Systems ListVelodyneDD18+

Measurement Details

AmplifierClosed Loop
Outside Temperature67 F
Date TestedOct 6, 2011
Settings & Equalization

  • Crossover bypassed
  • Phase at 0
  • Power set to On
  • PEQ filters defeated
  • High pass filter set to the minimum 15Hz 6dB octave setting
  • Night compression off
  • Servo gain set to the maximum of 8


Notes for most of the basic performance of the DD18+ will be covered in the notes for the servo gain 1 versus servo gain 8 test.�

The DD18+ performed flawlessly throughout all of the testing and never got ruffled or made an untoward noise. The EQ and adjustments available by the built in DSP are extensive. The unit performs best with the servo gain set to its maximum and the DD18+ had no trouble with deep bass overload so the high pass filter should be set to its minimum setting to allow it to dig as deep as possible. The frequency response is a little rolled off above 100Hz but this might partly be due to the limitations of servo technology as it does not operate well at higher frequencies. The response in the time domain is solid with no significant issues. The maximum long term output and compression tests reveal that the unit is being EQ boosted centered at 16Hz. This is where compression and limiting of output set in first. The DD18+ has extended output that should be useful to almost 10Hz in room with a room having substantial gain. Looking at the CEA2010 maximum short term output the DD18+ has a large amount of headroom for a sealed subwoofer. It is a tad soft above 80Hz but most people cross over around 80Hz anyway. Interestingly the DD18+ is the first commercial unit to produce a passing 10Hz result, which is not easy to do in an outdoor setting. 86dB spl may not seem like much but room gain can provide 10-15dB spl of gain that low in frequency easily. Again a passing result at 10Hz at all in an outdoor setting is difficult due to the background noise and distortion limit of CEA2010.�

Looking at the results for the EQ system that comes with the DD+ series after double checking it with the reference measurement system , it does not appear to do a very good job compared to manual EQ with a dedicated device. The DD+ series allows 3 options for users to equalize the subwoofer. Manual, Self and Auto. The Self method is least involved and had particularly strange results. The Auto routine did better but still not very good but is slightly more involved. The best method was the manual option but it is the most involved. Still if you are going to use the built in Velodyne EQ I would recommend the manual method. Overall the Velodyne graphs generated in the software looked impressively smooth and linear but looked nothing like what my reference measurement system indicated. The strange thing is that even the major response features appeared to be off or even shifted by 1/3rd octave. Odd indeed.

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Comparable Charts

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