Measurement mics

[pinkmouse]

You will need a seperate preamp for the ECM, the "phantom power" that the card puts out is likely around 1.5V. Real phantom power is spec-ed at 48V, but can wander down to about 30V with no real problems.

[Ron E]

Sound Card mic bias is 5V, from 5V supply in the computer power supply., so it is perhaps +/- 0.3V.

My experience with panasonic capsules driven by the sound card (3 different ones) is that they are very noisy with quite a bit of hum, but that would depend on the sound card, I suppose.

I spent $50 and perhaps 15 hours all told shopping for the parts and building a wallin mic and preamp, just to have the output be noisy, distorted and barely useable. If I had an oscilloscope, I would have tried to fix it.....

I bought a Behringer ECM-3000 and UB-802 and 20' cord for $80 complete, and I never looked back. Worked the first time and every time since with no fiddling.....Trying to save $30 by DIY was a waste of $100's of dollars of my time.

[Hertzschmerz]

you might be talking about the DIY measurement mic in the ESP pages.

No, I meant http://www.friedman.purespace.de/Mic.htm . The author had used exactly the same Sennheiser capsule which I suggested. Unfortunately his site is dead. You can find the text parts from his page by copying the URL above into the "take me back" box at http://www.archive.org

[Behringer ECM 8000]

One problem with these microphones is that their real frequency response may deviate considerably from the plot in the Behringer specs. You can see an example at the already mentioned site http://www.ele.tut.fi/~artoko/audio/...crophones.html . No problem if you have access to a calibrated mic in order to record a correction file. Also no problem if you only need a tool for analyzing your crossovers.

If the responce of the mic is flat between 200 and 15000hz it will be ok since measurements below 200 hz will be very inacurate (or you need to measure it openair). Just simulate the bassresponse and take that grafic and add it to the grafic you measured with the mic. This will give a more realistic result.

I don't agree here. Nearfield measurements deliver accurate results in the lower frequency regions and are a useful instrument to examine bass alignment and low frequency cabinet resonances. But frequency response below 200 Hz is not a problem with most electret microphones. In contrast, I found major problems above 5 kHz (mostly sudden drop-offs) with cheap (fake?) Panasonic capsules.

[rcavictim]

RonE,

Your solution sounds practical. I agree about one's tiime being too valuable sometimes. I assume the UB-802 is not a German U-Boat. What is it please?

[audio-kraut]

One problem with these microphones is their real frequency response may deviate considerably from the plot in the Behringer specs

funny enough - the behringer microphone response is one of the better ones, and behringer includes a test sheet with each mike.

New massproduction since app. 1900 guarantees with included quality controls sufficiently small deviations of each produced item from the specifications of the lot.

With these curves it is possible to correct the measured frequency response of the object under test.

Just because something is cheap - and I gather from knowing my former countrymen - idoes n ot mean something is junk.

I refer here i.e. to some japanese produced items that in my opinion fulfill that role at 350k$ to a much greater extend. (wavec amps)

[Hertzschmerz]

behringer includes a test sheet with each mike

This is new to me. Haven't seen such a sheet with the one i got.

Just because something is cheap - and I gather from knowing my former countrymen - idoes n ot mean something is junk.

Looks like you haven't been here for a while - "Geiz ist geil" is the current philosophy.

[Zero Cool]

There is an inexpensive Audix mic, the TR-40 that is about $145.00 US that last time i priced it, that is pretty good.

Personally i use a Earthworks M-30 that i purchased used for about $300.00

You can go to the www.siasoft.com website and take a look at all the mics there for use with the SMAART software.



Zero

[bombardon73]

Hertzschmerz, I somehow agree with you when you do low frequency measurements in nearfield (only a few centimeters).
But when you do the regular measurements (1meter distance) and use your living room the results will be inaccurate.

Wonder why Visaton has a measurement room of 7x7x7meters?

And if you see the loudspeaker measurements in Klang&Ton (german magazine) you'll notice that e.g. 8" bassspeakers have the same dip around 125hz. This is because of the room they measure in.

Thats why I would choose to simulate the bassresponse with some good software because bassresponse is more like a "mechanical" thing and is therefore very predictable when simulated.

As for the Mic, I think I'll buy me a Behringer. It seems it's more then worth the money!

[audio-kraut]

Looks like you haven't been here for a while

Pretty nigh on 25 years.

But - geiz ist geil kenne ich schon - apologies to the non germanic people here.

You are right - the sheet I got is the one published on their website. But I still maintain that under todays production conditions individual
deviations from the "lot" performance can and are held to a negligable minimum - otherwise one could sue behringer far false advertising

Anyway - for the purposes i use mine for it is quite sufficient - i.e. room response, delay and phase.

[Ron E]

Originally posted by rcavictim
RonE,

Your solution sounds practical. I agree about one's tiime being too valuable sometimes. I assume the UB-802 is not a German U-Boat. What is it please?

It is a Behringer preamp with phantom power. It is a good match for the Behringer mic and you can use it for karaoke parties if you get bored ;-)

"Geiz ist geil" kenne ich nicht. Trying to come up with a literal translation I get "greed is great" or "desire is luscious" or something like that. Ich weiss das der wort "geil", hat verschiedene meinungen, die haengen auf der zusammenhang. Geil was a replacement for "cool" or "super" or "Toll" when I was in Muenchen many years ago.... I only heard it used in the sense of the word "randy" as used by the English when I lived in Oesterreich, however....