Operation | 13 |
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Instruction Manual
ing position to evaluate the sound. Pay particular attention to the deep bass as well as the transition of bass from the subwoofer to the satel- lite speakers.You can also listen to a musical source such as a CD or DVD, with strong bass content that spans the range from deep bass to mid bass (a well recorded jazz disc with someone playing a full stand up bass is always a good choice). It’s usually best not to use a “one note”special effects track like a big explosion or dinosaur stomp- ing to test the subwoofer.Experiment with the position of the PHASE control(s) to get the most extended bass and the best transition from sub to satellites. It should be obvious which is the correct setting. In particular, there will be a smoother more integrated transition be- tween the satellites and the subwoofer when they are properly phased.
Parametric Room Equalizer (EQ)
In order to optimize the performance of your InWall subwoofer the Parametric Equalizer should be utilized. The built in Parametric EQ(s) allow you to select the frequency you want to adjust, and how wide a band on either side of that frequency you’re going to adjust with it. They are designed specifically to remove (turn down) un- wanted peaks in the bass. The procedure is fairly simple: the in- cluded Atlantic Technology/Sencore Test and Training CD is used along with a meter to define the single largest bass peak at the prime listening position and then reduce it with the Parametric EQ.
The test and setup CD also includes a wealth of general information concerning sound reproduction and home theater, in addition to the test tones. Although one set of tones is intended for setting the EQ “by ear” we very strongly recommend using a Sound Pressure Level (SPL) meter or a Real Time Analyzer to set the Parametric EQ.
Adjusting the Parametric EQ Using a Meter or Real Time Analyzer (RTA)
It’s important to complete all the preceding steps regarding speaker setup before setting the parametric equalizer. Once they are com- plete, insert the Atlantic Technology/Sencore Test and Training CD into your CD or DVD player and go to Track 22,which contains bass frequencies from 20Hz to 120Hz. Set the BASS LEVEL of a single subwoofer channel to 75dB at the primary listening position. If you are using an RTA, set it to at least 1/6th octave resolution and slow response. Continue using Track 22 and measure the response of the sub using at least a 1/6th octave resolution (Use slow response to allow the meter to average the standing waves that build up in the room). Chances are that you will find at least one significant peak in the subwoofer’s range (between 20Hz and the crossover point set on the sub or in the processor).Write down the center frequency of the peak, how “wide” the peak is (by noting the upper and lower frequencies where it starts and stops) and how high it is, in dB.
Begin setting the Parametric EQ by adjusting the FREQUENCY con- trol to the approximate center frequency of the peak. Next adjust the WIDTH control to the approximate width of the peak. Note that the WIDTH control is calibrated in octaves.An octave is a doubling or halving of any chosen frequency. For example, if the chosen fre-
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band on either side of the center frequency, depending upon how wide the peak is. Next, set the ATTENUATION control to the ap- proximate
Level Setting Using an SPL Meter
If you only have an SPL meter, set the meter to “C” weighting and “Slow” response then use Track 22 to set the BASS LEVEL to 75dB. Next use Tracks
When setting up a complete home theater we strongly recommend that you use a Sound Pressure Level meter.At the time of this writ- ing Radio Shack® has one that is very affordably priced (approxi- mately $40) and works well. However, for the best result in setting up the levels and the parametric EQ you would be much better served by using a true audio test instrument with a Real Time Acoustic Analyzer (RTA) like the Sencore® SP 295.
To use an SPL meter, turn on your system, put the Processor/Re- ceiver in the Test Mode and set its main volume control to a moder- ate volume level.If the volume control has a 0dB setting with minus dB below and plus dB above 0, set the control to 0dB. Next, sit in the prime listening position, set the SPL meter to the 70dB scale, Slow Response, and C Weighting. Now, holding the meter pointed up and in front of you, let the system cycle its test tone from speaker to speaker. Check the meter and set every speaker (including the subwoofer), to 75dB using the individual level settings in the Pro- cessor/Receiver.You may have to use the Processor/Receiver’s main volume control to get the left front speaker to 75 dB but from then on use the receiver’s internal level adjustments. These are almost always accessible through the Processor/Receiver’s remote control.
As tempting as it may be to set the subwoofer and/or surround speakers higher than 75dB, set them to 75dB and see if you can ac- climate to it.Try watching several different movies and keep in mind that the goal is to have a system that sounds like you’re actually “in the movie.”In most cases, you shouldn’t be consciously aware of the surround output at all.
