Velodyne Digital DrivePLUSSeries - Manual (Page 14)

4. We set the receiver volume such that we heard a moderate music volume.
5. Our evaluator walked to each initial location and listened. The evaluator took a step in several directions around each initial location to
hear what improvement, if any was heard compared to the initial location. The evaluator chose a final location near each initial location.
6. We placed a small object at each final location so that later we could locate a subwoofer there and could also test these locations
using frequency responses.
7. The evaluator’s observations were as follows:
Location 1: Bass sounded crisp.
Location 2: Bass sounded “hot,” i.e. heavy or boomy.
Location 3: Bass seemed thin compared to Location 1.
Location 4: Bass sounded the same as at Location 1.
Recommended Locations
Based on the above evaluation, we picked Location 1 as the best place for a single subwoofer because it and Location 4 had the best
sounding bass, but Location 1 was closer to the receiver and thus would not require cables to be run around the room as with Location 4.
Also, we picked Location 1 and Location 4 as the best places for two subwoofers because these two locations sounded the same to our
evaluator.
Evaluation by Frequency Response
If you have a microphone and a Digital Drive PLUS subwoofer you can view the frequency response of the subwoofer on one of the visual
interfaces; either a Windows ® computer screen or a TV screen.
In order to use the “Crawl Test” technique:
1. We kept the subwoofer in the same location as described in the Evaluation by Listening section.
2. We connected the microphone to the subwoofer.
3. We played the Auto-EQ PLUS Sweep Tone CD through the audio system.
4. We set the subwoofer volume to its factory setting of 30.
5. We set the receiver volume such that we heard a moderate music volume.
6. We evaluated final evaluation locations as marked in Step 4 of the Evaluation by Listening section by placing the microphone at the
location and looking at the frequency response.
Note: These are the frequency responses without Self-EQ, Auto-EQ PLUS or Manual-EQ of the subwoofer. We want to evaluate the effect of
the placement location, not the effect of optimizing the equalization. The subwoofer equalization will be optimized after its optimal
location is determined.
7. The frequency responses measured are shown below.
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Subwoofer Placement Recommendations Guide APPENDIX A