Welcome, Guest
Username: Password: Remember me
Here is the place to share your questions/comments about your setup of the UMIK-1 USB measurement microphone


NOTE: This is a "Community" forum. Please be mindful that community members are here to help as part of a community effort. We therefore appreciate your effort in keeping this forum a happy place!

If you have a specific issue (e.g. hardware, failure) and want help from our support team, please use our tech support portal (Support menu - > Contact Us).
Thanks a lot of your help in making a better community.
  • Page:
  • 1

TOPIC:

UMIK-1 REW RTA negative readings 2 years 3 weeks ago #49067

  • normva
  • normva's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 3
  • Thank you received: 0
Hi,

I recently bought UMIK-1 and I am noticing some strange things in the measurements. My REW RTA readings are negative starting from 900 Hz. This does not seem normal to me. Shouldn't the lowest dB be around 0? The attached picture is taken in quiet room, only PC fan is running. The calibration file is loaded (705-8046).



What could cause such readings and how to fix it?

Thanks in advance.
Attachments:

Please Log in or Create an account to join the conversation.

Last edit: by normva.

UMIK-1 REW RTA negative readings 2 years 2 weeks ago #49275

  • normva
  • normva's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 3
  • Thank you received: 0
Anyone?

Please Log in or Create an account to join the conversation.

UMIK-1 REW RTA negative readings 2 years 2 weeks ago #49280

  • Ultrasonic
  • Ultrasonic's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 2091
  • Thank you received: 418
dB is a relative scale and so negative values are entirely possible. It's not that 0 dB is 'no sound'.

I can't remember what typical background levels look like though as I haven't made a measurement like this in ages, so I'm not sure if what you're seeing is sensible or not. My gut feeling is that it is.

What sort of levels do you get if you make a measurement when playing music at normal volumes?

Please Log in or Create an account to join the conversation.

UMIK-1 REW RTA negative readings 2 years 2 weeks ago #49282

  • Ultrasonic
  • Ultrasonic's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 2091
  • Thank you received: 418
I thought I'd stop being lazy and plug my UMIK-1 to see what a noise spectrum looked like. Below is a result with no averaging. What this looks like is dependent on other settings too but overall I suspect that there is nothing wrong with what you measured.

Attachments:

Please Log in or Create an account to join the conversation.

Last edit: by Ultrasonic.

UMIK-1 REW RTA negative readings 2 years 2 weeks ago #49283

  • normva
  • normva's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 3
  • Thank you received: 0
Thank you.
I can now get some peace of mind.

Please Log in or Create an account to join the conversation.

  • Page:
  • 1
Moderators: devteam