Can I use this Mic?

[ROBSCIX]

I have a Shure mic in which I can get the Fequency response graph from the Website is it possible to use this micrphone with REW?

[brucek]

If you can get a calibration file and it has a line level output, then it can be used.

[ROBSCIX]

well I have a mixer so I can bring the mic to line level and above easily. I don't have a calibration file but figured I may be able to make one becasue I have a response graph of the micrphone from the manufacturer. Can I make a calibration file from this?

[brucek]

Can I make a calibration file from this?

Yeah, if it's resolute enough to get values off.
Pick a frequency value to be the zero point. i.e 1000Hz. and then construct the file from there as to how far below zero (or above each frequency might be). REW will interpolate the missing data between the points.
i.e.
20.00 -15.00
25.20 -12.00
31.75 -10.00
40.00 -5.00

etc....... well you get the idea.
Any values above the file, REW will extend.

Save the file as a meter.cal file...

brucek

[mace]

brucek wrote:

Yeah, if it's resolute enough to get values off.
Pick a frequency value to be the zero point. i.e 1000Hz. and then construct the file from there as to how far below zero (or above each frequency might be). REW will interpolate the missing data between the points.
i.e.
20.00 -15.00
25.20 -12.00
31.75 -10.00
40.00 -5.00

etc....... well you get the idea.
Any values above the file, REW will extend.

Save the file as a meter.cal file...

brucek

If you have a Mac you can use this nice program called GraphClick from: http://www.arizona-software.ch/

I'm sure there are PC equivalents as well.

Later,

Mace

[ROBSCIX]

Yeah, Actually alot of micrphones will have a frequency response graph avaialble for their mic's so this would be a good aaplication to have around. Does anybody know of a app similar to this for windows? I am surprised you guys don;t hava thread with different mic's and the Calibration graphs to go with them..

[brucek]

Yeah, Actually alot of micrphones will have a frequency response graph avaialble for their mic's so this would be a good aaplication to have around. Does anybody know of a app similar to this for windows? I am surprised you guys don;t hava thread with different mic's and the Calibration graphs to go with them..

Well, there are several reasons why we don't.

We presently recommend the Behringer ECM8000 microphone with preamp or the Galaxy CM-140 SPL meter. We have calibration files available for them both on our downloads page.

Equalization of subwoofers (which is what REW is used for mostly) require microphones (or very good quality SPL meters) to be able to accurately extend down to 5Hz.

Many microphones are specifically tailored for voice and don't extend that low (I suspect your Shure is that way). Even when they do extend to very low frequencies, (such as in the case of the ECM8000 microphone), they require calibration professionally to get the values needed for the very low frequencies. Generally what the manufacturer will supply wouldn't be of much use in that regard.

Below is the specification graph supplied by the manufacturer for the ECM8000. It extends to 60Hz.
Below that is the professionally calibrated results graph shown to 5Hz of the cal file we provide when fed into REW software.

Do you feel that any graph software could pull the calibration file from that specification graph? See the problem?

SPECIFICATION GRAPH.
ecm8000_SPEC.jpg

ECM8000 PROFESSIONALLY CALIBRATED TO 5Hz.
newecm8000.jpg



brucek

[ROBSCIX]

No, not given the resolution of the graph. I see the problem. I was just interested in using this application with the gear I have that's all. I guess I can't.

[brucek]

It really depends on what you want to use REW for. If you want to test your subwoofer down to 20Hz for example and had a specification graph that went that low with enough resolution to create some data points, then it would be fine.

brucek

[ROBSCIX]

I thought it was for balancing the output of your speakers but now after reading alittle more I see it is not. Flat response is alot not really what I am looking for aswell according to other info I read. What about a personal HT system using a PC. 22" LCD screen full 5.1 surround sound DD.DTS..etc. How would one go about setting up this simple system for optimal sound?