Infinity Model Twelve manual Level, What You Measure, What to Do, Example 1. Single Dominant Peak

The pointer on the slider will indicate the correct width setting. Enter this number in the Width field of the Measurement Template. In our example, the width is 12.5%.

It is not realistic to expect a perfect fit. Acoustic measurements encompass the behavior of not only the speakers but of the room and its contents as well. Reflected energy, standing waves and ambient noise all add their part. Determining the best width setting nearly always requires compromise.

Level

This setting will define the amount (level) you want to reduce the peak, in decibels.

The R.A.B.O.S. level adjustment is limited to attenuation only, and is adjustable from 0dB to –14dB. After optimization, the R.A.B.O.S. equalizer will eliminate the largest low-frequency peak; therefore, the broadband bass level can be increased without overpowering the midrange frequencies. R.A.B.O.S. applies this compensation automatically.

You will use the Width Selector as an aid in determining the correct level setting. Place the Width Selector as described above and adjust it to the correct width. Observe the first frequency point on the high-frequency side of the peak that no longer follows the slope of the Width Selector. In this example this is 56Hz. Calculate the average level of the readings from 56Hz up to 100Hz; that is, 10 data points in this example.

56Hz	63Hz	66Hz	72Hz	77Hz	80Hz	85Hz	90Hz	95Hz	100Hz	– 92 ⎟ 10 = –9.2
–9	–10	–8	–9	–10	–9	–8	–10	–10	–9

Whenever your answer has a remainder, always round down (disregarding the negative [–]) to the next whole number.

In our example, you would enter 9 in the attenuation field.

This may not be the best method in all cases. The next section contains several other examples.

What You Measure, What to Do

As stated earlier, it is not possible to anticipate the effect of every possible listening environment. However, most residential sound rooms share many characteristics, and their dimensions fall into a range that make some response irregularities far more likely than others. On the following pages are examples of what you may encounter. Following each example is a strategy for correction. Compare your measurement results with the following examples. Find the one that best fits your graph and follow the instructions presented for that scenario.

Remember, when looking for a match, look at the descriptive characteristics, not any specific frequency or level. Each of these examples can occur at any frequency, bandwidth and level. It is unlikely that your test results will be exactly as depicted in these examples.

Example 1. Single Dominant Peak:

Figure 15. Single dominant peak

This is the most common result of speaker/room interaction.

Apply the Width Selector as described in Figure 13. Align the center-line of the Selector over the center of the peak, as shown in Figure 14. Now adjust the Selector until you have achieved the “best fit.”The slider now points to the correct bandwidth setting. In this example, the frequency is 43Hz and the best-fit width is 12.5%. Fill in the Width and Frequency fields provided on the template.

Determine the appropriate level using the technique described earlier. In this example, –9dB would be best. Enter the level in the field provided.

Skip to the “Adjusting the R.A.B.O.S. Equalizer”section on page 14.

11 Cascade Model Twelve