We have a number of inquires from time to time about what to use for measurement on a budget- most folks aren't in the market for an HP preamp and a Bruel & Kjar mic! And I wanted to have something inexpensive to carry around with my laptop, too.
After trying out a few different mic's and preamps, this is what we've settled on for "budget measurements":
This is a Behringer ECM8000 omni room test mic (~$35), combined with an M-Audio DMP3 dual channel analog mic preamp (~$200). Yeah, I think the back lit VU meters are kinda cool in a retro sort of way, too! Clip LED's are inlcuded which flash -4dB below the actual clip point. The DMP3 has 48V phantom power for the microphone, and also has a pad as well as gain control when using with high level signals. This preamp has gotten very good reviews from some of the semi-pro music magazines; apparently they have a very nice transformerless balanced circuit that compares well in sonics and noise rejection with units costing 5X to 10X.
Output is a balanced tip-ring 1/" phone plug, which can be safely operated with the low balanced side grounded. Here, I'm using a colorful cable with balanced tip-ring plug from Rat Shack, (sorry Lex, didn't see one in Cat Cables , and a 1/4" phone to phono adapter, also from Rat Shack. The actaul mic cable is also a Rat Shack special, just to round things out.
How good is it? Surprisingly good. In the LF area, it tracks my B&K perfectly- this is the ideal setup for the home brew sub builder. No more Rat Shack SPL meter and compensation curve XL sheets! In the HF, it's a bit soft above 15 kHz, down about 3 dB at 20 kHz. So, it's not the tool to compare and evaluate which tweeter is flattest to 22 kHz, though with a simple calibration file, I might even take back that caveat. Below that range, it is disgustingly flat, (considering the $35 mic price). The mic also comes with a stand adapter and a nice foam lined carrying case. Workmanship is about a bazillion times better than most of the budget mic's I've seen.
Here's an example measurment made on the MkIV version of the M8's, showing the nearfield driver and port output below 200 Hz, after adding a little more stuffing to the cabinet, to get a slightly over damped characteristic (curve is closer to a bessel HP, and works better closer to the wall, without "boom").
Note softening of driver null at box tuning of 32 Hz, and centering of port output. This is a swept sine measurement; the output at 32 Hz was palpable at the listening location. :B
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
After trying out a few different mic's and preamps, this is what we've settled on for "budget measurements":
This is a Behringer ECM8000 omni room test mic (~$35), combined with an M-Audio DMP3 dual channel analog mic preamp (~$200). Yeah, I think the back lit VU meters are kinda cool in a retro sort of way, too! Clip LED's are inlcuded which flash -4dB below the actual clip point. The DMP3 has 48V phantom power for the microphone, and also has a pad as well as gain control when using with high level signals. This preamp has gotten very good reviews from some of the semi-pro music magazines; apparently they have a very nice transformerless balanced circuit that compares well in sonics and noise rejection with units costing 5X to 10X.
Output is a balanced tip-ring 1/" phone plug, which can be safely operated with the low balanced side grounded. Here, I'm using a colorful cable with balanced tip-ring plug from Rat Shack, (sorry Lex, didn't see one in Cat Cables , and a 1/4" phone to phono adapter, also from Rat Shack. The actaul mic cable is also a Rat Shack special, just to round things out.
How good is it? Surprisingly good. In the LF area, it tracks my B&K perfectly- this is the ideal setup for the home brew sub builder. No more Rat Shack SPL meter and compensation curve XL sheets! In the HF, it's a bit soft above 15 kHz, down about 3 dB at 20 kHz. So, it's not the tool to compare and evaluate which tweeter is flattest to 22 kHz, though with a simple calibration file, I might even take back that caveat. Below that range, it is disgustingly flat, (considering the $35 mic price). The mic also comes with a stand adapter and a nice foam lined carrying case. Workmanship is about a bazillion times better than most of the budget mic's I've seen.
Here's an example measurment made on the MkIV version of the M8's, showing the nearfield driver and port output below 200 Hz, after adding a little more stuffing to the cabinet, to get a slightly over damped characteristic (curve is closer to a bessel HP, and works better closer to the wall, without "boom").
Note softening of driver null at box tuning of 32 Hz, and centering of port output. This is a swept sine measurement; the output at 32 Hz was palpable at the listening location. :B
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
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