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Some really excellent freeware.


kkantor

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I've downloaded it a few times (author is quite busy issuing updates in response to user's requests). Much can be learned over at diyaudio/speaker forum. There is a couple of threads devoted to this software.

It's extremely flexible to the point that a noob will have trouble using it. The author is in the process of writing a manual.

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  • 2 weeks later...

Just ordered one of these low cost calibrated units for field use:

http://www.cross-spectrum.com/measurement/..._behringer.html

Interesting mic options, particularly the $22 unit. Is it just a Panasonic in a

nice small case? Just noticed - is that "case" an inline phone jack?

http://www.naiant.com/studiostore/microphones.html

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The Dayton equivalent of Behringer ECM8000 was on sale a couple of weeks ago for $35 -- it could happen again:

http://www.parts-express.com/pe/showdetl.c...tnumber=390-801

No, we can't just plug these measurement mics into our computers and be up and running; they are electret condensers which require preamps supplying phantom power.

Not a big deal to make happen, but not so straightforward as some might suppose.... ;)

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Anyone tried this USB mic pre? I can't seem to find a FR spec for it....

16-bit implies 24 kHz max, no?

Nyquist, yada, yada.

[Pete knows this stuff.... :P ]

Oh, YES...measurements.

I'm printing out Curve Junkie Corps membership certificates here.... ;)

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16-bit implies 24 kHz max, no?

Nyquist, yada, yada.

[Pete knows this stuff.... ;) ]

I think you mean 48KHz sampling is good for 24 kHz bandwidth which

is true for a non-realizable brick wall anti-aliasing filter. A guard band

is required in real life and it needs to be wider with inexpensive filters.

Might be 4 kHz so let's say it might be good for 20 kHz but is it 1 or

more dB down? Also, for music it is not unreasonable to have a -3dB

point of 20 Hz or higher, just a matter of bigger coupling caps to correct

if it is not good. I really like my measurement system to be as flat as

possible so that I can run without a calibration curve - just in case I'm

feeling lazy. I like the cal curve to just touch up the response to trim

it up by a dB or less.

Also, there's often AC line voltage coupling in Lap Top analog circuitry

so it is good to get as much LF signal in to improve the SNR.

We think we have the ECM-8000 schematic here, but I think there are

some mistakes as I comment in the thread:

http://www.diyaudio.com/forums/multi-way/1...ment-mic-7.html

Samples seem to be between 3 to 5 dB down at 20 Hz.

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I picked up one of these MXL Mic Mates and did a quick check of the

frequency response, seems that it is -.25 dB at 20 and 20 kHz -

completely flat in between as would be expected. Quite good enough

for measurements. Seems to be a lot of LF noise, not sure if it is the

MXL or something else.

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I picked up one of these MXL Mic Mates and did a quick check of the

frequency response, seems that it is -.25 dB at 20 and 20 kHz -

completely flat in between as would be expected. Quite good enough

for measurements. Seems to be a lot of LF noise, not sure if it is the

MXL or something else.

I bought one to try to use for measurement work. But, I found the overload level to be too low for NF work, and the "pad" switch to have almost no effect on it. (Changed gain, but not O/L.) I'll stick with my Tascam for now. I think the MXL could work if one only did >1M work. (I can't seem to turn off the phantom power. Probably not a big deal, but silly.)

Also, Shure has a similar unit that I haven't had a chance to try yet.

-k

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I bought one to try to use for measurement work. But, I found the overload level to be too low for NF work, and the "pad" switch to have almost no effect on it. (Changed gain, but not O/L.) I'll stick with my Tascam for now. I think the MXL could work if one only did >1M work. (I can't seem to turn off the phantom power. Probably not a big deal, but silly.)

Also, Shure has a similar unit that I haven't had a chance to try yet.

-k

Thanks Ken, yes the switch seems to be about 3dB per step from

a casual check. I just want to use it for RTA in room measurements,

full measurements would have been nice but not required. It shows

up as a generic USB device and at least the first time I tried it quickly,

I got no control panel for it in SYNRTA - it did work, just could not

change the gain. I'll have to see if I need a better driver or some

other software.

I might make an XLR cable that allows the MXL to power the Mic, then

also tap off the signal and bring it into an M-Audio Transit which has

enough gain on the line in for most work with these high output

electrets.

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  • 3 weeks later...

I found the MIC-MATE to be too noisy with cheap build quality.

The EMU-0202 gets an excellent review here, however it does

not provide phantom XLR mic power:

http://www.libinst.com/EMU%200202%20USB.htm

I see that the EMU-0404 does provide phantom power and

would hope that it has at least as good performance:

http://www.emu.com/products/product.asp?ca...p;product=15185

These have an option for 192K sampling rate - excellent!

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  • 2 months later...

Here is another interesting piece of freeware:

http://www.tolvan.com/edge/

It simulates the 4pi to 2pi conversion of a speaker on a finite baffle. Calculates edge diffraction (reflections), if you will.

Real easy to run, you define the front baffle rectangle and then place a driver of any size at any location on that baffle. You can even add multiple drivers and do some crude line array simulation that way.

Fun to play with.

David

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Here is another interesting piece of freeware:

http://www.tolvan.com/edge/

It simulates the 4pi to 2pi conversion of a speaker on a finite baffle. Calculates edge diffraction (reflections), if you will.

Real easy to run, you define the front baffle rectangle and then place a driver of any size at any location on that baffle. You can even add multiple drivers and do some crude line array simulation that way.

Fun to play with.

David

Nice!

If you get time, have a look at the following:

http://www.classicspeakerpages.net/library..._public_dom.zip

It's an application we developed at Jensen to do similar things. I eventually released it into the public domain. It's showing its age, in terms of the interface and OS compatability, so I'm glad new tools are emerging.

-k

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