DIY Sub Graphs

[Josuah]

Maybe this is the first real REW 4.0 graph posting. Here are my measurements of the sealed sonotube subwoofers I built a while back. For those who didn't follow the earlier thread (I've also posted the graph there as well) these are four 15" TC-2000 SVC drivers in two 20" diameter 4' high sonotube enclosures powered by a Behringer EP2500 and boosted/filtered by a Behringer DCX2496.

I used an ECM8000 with Sonny's calibration file, extrapolated to -12dB at 5Hz.

Thanks, John, for building this program that let me reliably calibrate my subs. I guess the donation I made back on version 3.0 did help a little.

[brucek]

I used an ECM8000 with Sonny's calibration file, extrapolated to -12dB at 5Hz.

I don't really think you can rely on that as being very meaningful. Extraploation usually only works with a linear function - which the mic response surely is not.
How do you know the mic doesn't quickly go to zero below 10Hz? (which it likely does). I would restrict the measurement to 10Hz....

Generally, to keep consistent, we post graphs with a vertical axis of 45dBSPL to 105dBSPL. It allows everyone to compare apples to apples....

**** good response though......

brucek

[Sonnie]

Yeah... for looking at the sub... I'd use the default axis limits, except maybe extend the lower end to 10Hz if you want, but cap the top at 200Hz. This will give us a better comparison of what the sub is actually doing.

[Josuah]

The -12dB was based on some subjective testing (what do I expect that sound passage in the movie to feel like) and responses from the same person that Sonny sent his mic to for calibration.