 2 to 3 I measured 330 K with a
DVM. I presume that the transformer version would have a far smaller
resistance between pins 2 & 3.
I've only seen detailed photos of the transformer version.
>I'm going to do
> room equalization measurements with the thing, so the freq response
> properties are rather important to me.
Another thing to remember is that the ECM 8000 rolls off the bass end, with
its - 3dB point someplace around 40 Hz.
> I have no phantom power supply yet, so I can test anything myself.
> Can anyone with any experience with the ECM8000 shed some light on the
> matter?
It's a great mic for the price, and not a bad mic overall. Ken Kantor
(senior designer for AR & founder of NHT and Mergence) turned me on to them.
I've compared them side-by-side to B&K mics costing about 40 times as much.
From 40 to 23 KHz, it's a horse race in terms of frequency response. BTW,
Ken recommended using them with Rolls MP-13 mic preamps that only put out
about 22 volts of phantom power.
Simon Byrnand
"Arny Krueger" <ar...@hotpop.com> wrote in message news:<6b6dnWUDAv8...@comcast.com>...
> "Witek" <wi...@dsp.sun.ac.za> wrote in message
> news:988ae42c.04031...@posting.google.com
>
> > Can anyone please tell me if the Behringer ECM8000 requires 48V of
> > phantom power to perform according to specs. ( as stated on the freq.
> > response graph)
>
> 48 volts is not an absolute requirement for the ECM 8000 . It works well
> with considerably less phantom voltage. Inside the mic there is a regulated
> power supply running someplace around 12 volts.
I just recently got an ECM8000 to go with the DEQ2496 equalizer, and
the measured phantom voltage on the MIC input of that is only 14.9v so
one would assume that anything from 15v to 48v would be ok if they
have a built in 12v regulator...(I havn't actually got around to doing
a sensitivity vs voltage measurement yet, but will some time)
> > What I'm basically trying to ask is, if I take and build my own
> > phantom power supply and it only supply it with lets say 17V, will the
> > mike still perform according to what the specs state?
>
> Actually, the ECM 8000 you buy today will probably not precisely meet
> Behringer's published specs because they've changed the mic considerably
> without changing the model number or spec sheet.
Hmm, interesting.... do you have any info on how they are different ?
Sensitivity ? Rolloff frequencies etc ? Have you done any direct
comparision between them ?
> There are two significantly different ECM 8000 designs, one with a FET and a
> transformer and true balanced output, and one with an IC buffer and
> transfomerless output. I don't recommend disassembling yours to identify it,
> as the mic element leads are very fine and are exceedingly easy to break.
> The resistance to ground from pins 2 & 3 of a mic I know for sure to be
> transformerless was about 200 K, and from pin 2 to 3 I measured 330 K with a
> DVM. I presume that the transformer version would have a far smaller
> resistance between pins 2 & 3.
Just measured mine and I get 196K from ground to pin 2 or 3, and 355K
from pin 2 to pin 3, so I guess I have the one without the
transformer. Bit sneaky that the box still shows a diagram of a
transformer coupled output ;-)
> I've only seen detailed photos of the transformer version.
>
> >I'm going to do
> > room equalization measurements with the thing, so the freq response
> > properties are rather important to me.
>
> Another thing to remember is that the ECM 8000 rolls off the bass end, with
> its - 3dB point someplace around 40 Hz.
Was that for the original transformer version or the new IC version ?
If that was for the transformer version its possible that the
transformer itself may have been rolling off the bottom end as well,
and the IC version may go a bit lower...(one can hope anyway ;)
> > I have no phantom power supply yet, so I can test anything myself.
> > Can anyone with any experience with the ECM8000 shed some light on the
> > matter?
>
> It's a great mic for the price, and not a bad mic overall. Ken Kantor
> (senior designer for AR & founder of NHT and Mergence) turned me on to them.
> I've compared them side-by-side to B&K mics costing about 40 times as much.
> From 40 to 23 KHz, it's a horse race in terms of frequency response. BTW,
> Ken recommended using them with Rolls MP-13 mic preamps that only put out
> about 22 volts of phantom power.
Good to know... definately seems like a good little mic for the price,
I also made up a transformer based balanced to unbalanced isolation
and phantom power box using a couple of 9v batteries so I could use it
with my computer, and it seems to work fine. Pity about the bottom end
rolloff below 40Hz though. (Although the previous microphone I had
rolled off below 150Hz so its a definite improvement :)
Was Ken refering to the tranformer version or IC version ?
Regards,
Simon
Arny Krueger
news:e524ab46.04031...@posting.google.com
> Hi Arny,
> "Arny Krueger" <ar...@hotpop.com> wrote in message
> news:<6b6dnWUDAv8...@comcast.com>...
>> "Witek" <wi...@dsp.sun.ac.za> wrote in message
>> news:988ae42c.04031...@posting.google.com
>>> Can anyone please tell me if the Behringer ECM8000 requires 48V of
>>> phantom power to perform according to specs. ( as stated on the
>>> freq. response graph)
>> 48 volts is not an absolute requirement for the ECM 8000 . It works
>> well with considerably less phantom voltage. Inside the mic there is
>> a regulated power supply running someplace around 12 volts.
> I just recently got an ECM8000 to go with the DEQ2496 equalizer, and
> the measured phantom voltage on the MIC input of that is only 14.9v so
> one would assume that anything from 15v to 48v would be ok if they
> have a built in 12v regulator...(I haven't actually got around to doing
> a sensitivity vs. voltage measurement yet, but will some time)
I think that was true of the two previous generations of Ultracurve as well.
There is a standard involving low Phantom voltages in the 12-15 volt range.
A Friend has a Benchmark Media mic preamp with 15 volt phantom power as
well.
>>> What I'm basically trying to ask is, if I take and build my own
>>> phantom power supply and it only supply it with lets say 17V, will
>>> the mike still perform according to what the specs state?
>> Actually, the ECM 8000 you buy today will probably not precisely meet
>> Behringer's published specs because they've changed the mic
>> considerably without changing the model number or spec sheet.
> Hmm, interesting.... do you have any info on how they are different ?
No, just the web page I cited.
http://www.imagendv.com/altavoces/micro_med.htm
> Sensitivity ? Rolloff frequencies etc ? Have you done any direct
> comparision between them ?
I've never actually had one of the old-style ECM 8000s in my hands.
>> There are two significantly different ECM 8000 designs, one with a
>> FET and a transformer and true balanced output, and one with an IC
>> buffer and transfomerless output. I don't recommend disassembling
>> yours to identify it, as the mic element leads are very fine and are
>> exceedingly easy to break. The resistance to ground from pins 2 & 3
>> of a mic I know for sure to be transformerless was about 200 K, and
>> from pin 2 to 3 I measured 330 K with a DVM. I presume that the
>> transformer version would have a far smaller resistance between pins
>> 2 & 3.
> Just measured mine and I get 196K from ground to pin 2 or 3, and 355K
> from pin 2 to pin 3, so I guess I have the one without the
> transformer. Bit sneaky that the box still shows a diagram of a
> transformer coupled output ;-)
Hey, we caught Behringer in a lie. ;-) Oh, I get it, the box is symbolic.
>> I've only seen detailed photos of the transformer version.
>>> I'm going to do
>>> room equalization measurements with the thing, so the freq response
>>> properties are rather important to me.
>> Another thing to remember is that the ECM 8000 rolls off the bass
>> end, with its - 3dB point someplace around 40 Hz.
> Was that for the original transformer version or the new IC version ?
AFAIK, both.
> If that was for the transformer version its possible that the
> transformer itself may have been rolling off the bottom end as well,
> and the IC version may go a bit lower...(one can hope anyway ;)
I suspect that this is the *real* spec sheet for the current version of the
ECM 8000.
http://www.soundfirst.org/audiotoolbox/images/ECM-999_datasheet.pdf
>>> I have no phantom power supply yet, so I can test anything myself.
>>> Can anyone with any experience with the ECM8000 shed some light on
>>> the matter?
>> It's a great mic for the price, and not a bad mic overall. Ken Kantor
>> (senior designer for AR & founder of NHT and Vergence) turned me on
>> to them. I've compared them side-by-side to B&K mics costing about
>> 40 times as much. From 40 to 23 KHz, it's a horse race in terms of
>> frequency response. BTW, Ken recommended using them with Rolls MP-13
>> mic preamps that only put out about 22 volts of phantom power.
> Good to know... definitely seems like a good little mic for the price,
Says a lot about the mic and the price!
> I also made up a transformer based balanced to unbalanced isolation
> and phantom power box using a couple of 9v batteries so I could use it
> with my computer, and it seems to work fine. Pity about the bottom end
> rolloff below 40Hz though. (Although the previous microphone I had
> rolled off below 150Hz so its a definite improvement :)
It's not the only Behringer product with a roll-off like that. Their PEQ
2200 equalizer is -3 at 18 Hz, -1 at 36 Hz. Quiet buggar, though.
> Was Ken referring to the transformer version or IC version ?
Given the time frame, I'd guess Ken was using the transformerless versions.
He said nothing about the rolloff, that's my addition. I noticed it in my
comparisons with a DPA measurement mic and then noticed that it was implied
by some specs I'd seen for the ECM 8000. Ironically, it appears that Ken
was designing a subwoofer with it. I'm sure he knew all about the roll off
and was compensating for it, at least in his mind.
Merlin Zener
> Hi,
>
> Can anyone please tell me if the Behringer ECM8000 requires 48V of phantom
> power to preform according to specs. ( as stated on the freq. response
> graph)
>
> What I'm basically trying to ask is, if I take and build my own phantom
> power supply and it only supply it with lets say 17V, will the mike still
> preform according to what the specs state?
If you go to the Behringer site and download a file called
ECM8000_C_Specs.pdf you'll see it says there: +15V to +48V. So your 17V
should be just fine.
TonyP
> I suspect that this is the *real* spec sheet for the current version of
the
> ECM 8000.
>
> http://www.soundfirst.org/audiotoolbox/images/ECM-999_datasheet.pdf
But one is quoted as 200 ohm and the other as 600 ohm, I wonder if they are
the same or just very similar?
TonyP.
Arny Krueger
news:405963f9$0$31902$afc3...@news.optusnet.com.au
>> http://www.soundfirst.org/audiotoolbox/images/ECM-999_datasheet.pdf
The only way I know to settle that is to buy one of each and compare them
exhaustively. Hardly seems worth the trouble given that the ECM 8000 is as
good as it is, and so readily available.
Ken Kantor
check my mics frequently (we have MB, ACO and B&K references), and I
have not yet seen a Behringer that was 3dB down at 20 KHz. I wouldn't
worry much about it unless you need really "traceable" accuracy.
-k
simon-...@igrin.co.nz (Simon Byrnand) wrote in message
news:<e524ab46.04031...@posting.google.com>...
Arny Krueger
news:a86797f3.04031...@posting.google.com
> I have no idea, but I will open up a few tomorrow. I can say that I
> check my mics frequently (we have MB, ACO and B&K references), and I
> have not yet seen a Behringer that was 3dB down at 20 KHz. I wouldn't
> worry much about it unless you need really "traceable" accuracy.
I haven't seen any down at 20 KHz either, But what about 20 Hz?
Ken Kantor
transformers. To verify, I actually opened one up this evening.
Needless to say, I messed it up, since the wiring is very tight
inside. After I repaired it, I had to re-test its response. (I curse
Usenet, again...) Compared to the reference mic (in this case a
GenRad), it was within 1 dB down to 10 Hz, the limit of my test jig.
I tested a second unit that was identical at the low end. Of course,
the quality and input Z of the of the preamp will make a difference at
the frequency extremes.
I have to say, though, that I haven't bought one of these mics in a
few years, and so I can't be sure the design hasn't changed. Next
time I am in GC, I will pick one up.
-k
"Arny Krueger" <ar...@hotpop.com> wrote in message news:<4rmdnVZxcZh...@comcast.com>...
Arny Krueger
> Based on terminal measurements, none of my ECM-8000's appear to have
> transformers. To verify, I actually opened one up this evening.
> Needless to say, I messed it up, since the wiring is very tight
> inside.
Been three, done that. Mine was transformeless, too. All of mine are less
than a year old. Two are functioning as choir mics.
Here's picture of the elusive?? transformer equipped ECM 8000:
http://www.imagendv.com/altavoces/micro_med.htm
> After I repaired it, I had to re-test its response. (I curse
> Usenet, again...) Compared to the reference mic (in this case a
> GenRad), it was within 1 dB down to 10 Hz, the limit of my test jig.
> I tested a second unit that was identical at the low end. Of course,
> the quality and input Z of the of the preamp will make a difference at
> the frequency extremes.
Still using the Rolls?
> I have to say, though, that I haven't bought one of these mics in a
> few years, and so I can't be sure the design hasn't changed. Next
> time I am in GC, I will pick one up.
When I did my comparison I compared it to a DPA 4007 using the two channels
of a Symmetrix 202, running into a LynxTwo. The
Simon Byrnand
Hi Ken,
> Based on terminal measurements, none of my ECM-8000's appear to have
> transformers. To verify, I actually opened one up this evening.
> Needless to say, I messed it up, since the wiring is very tight
> inside. After I repaired it, I had to re-test its response. (I curse
> Usenet, again...)
Sorry about that Ken...
<points finger at Arny> ;)
> Compared to the reference mic (in this case a
> GenRad), it was within 1 dB down to 10 Hz, the limit of my test jig.
> I tested a second unit that was identical at the low end. Of course,
> the quality and input Z of the of the preamp will make a difference at
> the frequency extremes.
Well thats really good to know. When Arny said they were 3dB down at
40Hz, I was a little bit concerned, but it sounds like this is not the
case. I wonder if the IC version has a bit of active compensation to
flaten out the low end ? (Assuming the capsule needs it...)
> I have to say, though, that I haven't bought one of these mics in a
> few years, and so I can't be sure the design hasn't changed. Next
> time I am in GC, I will pick one up.
Yeah, this all assumes they havn't changed the design again of
course.... I only bought mine about a month ago, but the pins seem to
measure the same as Arny's IC versions so I'm guessing its probably
the same....maybe.... :)
For someone like me who is just measuring/building speakers at a
hobbiest level this Mic would seem to be bargain of the century, as
I've been casually looking around for some kind of measurement mic for
quite a while now, and only stumbled across the ECM8000 *after*
finding the DEQ2496, deciding to get one, and then seeing they had a
recommended microphone to go with it :)
If you do pick up another new one be sure to let us know the
results...(don't open it up though :)
Regards,
Simon
Simon Byrnand
> "Ken Kantor" <k...@aural.org> wrote in message
> news:a86797f3.04032...@posting.google.com
>
> > Based on terminal measurements, none of my ECM-8000's appear to have
> > transformers. To verify, I actually opened one up this evening.
> > Needless to say, I messed it up, since the wiring is very tight
> > inside.
>
> Been three, done that. Mine was transformeless, too. All of mine are less
> than a year old. Two are functioning as choir mics.
Have you had any problems with low frequency feedback ? The ECM8000 is
the first Mic I've tried that when you connect it to a stereo in a
normal room, will actually give feedback at low bass frequencies (like
35Hz etc) *before* it will give feedback in the midrange.
I guess most hand held mic's designed for vocals (including one I was
using previously) simply don't have the extended bass response
necessary to trigger feedback at such low frequencies.
I guess in a choir use you'd have the low frequencies from the mic
rolled off a bit though ?
Regards,
Simon
Arny Krueger
> "Arny Krueger" <ar...@hotpop.com> wrote in message
> news:<IJWdnau3uKa...@comcast.com>...
>> "Ken Kantor" <k...@aural.org> wrote in message
>> news:a86797f3.04032...@posting.google.com
>>
>>> Based on terminal measurements, none of my ECM-8000's appear to have
>>> transformers. To verify, I actually opened one up this evening.
>>> Needless to say, I messed it up, since the wiring is very tight
>>> inside.
>>
>> Been three, done that. Mine was transformeless, too. All of mine are
>> less than a year old. Two are functioning as choir mics.
>
> Have you had any problems with low frequency feedback ?
Trouble? no trouble but I have had take some steps relating to feedback.
>The ECM8000 is
> the first Mic I've tried that when you connect it to a stereo in a
> normal room, will actually give feedback at low bass frequencies (like
> 35Hz etc) *before* it will give feedback in the midrange.
In the room I was working in, the room was singing in the 150 Hz range, but
a little dip with the midrange sweep and the room was more than stable
enough.
> I guess most hand held mic's designed for vocals (including one I was
> using previously) simply don't have the extended bass response
> necessary to trigger feedback at such low frequencies.
True, by design
> I guess in a choir use you'd have the low frequencies from the mic
> rolled off a bit though ?
Not in this case. I put in a dip in the upper bass, and the room was more
than feedback resistant enough. You know how rooms are, YMMV.
Ken Kantor
> "Ken Kantor" <k...@aural.org> wrote in message
> news:a86797f3.04032...@posting.google.com
>
> > Based on terminal measurements, none of my ECM-8000's appear to have
> > transformers. To verify, I actually opened one up this evening.
> > Needless to say, I messed it up, since the wiring is very tight
> > inside.
>
> Been three, done that. Mine was transformeless, too. All of mine are less
> than a year old. Two are functioning as choir mics.
>
> Here's picture of the elusive?? transformer equipped ECM 8000:
>
> http://www.imagendv.com/altavoces/micro_med.htm
This is like a mod-ka-teer artical.
>
> > After I repaired it, I had to re-test its response. (I curse
> > Usenet, again...) Compared to the reference mic (in this case a
> > GenRad), it was within 1 dB down to 10 Hz, the limit of my test jig.
> > I tested a second unit that was identical at the low end. Of course,
> > the quality and input Z of the of the preamp will make a difference at
> > the frequency extremes.
>
> Still using the Rolls?
I only use a Rolls pass-though phantom power box when I want to run
mics directly into my AP. The tests I just cited used the Behringer
Ultragain 2000, the good, pre-tube one. (Input Z is flat at 3K.
>
> > I have to say, though, that I haven't bought one of these mics in a
> > few years, and so I can't be sure the design hasn't changed. Next
> > time I am in GC, I will pick one up.
>
> When I did my comparison I compared it to a DPA 4007 using the two channels
> of a Symmetrix 202, running into a LynxTwo. The
Your sentence cut off. The Symetrix 202 is a decent amp, with a
slightly higher input resistance than my preamp, so I don't know where
your rolloff is coming from. Electret capsules like the ECM-8000
uses, have no trouble achieving flat LF output, if the acoustic input
levels are not extreme. Maybe it is time to re-test your mics???
Ken Kantor
no doubt that the older mics are definately flat enough to do speaker
work. Just get yourself a 1/2" calibrator on Ebay so you can
establish an accurate reference level.
I'll report when I chance upon a newer unit, but I doubt much has
changed.
-k
simon-...@igrin.co.nz (Simon Byrnand) wrote in message news:<e524ab46.04032...@posting.google.com>...
Arny Krueger
news:a86797f3.04032...@posting.google.com
> "Arny Krueger" <ar...@hotpop.com> wrote in message
> news:<IJWdnau3uKa...@comcast.com>...
>> "Ken Kantor" <k...@aural.org> wrote in message
>> news:a86797f3.04032...@posting.google.com
>>
>>> Based on terminal measurements, none of my ECM-8000's appear to have
>>> transformers. To verify, I actually opened one up this evening.
>>> Needless to say, I messed it up, since the wiring is very tight
>>> inside.
>>
>> Been three, done that. Mine was transformeless, too. All of mine are
>> less than a year old. Two are functioning as choir mics.
>>
>> Here's picture of the elusive?? transformer equipped ECM 8000:
>> http://www.imagendv.com/altavoces/micro_med.htm
> This is like a mod-ka-teer artical.
You've lost me. You think this is a one-off mod?
> I only use a Rolls pass-though phantom power box when I want to run
> mics directly into my AP. The tests I just cited used the Behringer
> Ultragain 2000, the good, pre-tube one. (Input Z is flat at 3K.
>>> I have to say, though, that I haven't bought one of these mics in a
>>> few years, and so I can't be sure the design hasn't changed. Next
>>> time I am in GC, I will pick one up.
Buying from GC is IME slow death. Everything takes at least an hour.
Musician's Friend and competitors are more to my liking. It might take a
couple of days of lead time for delivery, but I usually can plan that well.
>> When I did my comparison I compared it to a DPA 4007 using the two
>> channels of a Symmetrix 202, running into a LynxTwo. The
> Your sentence cut off. The Symetrix 202 is a decent amp, with a
> slightly higher input resistance than my preamp, so I don't know where
> your rolloff is coming from.
It may be due to a rise in the mic I was comparing to - the DPA 4007
> Electret capsules like the ECM-8000
> uses, have no trouble achieving flat LF output, if the acoustic input
> levels are not extreme. Maybe it is time to re-test your mics???
I don't have the 4007 anymore - the (corporate) owner wanted it back.
Herb Singleton
k...@aural.org (Ken Kantor) wrote:
> Just get yourself a 1/2" calibrator on Ebay so you can
> establish an accurate reference level.
My 1/2" LD calibrator doesn't fit the 3 ECM8000's I've measured (the mic
capsule was too small). You may need to futz around with the microphone
adapter to fit the Behringer.
--
Herb Singleton
use...@ross-specrtrum.com
Sound & Vibration Measurements
http://www.cross-spectrum.com
Ken Kantor
has been with the plastic GR adapters such as came with the "OmniCal"
1986.
How do your the ECM-8000's look against your (Larsen-Davis, I assume)
standards?
-k
Herb Singleton <use...@cross-spectrum.com> wrote in message news:<usenet3-F1FDA9...@comcast.ash.giganews.com>...
Thomas A
>
> >
> > > I have to say, though, that I haven't bought one of these mics in a
> > > few years, and so I can't be sure the design hasn't changed. Next
> > > time I am in GC, I will pick one up.
> >
> > When I did my comparison I compared it to a DPA 4007 using the two channels
> > of a Symmetrix 202, running into a LynxTwo. The
>
> Your sentence cut off. The Symetrix 202 is a decent amp, with a
> slightly higher input resistance than my preamp, so I don't know where
> your rolloff is coming from. Electret capsules like the ECM-8000
> uses, have no trouble achieving flat LF output, if the acoustic input
> levels are not extreme. Maybe it is time to re-test your mics???
Sorry for jumping in but I am in the process to buy a new mic +
soundcard and have looked at the ECM-8000. Does anyone know if the
frequency response curve presented in the manual is typical of the mic
or does it measure different from that curve? I know that there might
be individual variations between mics, but not how large ones that can
be expected.
T
Herb Singleton
k...@aural.org (Ken Kantor) wrote:
> How do your the ECM-8000's look against your (Larsen-Davis, I assume)
> standards?
I compared them with the TerraSonde ATB's stock Type-2 mic (which in
turn has been measured by a 3rd party calibration lab) using
substitution methods. I've found the ECM-8000's to be +/- 1 to 1.5 dB
from 100 Hz to 10kHz. As with Arny I've found a low-frequency rolloff,
but (as mentioned in this threat) it seems to be dependent on the amp.
The one interesting thing is that even though all three mics were fairly
flat, the response curves weren't consistent. It looks like you can't
just substitute one ECM-8000 for another and expect the same response -
but it will be close.
Arny Krueger
> Sorry for jumping in but I am in the process to buy a new mic +
> soundcard and have looked at the ECM-8000. Does anyone know if the
> frequency response curve presented in the manual is typical of the mic
> or does it measure different from that curve? I know that there might
> be individual variations between mics, but not how large ones that can
> be expected.
IME the Behringer spec sheet is pretty close to reality. We've been
discussing the possibility that there's a roll-off below 40 Hz. If there is
one, it's not problematical. It's a heck of a buy.
Ken Kantor
frequency extremes between samples of the ECM-8000 shouldn't be a big
issue to the amateur speaker builder trying to, say, develop a
crossover. At least that is my opinion. I just love them because
they let me keep my more precious mics off the work bench, away from
spray adhesive, ferrofluid, and welding torches...
I'm not sure what to say about the low end differences we find, other
than mentioning the fact that the mic has a fairly small output
coupling cap. As such, the difference between a 600 Ohm preamp input
and a 3,000 Ohm input could mean the difference between an 8 Hz and 40
Hz rolloff. I'm not saying this is the case, but it is at least
plausible.
-k
Herb Singleton <use...@cross-spectrum.com> wrote in message news:<usenet3-119DF2...@comcast.ash.giganews.com>...
> In article <a86797f3.04033...@posting.google.com>,
Ken Kantor
decided to look into the LF performance of my mics with more accuracy.
I had a tech build a test fixture that can accept standard General
Radio mic calibration adaptors, and which was designed to provide
inherently flat sound pressure (within 0.5 dB from below 10 Hz to
above 1,000 Hz.
Using this method I found 2 ECM8000's that showed a 1 to 2 dB dip in
their response between 20 and 40 Hz! Below and above this range, they
returned to flat. I did NOT see this effect using free-field
substitution against the reference mic. This possibly suggests some
interaction between the capsule venting and the GR-style adapters.
For the record, my best LF calibrated mic (a GR) verified the test
fixture exactly, down below 10 Hz. However, my MB 550 actually showed
an increase below 20 Hz, reaching almost +2 dB at 10 Hz.
I still consider the Berhingers superbly flat compared to the ref mics
(also including ACO and B&K), especially in the free field which how
they will likely be used. However, it was interesting that I was able
to find the reported drop below 40 Hz, however, minor, under some test
conditions.
And I am glad I designed a test fixture I have confidence in at very
low freqs. Thanks for the motivation!!
-k
Herb Singleton <use...@cross-spectrum.com> wrote in message news:<usenet3-119DF2...@comcast.ash.giganews.com>...
> In article <a86797f3.04033...@posting.google.com>,
>
Arny Krueger
>
> Herb Singleton <use...@cross-spectrum.com> wrote in message
> news:<usenet3-119DF2...@comcast.ash.giganews.com>...
>> In article <a86797f3.04033...@posting.google.com>,
>> I compared them with the TerraSonde ATB's stock Type-2 mic (which in
>> turn has been measured by a 3rd party calibration lab) using
>> substitution methods. I've found the ECM-8000's to be +/- 1 to 1.5 dB
>> from 100 Hz to 10kHz. As with Arny I've found a low-frequency
>> rolloff, but (as mentioned in this threat) it seems to be dependent
>> on the amp.
>> The one interesting thing is that even though all three mics were
>> fairly flat, the response curves weren't consistent. It looks like
>> you can't just substitute one ECM-8000 for another and expect the
>> same response - but it will be close.
> Here's some information you all might find interesting (or not). I
> decided to look into the LF performance of my mics with more accuracy.
> I had a tech build a test fixture that can accept standard General
> Radio mic calibration adaptors, and which was designed to provide
> inherently flat sound pressure (within 0.5 dB from below 10 Hz to
> above 1,000 Hz.
> Using this method I found 2 ECM8000's that showed a 1 to 2 dB dip in
> their response between 20 and 40 Hz! Below and above this range, they
> returned to flat. I did NOT see this effect using free-field
> substitution against the reference mic. This possibly suggests some
> interaction between the capsule venting and the GR-style adapters.
> For the record, my best LF calibrated mic (a GR) verified the test
> fixture exactly, down below 10 Hz. However, my MB 550 actually showed
> an increase below 20 Hz, reaching almost +2 dB at 10 Hz.
> I still consider the Berhingers superbly flat compared to the ref mics
> (also including ACO and B&K), especially in the free field which how
> they will likely be used. However, it was interesting that I was able
> to find the reported drop below 40 Hz, however, minor, under some test
> conditions.
> And I am glad I designed a test fixture I have confidence in at very
> low freqs. Thanks for the motivation!!
It seems like the two have you have settled the question of whether or not
the ECM8000 is useable as a subwoofer analysis device.
The answer would be "yes".
That's good news!
ItsTooLoud
tested? Of course, this IS a $40 mic, I don't want to spend a hundred bucks
having it tested...
Paul Andre
Leo Cornole
on this topic, and that I am not bothing you too much with my
questions. One question: once you decide you know the exact mic
reponse, how to you apply the correction when you are using the mic?
Equalizer? Software? Preamp control adustment?
Last question, is the cal curve accurate for very different sound
levels?
Thanks again, and I would be honored by your reply!
Sincerely,
Leo
Ken Kantor
1- How the correction is applied depends on the type of measurement
being made. In most cases, the microphone signal feeds analysis
software and a stored microphone compensation file is applied to the
data before it is displayed.
2- I haven't noticed any frequency response changes that are related
to sound pressure level, provided the microphone is not being
overloaded by SPL's which cause excessive harmonic distortion. If you
need to make accurate measurements at levels over about 110 dB,
however, it is probably best to invest in a "real" condensor
microphone. One of the limitations of inexpensive electrets like the
ECM8000 is their ability to deal with extreme signal levels.
110 dB might seem excessively loud, but it is quite possible if the
microphone is positioned very close to the speaker cone.
-k
"Leo Cornole" <t...@tittcaca.pt> wrote in message news:<bmF6.02295126af697...@1082553292.nulluser.com>...