Dayton mic plus audiotools app
I recently got the iMM-6 iDevice Calibrated Measurement Microphone, and the app to accompany. Just under $30 all up, and works well. I recommend it.
The biggest catch, I found, is this:
It took me some time to realise this because I was initially testing small (10cm) wideband speakers, which all have a somewhat peaky response 5-10 kHz, so they look wonky on either test :)
The biggest catch, I found, is this:
- an ideal system measures flat on PINK noise when using the octave views (1, 3 or 6 bars per octave).
- an ideal system measures flat on WHITE noise when using the full resolution.
It took me some time to realise this because I was initially testing small (10cm) wideband speakers, which all have a somewhat peaky response 5-10 kHz, so they look wonky on either test :)
Above is a nearfield graph of a single wideband driver, a 12cm shielded 16ohm speaker from a Phillips TV, in a rough test box*. Note the broad rise in mid HF.
Below is a big coaxial in a good box. No serious problems, the largest dip is around 300Hz.
Both of these are measured with PINK noise.
Below is a big coaxial in a good box. No serious problems, the largest dip is around 300Hz.
Both of these are measured with PINK noise.
Last, I've overlaid a full resolution plot of both, measured with WHITE noise.
I forgot to keep the conditions identical (the blue trace is a quick handheld recording of my full system, measured at the listening position), but it is still obvious how the line graphs match the bar graphs, despite being captures of different input signals.
*The Phillips drivers look like basic round TV / radio speakers, but they sound better than most.