Option 1 Measure The FR of the Subwoofer Only

Chapter 8-3

SV Sound

To set the overall test level, play a 25 Hz frequency and adjust the sub- woofer gain (option 1 below) or the processor master volume (option 2 below) until the SPL meter reads about 75 dB at the listening position.

Run each tone only long enough to get a stable reading from the meter (about 5-6 seconds), and then give the subwoofer about 10 seconds to cool off between test frequencies.

Option 1: Measure The FR of the Subwoofer Only:

To measure the FR of the subwoofer only, connect your sound card out- put directly to a line level input on the subwoofer. Use the Excel spread- sheet named Subwoofer Frequency Response, which will plot the fre- quency response of the subwoofer from 11.2 Hz to 100.8 Hz. Input your raw (direct read) values from your SPL meter into the green band of fre- quencies in the Raw SPL Data worksheet, and the Frequency Response worksheet will plot the FR of the subwoofer.

Below is an example of a subwoofer FR. Notice the large peak from 35- 55 Hz.

To correct a peak such as that above, start by setting the Frequency to about 40 Hz, the Q to HI, and the Level to MAX. Re-measure and re-plot from 30-70 Hz to evaluate the effect.