Funk Audio FW18.0 Measurements and Analysis
The FW18.0 was placed outdoors in a large field with the nearest large objects a minimum of 60ft or greater away from it, with the driver facing towards the microphone. The mono XLR input was used and an ACO Pacific 7012 measurement microphone was placed on the ground at a distance of 2 meters from the nearest enclosure face of the FW18.0 and pointing directly at it. The M3 Amplifier was set to its #1 or “No EQ” preset and the factory gain and DSP setting were left in effect All measurements were taken in this configuration unless otherwise specifically noted. The FW18.0 was tested on both 120 and 240 volts AC for the sake of thoroughness. (There is virtually no performance difference until the amplifier is required to produce maximum power.)For more info on the testing equipment and procedures please see the article here.
Funk Audio FW18.0: Effect of EQ Presets on Response
Above are the frequency response measurements of the Funk Audio FW18.0 in each of its response presets. As can be seen there is a large variation in both shape and level between each setting. The maximum difference in level at 100Hz is 7dB, 6dB at 50Hz and a whopping 13dB at 20Hz. The Flat setting had a bit of a dip in the middle of the response curve but did fit within a 6dB total window from 19.5-266Hz which was a much wider bandwidth than any of the other presets. The overall shape of each curve varied from what was close to a natural sealed system response and roll off (Flat), to a boosted upper bass and gently rolling off bottom end (Rock), to a rising deep bass response curve popularly known as a house curve (HT). Likewise the very deep bass response varied from steeply rolled off to heavily boosted. This just illustrates a few of the many possibilities available inside of the DSP software. I preferred the Flat setting with the least amount of low end boosting and allowing that to be matched to the room and provided by my own equipment.
Funk Audio FW18.0: Basic Frequency Response as Tested
The FW18.0 was tested in the “No EQ” preset which is shown above. This is labeled as the preset with no equalization but there is still some processing going on in the form of high and low pass filters. The high pass is a 6dB/octave Butterworth filter set at 20Hz that results in a roughly 18dB/octave final roll off below 20Hz. The low pass is a 24dB/octave Linkwitz-Riley filter set at 200Hz. The response fits within a 6dB total window from between 36-190Hz and is rolling off below 40Hz. This is typical of a sealed system without any boost equalization applied to the low frequencies.
NOTE: Typically if multiple system responses are available I will select whatever response curve is closest to the native acoustic response of the system when a constant voltage is applied to the driver. The reason being that heavy EQ manipulation often results in the system running into its limits much earlier in whichever frequency range is boosted the most relative to the others. This can result in the output measurements being limited early or the system being heavily overdriven by a relatively narrow frequency band. It is much easier to gauge the systems capabilities over its full intended operational bandwidth when it is operating closer to its native response without heavy signal processing.
Funk Audio FW18.0: Group Delay
Funk Audio FW18.0: Water Fall Decay
Group delay measurements for the FW18.0 showed no excess energy at any frequency and nothing that could be considered of note. Even with some of the more heavily equalized presets the group delay never got close to even 1 cycle of delay. Likewise the waterfall decay measurements show a quick and rapid loss of 25 to 30dB of energy by 100ms out which is what I typically look for.
Funk Audio FW18.0: Long Term Power Compression
The long term output compression tests for the FW18.0 show excellent tracking of the signal increases through the [email protected] sweep level and on up to the [email protected] sweep. Increasing the level even further to a ridiculous point that would have produced [email protected] finally got the FW18.0 to run out of headroom and start limiting the output. The driver seemed to be running out of clean excursion judging by the distortion and overtones it developed in the deep bass at this level and the amplifier clearly was out of current and was limiting the output. This can be seen in the dropouts in response in the 124dB measurement. The FW18.0 reached 120dB from 40-55Hz during this which is very loud. Despite being driven this hard the system was composed and other than some audible distortion in the deepest bass and some pumping of the output it was free from any nasty rattles, clanks, or cabinet rattles. In fact the cabinet was stoic in its inertness during all of this. The protections and overload behavior of the FW18.0 active subwoofer are effective at preventing the sub from doing damage to itself or sounding truly distressed. The results above are with the M3 amplifier connected to a 240v line. Below is a comparison of how the M3 performed connected to a 120v line instead of the 240v line. There was no difference until driven beyond a 120dB sweep level near maximum output of the system. At maximum output the 120v line started limiting and running out of current reserves just a bit sooner. Unless you are running the FW18.0 cranked for all it is worth for long periods of time you would be very hard pressed to ever notice the difference.
Funk Audio FW18.0: Long Term Output Sweeps 120v AC versus 240v AC Line
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 the test is conducted outdoors with just the subwoofer operating so there will be no nearby walls or objects to vibrate and no upper frequency content from other speakers in operation. These would normally help to cover up or mask any objectionable noises from the subwoofer in a typical room. Any sort of audible distress or issues with the subwoofer are readily apparent in this environment.
Funk Audio FW18.0: Output Compression Magnitude
Looking at only the amount of compression occurring in the output of the FW18.0 it can be seen that there is basically no compression at all through the 115dB sweep where it is less than 1dB! Even with the 120dB sweep it still exhibits very little compression of the output with less than 2dB in the upper bass except for a slight blip at 100Hz which is due to the amplifier limiting the output. This drive level is right at the edge of the output limits for the platform as a further increase results in very little extra output and tons of compression across the entire bandwidth. Considering the output levels being produced in the upper bass and the amount of current being delivered into the drivers voice coil this is an impressive showing.
Funk Audio FW18.0: Total Harmonic Distortion
Funk Audio FW18.0: Distortion by Component
The distortion results for the FW18.0 are also very good. THD is kept well below 10% from 10-125Hz during the 115dB nominal sweep level. Even at the 120dB nominal sweep level it stays under 15% below 25Hz. Driving the FW18.0 hard into the limiter causes the THD to jump up considerably but it still never breaks 10% above 30Hz. A large part of the distortion increase may be due to the amplifier itself as well because the subwoofer is not producing much more actual output at this increased drive level. (Low order deep bass distortion is very difficult to hear and doesn’t get objectionable until truly nasty amounts are produced. Typically other mechanical noises from the subwoofer are more objectionable to the ear and more likely to signal that the system is “out of rope” so to speak.) Looking at the component makeup of the distortion produced at the loudest output levels shows that it is primarily composed of the 3rd harmonic in the deep bass below 30Hz which is typical with large driver excursions. Above 30Hz the 2nd harmonic dominates which is the least audibly offensive harmonic. This corroborates well with my subjective impressions of the FW18.0 sounding very clean with music even while producing chest pounding bass. The 4th harmonic is well down in level and barely reaches 2% above 25Hz.
Funk Audio FW18.0: CEA2010 2 Meter Groundplane RMS Results
The CEA2010 maximum distortion limited short term output results for the FW18.0 once again show it to be a very capable subwoofer. At 31.5Hz the FW18.0 is capable of just about 115dB of output. At 40Hz and above the potential short term output is in excess of 120dB which puts it in the top echelon of subs I have reviewed as far as output capabilities over this range. At the 40 and 50Hz bands it has the highest output I have recorded from a commercial subwoofer. In the deeper bass the FW18.0 also does well recording over 103dB at 20Hz and over 99dB at 16Hz.It even manages to produce passing results at the 10 and 12.5Hz bands which most subs cannot do. The output at the 25Hz band and below is limited by the distortion rather than the amplifier power and likely is a result of the driver running out of linear displacement. If distortion is ignored completely the FW18.0 can produce short term output levels about 1.5dB higher in the deep bass. With a sealed system all of the output comes from the driver displacement and it requires lots of power and lots of stroke from the driver to produce large SPL at low frequencies. The FW18.0 TSADv1 driver was producing excursions of 2” peak to peak or more during the deep bass tests. The CEA-2010 results presented here were captured with the M3 amplifier connected to a 240v line. For comparison’s sake the FW18.0 was also tested connected to a 120v ac line and the result was very little difference. When connected to the 240v line the FW18.0 produced an average of 0.5dB higher CEA-2010 output versus when connected to the 120v line. The maximum increase seen at any particular band was only 0.9dB. Again this shows that the FW18.0 will operate just fine on a 120v AC and there is no reason to feel obligated to use 240v AC for this subwoofer. While it does perform ever so slightly better on 240 volts a difference of less than 1dB at the very edge of performance is negligible in the scheme of things.
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Recent Forum Posts:
Steve81, post: 986362They actually look pretty nice, not quite as nice as the curved cabinet, but pretty sexy nonetheless. Here are some pictures.
FYI, looks like Funk is offering a lower cost variant of the 18.0 in a simpler 20“ x20” x 20" cabinet with rounded corners. Price is $2,550, which is a pretty substantial discount.