emm-6, weird result(?)

[hybris]

Hi, I recently ordered the emm6 calibrated mic from cross-spectrum labs, and my goal was to use this to measure in room frequency response via my laptop and REW.

First of all the sensitivity of the mic seems very low, should I have some mic preamp or something in between the mic and the laptop?

anyhow, I tried without it, and had to record at -20dB (not -12dB as is default) to be able to calibrate the output/input level without turning up the system so loud I was afraid of blowing my speakers.

I've also calibrated the soundcard (it was almost perfectly flat), and made a .cal-file for the microphone based on the measurements that were included on a paper with the mic.

The resulting graph is slightly baffling to me, this can't possible be correct?
I know I have a large room resonance at about 50hz (that is corrected with EQ when I play music), but the wide dip between 2-8khz and large boost at 10-20khz doesn't really make sense to me.

I have a relatively high noiselevel that seem to come from the laptop somehow (perhaps due to maxing volume and gain on the mic), I don't know if that can be adding to the signal and creating this effect?

Any suggestions of what I may be doing wrong here?

The graph has 1/12 octave smoothing

[brucek]

First of all the sensitivity of the mic seems very low, should I have some mic preamp or something in between the mic and the laptop?

The mic is a condenser mic and always requires a preamp to bring the level up to line level before plugging into your soundcard. The preamp supplies the correct gain required and also supplies the 48 volt phantom power to turn on the electronics in the mic.

Many members here use the Behringer XENYX 802 preamp.

If you're using a laptop, they generally don't have a line-in available (although some do), so you'll require an external USB soundcard to use with REW.

Any measurements you have taken with the mic without a preamp are not meaningful, I'm afraid...

brucek

[hybris]

brucek wrote:

The mic is a condenser mic and always requires a preamp to bring the level up to line level before plugging into your soundcard. The preamp supplies the correct gain required and also supplies the 48 volt phantom power to turn on the electronics in the mic.

Many members here use the Behringer XENYX 802 preamp.

If you're using a laptop, they generally don't have a line-in available (although some do), so you'll require an external USB soundcard to use with REW.

Any measurements you have taken with the mic without a preamp are not meaningful, I'm afraid...

brucek

Thanks, that's what i suspected. My laptop have a line in, but i need the preamp then. Humm. Thank you for your quick reply.