Response measurement

[MisterB]

I have an RTA mic and REW. I'm curious to know if I correctly understand the process for measuring the response of my subs to create an SPL chart for comparison to other subs. My basic understanding is that I set up my mic 1' away from the sub centered on the driver and then run a sine sweep at 2.83 volts (subs are 8 ohm) with a single sub and measure using REW.

They are not BFM subs so I thought best place to land this would be "everything else".

[CoronaOperator]

You want to do this outside and away from any reflections (nearby buildings, etc). Also, the sub box itself is pretty big compared to the half sphere wavefront at 1 m. At 1m, the half sphere is about 74 cubic feet. Due to the size of your sub box taking up some of that space, errors of 10% or more will occur unless you bury the box in the ground to eliminate the effects of its volume. That is much too much work so most companies measure at 10 m and 28.3 volts. You get the same result but now the area of the half sphere is 74,000 cubic feet. The sub box volume error now is negligible.

[Bill Fitzmaurice]

Measure outdoors, the mic an inch off the ground, at least two meters away. Use enough voltage to get at least an 80dB reading, to mask environmental noise. Extrapolate that to a 1m/2.83v result.