Locating a test point

Each of the following tracks produces a low-frequency test tone. The range of these tests is from 100Hz down to 20Hz. The frequency of each test is announced before it begins. The first test is the highest frequency (100Hz); therefore, you will be marking the template from right to left. Each frequency point is listed across the bottom of the Measurement Template (this is called the X-axis). See Figure 16 on the previous page. The vertical scale on the left side of the template indicates relative level, in dBs (the Y-axis). The template’s vertical scale matches that of the RSLM bar graph.

Cue Track 4 and Pause II.

From now on, you will want to keep your CD player’s remote control handy.

Press Play ▼. As Track 4 plays, observe the level indicated on the RSLM.

EXAMPLE:The test frequency is 100Hz and the level indicated is –2dB. Find the intersection of 100Hz (X-axis) and –2dB (Y-axis). Place a dot at that point. See Figure 17.

FIGURE 17

It takes a few seconds for the RSLM reading to stabilize, especially at very low frequencies. Don’t rush. Give each test adequate time for the meter to stabilize.

At the bottom of the bar graph is a green “ON” LED. This LED is illuminated whenever the sound level is below the measuring range of the RSLM. If this occurs during a test, place a dot at the intersection of the test frequency and the bottom frame of the template. See Figure 18.

Indicating an under-range test

FIGURE 18

When finished, press Skip ››l to advance to the next test. Repeat the process described above for Tracks 5 through 26.

When you have completed the 23 measurements, you are ready to analyze the data and make corrective adjustments. The completed Measurement template will look something like the example in Figure 19.

Completed R.A.B.O.S. template

FIGURE 19

Now connect the dots as shown in Figure 20.

This will make interpretation of the data much easier.

Test example with dots connected

FIGURE 20

12 MODULUS II HOME THEATER SYSTEM