Velodyne EQ-Max 15 Subwoofer Review Measurements and Analysis
The EQ-Max 15 subwoofer was measured outdoors sitting directly on the ground on its side with the M30 microphone placed 2 meters from the front edge of the corner of the cabinet with the grill removed. The driver and ports were equidistant from the microphone. The LFE input was used so that the internal low pass filter was disabled, the phase was set to 0 and the subwoofer volume was set to maximum. The Jazz/Classical EQ pre-set was used as it had the flattest basic response. All tests were conducted in this configuration, except for those tests purposely conducted to examine the effects of the built in functions or different operational modes.
The overall approach to this testing along with the equipment and software used is outlined in the article here.
Editorial Note on Enclosure Orientation for Outdoor Measurements:
There has been some concern expressed by Velodyne that the orientation used for the ground plane measurements may have compromised the EQ-Max-15’s performance. The EQ-Max-15 subwoofer is designed to have the down firing ports in close proximity to a boundary for proper loading and that the rumble filtering and limiter circuits are tuned to the subwoofer operating in this manner. To explain a little further…When a port is placed in close proximity to a boundary it changes the effective air mass of the port which lowers the system tuning some. This in turn impacts the driver excursion with frequency profile and also system response shape, sensitivity and efficiency. Placing the subwoofer so that the ports are firing to the side not loaded into a boundary as per the orientation for the measurements here, would increase the tuning frequency a little which would have some effect on the overall system performance. What would likely be seen is slightly higher output in the upper bass with lowered distortion and slightly diminished low end output with increased distortion. The tuning shifting up slightly allows less driver excursion above tuning and increased driver excursion at the low end as it unloads from the tuning at a higher frequency range prior to the rumble filter. Knowing this, why was the EQ-Max-15 tested in this orientation? Whenever I set-up to measure a subwoofer with multiple radiation points outdoors the first thing that is done is a few investigative measurements with the subwoofer in various orientations in order to determine which produces the flattest most extended and powerful output. The EQ-Max-15 was measured in both down firing and a diagonal orientation as used for the measurements presented here. The resulting measurement showed the EQ-Max-15 to have virtually the same response shape either way and to have slightly higher output levels and lower extension in the configuration it was ultimately measured in. This is shown in the measurement graph below.
The second reason for choosing this orientation for measurements of the EQ-Max-15 is that it is what is shown for a subwoofer of this particular geometry in the official CEA-2010 document. Quoted from section 4.2 note D. of the official document.
“A DUT with major radiating elements located on multiple faces of the loudspeaker cabinet shall be oriented so that no point on the DUT is closer than the measurement distance to the microphone, and so that the microphone is as equidistant as possible from all radiating elements.”
This statement is then followed by the following diagram also from the official document.
These are the reasons behind why this particular orientation of the subwoofer was chosen for the measurement session.
In order to be fair it should be noted that Velodyne feels that the performance of their product may have been hampered somewhat by measuring the subwoofer in this orientation. Unfortunately I did not communicate this bit of information to Velodyne prior to the tests and the EQ-Max-15 has since been returned to Velodyne so a further test of it in the down firing orientation for comparison is not possible. Regardless, kudos to Velodyne for having the confidence in their products to submit them to this type of in-depth evaluation in the first place. Having covered that, let’s proceed to the outdoor measurements that were gathered.
Velodyne EQ-Max 15: Effect of Low and High Pass Filter Settings
Above is the effect of various setting of the low pass filter on the EQ-Max 15’s response. These were at the minimum, maximum, 11 o’clock and 1 o’clock positions on the dial. The black trace is with the low pass filter defeated.
Velodyne EQ-Max 15: Effect of EQ Presets on Response
In the chart above is the basic response of the EQ-Max 15 using the various factory EQ settings. The Movie pre-set provides an overall level boost and gooses the 30-50Hz region a bit. The Game setting seems to more aggressively filter the low end and boosts the response into a peak centered at about 63Hz. The Rock setting induces an EQ boost centered just above 50Hz. The flattest response is found using the Jazz / Classical pre-set, so it was used for the rest of the measurements.
Velodyne EQ-Max 15: Basic Frequency Response as Tested
The basic raw response of the EQ-Max 15 as measured outdoors in the Jazz EQ setting and with the low pass filter defeated, falls within a 6dB total window over the frequency range of 29-128Hz. The Velodyne specification is 23-120Hz +/-3dB which matches what was measured reasonably well except for the outdoor measurement indicating less ultimate low frequency extension.
Velodyne EQ Max Internal Auto EQ
I unfortunately did not get a chance to properly evaluate this particular aspect of the EQ-Max 15’s performance. I attempted to run the auto EQ routine in room multiple times with varying placements before packing the unit up for return shipment but did not observe a change in the measured output of the EQ Max-15 before and after running the routine. I attempted restoring the factory settings using the remote control and rebooting the unit. I am not sure if the unit had perhaps a fault somewhere, perhaps a short in the supplied microphone cord or I may have made some sort of error setting up the auto equalization routine myself. Unfortunately we had already arranged for pick-up of the unit so I did not get a chance to investigate further. I apologize to Velodyne and any readers who may have been interested in this particular aspect of the EQ-Max 15.
Velodyne EQ-Max 15: Waterfall Decay
Velodyne EQ-Max 15: Group Delay
The response of the EQ-Max 15 in the time domain shows no area of concern, never breaking 1.5 cycles of delay. There is a slight increase below 35Hz likely due to the vent tuning and rumble filter employed, but is much less dramatic than that seen in some other bass reflex units and should not be of audible consequence.
Velodyne EQ-Max 15: Long Term Output Compression
Above are the results of the output compression test for the EQ-Max 15. It maintains its basic response well up until the nominally 110dB output sweep. At the 115dB level it is obvious that the limiting circuit is intervening heavily and the response shape has changed by a large amount.
Note on Output Compression Testing: This is by far the most demanding measurement type conducted on the subwoofers during our testing and will reveal any issues with overload, port compression, port noise, driver distress, creaks, rattles, buzzes, etc. Additionally this is outdoors with just the subwoofer operating so there are no nearby walls or objects to vibrate and no upper frequency content from other speakers that would normally help to cover up or mask any objectionable noises from the sub in a typical room. Any sort of audible distress or issues with the subwoofer will be readily apparent in this environment.
During the final two sine sweeps of the output compression test the driver in the EQ-Max 15 did seem to be overloaded and out of excursion in the 30Hz range and did develop some doubling and a mechanical suspension noise. There were no notable cabinet resonances or buzzes. I thought I might have detected some port chuffing but if I did it seemed to be of less concern than the driver. If the volume was reduced a little the sub was free of any notable noises. My impression was that the 750 watt rated amplifier is perhaps capable of more than this driver can handle in this application. (Note: Velodyne’s engineers feel that this may have been at least partly attributable to not operating the subwoofer in its normal orientation.)
Velodyne EQ-Max 15: Output Compression Magnitude
Above we have another way of looking at the output compression which shows only the amount of compression of the signal occurring. The EQ-Max 15 performs very well up to and through the 105dB nominal sweep with no appreciable compression shown. At the 110dB level there is some compression starting to occur but it is less than 2dB over most of the range. During the 115dB sweep there is a large amount indicating that the system is clearly at its maximum effective output levels already.
Velodyne EQ-Max 15: Maximum Long Term Output Level
Looking at the maximum long term output achieved by the EQ-Max 15 during output compression testing it falls into the middle range of all commercial subwoofers tested thus far. From 40-80Hz it is quite strong and is in the upper range of units tested. This octave is the meat of the bass range and corresponds well with the subjective impressions during the listening test of the EQ-Max-15 having a lot of capability. Above 90Hz and below 30Hz it is capable of less headroom.
Velodyne EQ-Max 15: Total Harmonic Distortion
Velodyne EQ-Max 15: 115dB Sweep Distortion by Component
Total harmonic distortion and distortion by harmonic component testing reveals that the EQ-Max 15 is very clean down till almost 30Hz even running flat out at its limit, with THD under 5%. Below 30Hz the amount of distortion rapidly increases, which is expected as the cone excursion increases and the frequencies extend below the effective vent tuning. Looking at the harmonic makeup of the distortion reveals that it is primarily composed of the 2nd harmonic followed by the 3rd which is what you would want to see as higher harmonics are often noted as being more offensive to the ear. The notch in THD at about 23Hz followed by an upsurge seems to indicate that this is the system vent tuning.
Velodyne EQ-Max 15: CEA2010 2 Meter Groundplane RMS Results
Velodyne EQ-Max 15: CEA2010 2 Meter Groundplane RMS Comparison
The CEA-2010 test results show that the EQ-Max 15 is amplifier limited from the 31.5Hz band and up and provides low distortion output. Over the 40-80Hz octave it provides over 110dB of peak output which is substantial. Output is still strong at 31.5Hz, but drops off considerably below that point with a passing result of only 84.8dB at 20Hz. However if distortion is ignored the EQ-Max 15 can muster up an additional 10dB of output at 20Hz producing 95.3dB flat out. (Note: Velodyne’s engineers feel that the shift in tuning by operating the subwoofer other than with the ports down firing may have caused an increase in deep bass distortion, which could lower the CEA-2010 passing output below the 31.5Hz band.)
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Recent Forum Posts:
zhimbo, post: 868077
Remember the room rating includes home theater use, so bass <32Hz is important. That's the qualifier - If you don't much care about <32Hz (and not everyone does), the numbers favor the Velodyne.
Exactly. While I would take the SVS over this on because I am more of a home theater guy, I am sure there are lots of people that care more about the mid bass region and the Velodyne beats the SVS there and would most likely preferred for music. Velodyne is also known for giving your lots of features on their subs (like remote controls) and that may appeal to some.
But for the price, there are other ID subs I would take over the Velodyne.
Hopefully the Klipsch SW115 will be better.
its phillip, post: 868081
Guys, his name is Josh
My apologies to Mr. Ricky.
The PB12-NSD does better at those 2 bands so it meets the criteria.
And yes…My mother gave me the name Joshua.