TOPIC:

It appears that the UMIK-1 has a much lower sensitivity than a "standard" microphone connected to the microphone port of my Mac. Even with the OSX mic level at 100% I still have to do my Fuzzmeasure sweeps at a annoyingly high volume. I am sure something is wrong here.

I also have no clue what to do with the calibration file on my Mac; all your info is only referring to REW.

Any suggestions?

Hi Guus, I have not had a chance to start using the UMIK yet, but WRT the cal file, in Fuzzmeasure Pro you should be able to go Window -> Microphone Calibration -> + button and select the file from there - ?

Hi Guys, I have the same problem with the sensitivity. The mic delivers a very low Level. If I want to measure with ARTA I get a maximum Level of -40dB if i make a impulse-mesurement wihh a normal speaker-loudness.

@ Guus,

The UMIK-1 is tuned for some high SPL so its sensitivity is indeed quite low compared to a microphone where you would manually increase the gain as required. Here it's unfortunately fixed.

There is a way to increase the internal Analog gain by opening the microphone and changing some DIP switches. Note however that it's not very easy if you don't have the tooling. It involves opening the microphone at the bottom which is glued. See the 2 little pins at the bottom? These when rotated will allow you to access the PCB inside.

Feel free to get in touch with us if you need help.

DevTeam

I am running into the same issue as well. How much more gain can be achieved with this microphone and changing the DIP switches? I don't want to tear it apart and find that I still can't get the gain that I need.

Bob S.

You can choose 12,18,24,30dB with 3 DIP-Switches. Which Dip-Switch makes what Gain is decribed on the backside of the microphone-PCB. It's easy. Open the microphone and you will see.
If you change this you have to add the value in your calibration-file in the first line: in my cal-file per example "Sens Factor =-23.07dB, SERNO: 7000461" --> if you choose 18dB with the DIP-Switch (this is for my room-measurtement a good value) you have to change from "-23.07" to "-5.07"

Very good explanation from Jsteinh!
Once you've indeed been able to open the microphone, it's very easy.

Some of the early microphone had that ring glued by mistake so it's not very easy. All latest batch can easily be opened with a simple tweezer inside the 2 holes of the ring at the bottom of the microphone (USB connector side)

Devteam

Thanks for the information guys! I have made the changes. It was really easy. I am using this with REW and the background noise seems very high. Epecially at low frequencies. I waas reading something about this in a seperate thread and based on my serial number I thought was fixed. Since I'm new to REW maybe I just dont understand it yet.

Well, it depends on the amount of gain that you added.. How much gain did you select on the board? +8dB~+12dB is a lot more than enough. More and you're most likely overdriving the input.

DevTeam

No, that wasn't the problem, but your suggestion inspired me to look elsewhere. In REW I had installed the mic calibration file correctly, I had calibrated the soundcard properly but I had NOT calibrated the mic LEVEL properly. I was basically reading background noise levels at very low frequencies. Again, thanks for the suggestions. It got me to the answer in the end.

Glad to hear that you're all set.

Any more details on removing the back (warranty notwithstanding!)???

I'm picking away at the 2 holes at that back, but getting nowhere fast. Does the back pop off or screw out?

Pretty sure mine is glued. Now attempting to DRILL out the 2 holes.

I'm confused -- I have the same low sensitivity issue with my Umik/REW/Mac. If a person changes from what I assume is the standard 12dB factory setting to 18dB by means of the DIP switches, shouldn't they add +6 dB to Sensitivity number in the mic cal file (the difference between 12dB and 18db) and not the whole 18db?

What effect in REW would it have to simply subtract 6dB from the Sensitivity number in the mic cal file?

I am getting blasted out of the room by the volume I need to use to get usable sweep signals level in REW while using the Umik-1.

Thanks!

Steve Z

Steve,

- You can confirm your UMIK-1 gain by its name (i.e. should say 12dB or 0dB depending on the revision)
- You indeed need to edit the sensitivity setting but not that only REW cares (not Fuzzmeasure as per original post of this thread).
- You just edit that text file of the sensitivity by "adding" the dB increment (e.g. Sens factor= XXdB @ 12dB / Sens factory = XX + 6dB @ 18dB).

Makes sense?