Which Omni Mic to get?

[Glenn Kuras]

A lot of people keep saying the ECM8000 is great as well as the dbx RTA-M. I can't really seem to find frequency response charts easily for omni's which I think is weird

Most omni mics are flat enough to do useful room tests. I would just go on price.
For test Room EQ Wizard Tutorial - GIK Acoustics

[adamboon]

As mentioned almost any omni will do for analysis, however if you buy a slightly nicer one, you might also be able to use it for recording. Line Audio OM1 is a killer, I also like our Sennheiser K6 omnis. Oktava 012 omni would be another option. Also the modular 3 Zigma stuff looks amazing

[DanDan]

The Dayton EMM6 and the MiniDsp UMIK-1 come with an individual Calibration File specific to that mic. These files make both close to scientifically flat when pointed directly at the source of interest.
EDIT +1 adamboon, the DPA4060 is an amazingly useful studio mic.

DD

[Scott Whigham]

Ethan Winer posted this a while ago - RealTraps - Measuring Microphones

Even inexpensive omni condenser microphones are quite flat at bass frequencies - what separates the men from the boys is how high their response extends, and how flat they are above 1 KHz. We tested to only 20 KHz, though I imagine some of these microphones are useful to even higher frequencies.

... From this data it appears that for measuring loudspeaker setup and room treatments, the $40 Nady or $50 Behringer are quite adequate - within a few dB of the most expensive options - and far better than the Radio Shack SPL meter which is often recommended.

I have the ECM8000 FWIW.

[JoshMoose]

Hey everyone thanks for the helpful replies! I checked out everyones links, cool stuff you all are doing!