Which is the more conventional / useful format when discussing such things? The Faber Acoustical iPhone meter gives the choice of A, C or Flat for Weighting, LP or LEQ for Level Type, and Fast, Slow or Impulse for Response. I've tended to use Flat, LP and Fast since getting the app.
I'm not familiar with the Faber Acoustical App, I've read what's on their web site, that's all.
What method of measurement depends on what one wants the measurements for. To see how loud one's playing music, I would use flat and fast, not sure what LP means, but I wouldn't use LEQ as that's a different function.
If I was doing a health&safety assessment on factory noise, then LEQ is the measurement required as, effectively, it measures noise dosage so takes into account how loud and for how long, as long-term hearing damage depends on both actual loudness and length of exposure.
If I was doing a room EQ adjustment, then I would use flat and slow, as I would want short-term variations in the noise being used as a test signal to average out.
If I was measuring impulsive noise, say off drums or gunshots, to make sure my microphones weren't being overloaded, then the Impulse setting would be appropriate.
Note that even Faber themselves say that their meter could be up to 6dB out based in the variation in sensitivity of the microphones in the 'phones, so if one wants to do any absolute measurements, rather than relative, the microphone will need calibrating. I would also suggest that the frequency response of the internal microphone isn't good enough for anything other than relative measurments without caibration. I certainly wouldn't want to set up an active electronic crossover with an uncalibrated microphone.
S.