REW vs SPL Meter + Test Tones?

[dallasstar]

Hi Everyone, I'm new here. I recently bought a subwoofer (SVS 3000 Micro) after many years without one. Thanks to this forum I've recently learned about REW and the Umik-1 microphone. I'm quite interested to try them out, but before I do, I'm curious to know if it's even worth it, given I've already calibrated the sub using a different method I learned the last time I had a subwoofer.

I'm wondering if my own method is equivalent to REW, or if there is something special REW is doing that I haven't already done. Here's the process I followed:

1. I placed the subwoofer in the desired position (not open to moving it, goal is to optimise performance in pre-decided location).
2. I bought an SPL meter (just a regular dB meter, nothing fancy).
3. I found test tones for all frequencies from 15 Hz to 100 Hz (in 5 Hz increments).
4. I played each test tone file, and measured the SPL for each test tone at my listening position.
5. I manually adjusted the crossover (high pass and low pass), subwoofer gain, parametric EQ, phase, slope, room gain correction, etc, until I achieved a flat frequency response up to 100 Hz (same dB measurement at each test tone).

So is REW doing this exact process, and just making it easier? Or is there some additional benefit that it is providing, hence I should still buy the Umik-1? Or perhaps is there some accuracy improvement Umik-1 is providing over a regular SPL meter?

Thank you very much for your help!

 

[dallasstar]

Update: Did some research and learned that my SPL meter is A weighted whereas proper calibration requires Z weighting, which Umik-1 would provide.

 

[DVDdoug]

which Umik-1 would provide.

The "real trick" with measurement mics is that they are calibrated. They come with a file (tied to the microphone serial number) that the software uses to flatten/correct frequency response.

Z-weighting on an SPL meter should be "flattish" but most of the time it won't be good enough for frequency response measurements.




P.S.
USB measurement mics are also calibrated for SPL. With analog measurement mics, the digital level depends on preamp gain so if you want to use it for SPL measurements, you need to do your own calibration with an SPL meter.

 

[MaxwellsEq]

I've seen integration attempted with a calibrated Z or C SPL meter on "slow" used with pink noise, rather than tones. There's always a risk that a specific tone is at a room null.

 

[Speedskater]

Units, aps or programs that use a high tech brief signal will give the transit frequency response.
Sine wave tones will give the sustain frequency response.
Those that use a sweeping sine wave signal will a response somewhere between transit and sustain.
Pink noise signals will give the SPL sound level.