Systems ListFunk AudioFW21.0

Measurement Details

AmplifierClosed Loop
Outside Temperature76 F
Date TestedApr 18, 2016
Settings & EqualizationNone...

Notes

Measurements of the FW21.0 reveal a powerful and competently engineered system. The base frequency response with the DSP set to the raw un-equalized response shows that the response shape exhibits a rising top end that plateauís from 100 to 200Hz where a low pass filter is engaged with a 24dB octave slope. There is a very minor resonance of some kind at 192Hz but clearly this system could be to cover frequencies up to about 200-250Hz if needed. The overall raw response fits within a 6dB window from 58-235Hz and indicates a very high efficiency driver in a small sealed cabinet as expected. Note that this is the un-equalized response shape only and that the onboard ALL-DSP allows a number of preset curves or custom signal shaping that can be used to change the response shape to whatever is desired for the end user/room. (Since this takes a large amount of time to measure and tweak and it was already checked in the previous FW18.0 review, it was decided to forego another set of measurements with the FW21.0. Please check the ALL-DSP measurements for the FW18.0 and/or the ALL-DSP website for more information on it. ) Virtually all closed loop systems employ baked in equalization these days. With sealed systems it is generally used to extend the deep bass response and flatten the response shape. However it cannot change the output limitations of the system so they will only be effective until the amplifier or driver limits are reached. Also of note is that the M1 amplifier does not have clear roll off in evidence until about 8Hz on the low end. This will allow the FW21.0 to take advantage of room gain until very deep frequencies.

The measurements of the time domain response of the FW21.0 show nothing of consequence other than a well damped small sealed system. Group delay never approaches even 1 cycle and the waterfall and spectrogram plots show no ringing to be concerned with.

The long term output compression testing for the FW21.0 starts at the usual level corresponding to an output of about 90dB at 50Hz at 2 meters ground-plane. The FW21.0 exhibits excellent behavior through the next 25dB increase in the signal strength with compression of the output by only 1dB or less during the 115dB sweep. Increasing the demands another 5dB for the 120dB sweep caused the FW21.0 to start to sound just a little pushed in the deepest bass during the sweep due to high excursion from the driver and increased harmonic distortion. Compression of the output is still commendably low at only 1 to 2dB. An increase of 3dB for the next sweep caused the amplifiers to mute accompanied by a loud click from the driver at the start of the sweep. This is not the driver mechanically but rather a turn off noise from the amp. Reducing the volume slightly to what would be 32dB of gain from the 90dB base measurement allowed the FW21.0 to complete the sweep without the amplifiers disengaging, though there does appear to be a bit of current limiting during the 122dB measurement near 20Hz and at 120Hz. By this point the driver was grumbling due to the extreme amount of excursion anyway and the FW21.0 was compressing the output by about 2 to 3dB in the deep bass. During the loudest sweep the FW21.0 produced over 107dB at 20Hz, nearly 120dB at 40Hz and a very loud 125dB or more above 64Hz. A repeat measurement at the 90dB level showed some thermal buildup and effects on the driver with compression of about 1 to 1.5dB away from the system resonance. Considering the amount of power dumped into the driver this is not a bad result. The FW21.0 did exhibit some distorted sounds from the driver in the deep bass if driven to its limit but otherwise was free from any resonances, hardware or cabinet noises. The amplifiers would kick off if asked for too much current but this occurred a bit before the driver could really get into trouble so it seems that the amplifier and driver match is a good one which allows as much headroom as possible but wonít let the driver get bottomed out.

The distortion results for the FW21.0 are likewise quite good and well controlled. The 110dB measurement shows THD at 1% or less above 45Hz with a smooth rise down to about 5% at 20Hz at 10% down near 10Hz. The 115dB measurement shows THD to be 5% or less above 34Hz, 11% at 20Hz and about 15% down near 10Hz. Increase the demands on the system another 5dB for the 120dB sweep increases the THD notably and indicates that the driver is starting to near its linear excursion limits in the deep bass. THD stays at 10% or less above 38Hz, rises to 38% at 20Hz and stays in the range of 40-45% over the 10-20Hz octave. The final 122dB sweep pushes the driver even harder. THD is at 10% or less above 45Hz but reaches 60% or greater below 20Hz with a peak of 78% at 14.5Hz, indicating that the driver is clearly a bit past its comfortable operational envelope. Note that this measurement indicated that there was some limiting or protection action taking place in the amplifier near 25Hz and above 120Hz.

CEA-2010 results for the FW21.0 indicate an especially strong performer for a system of this size. At 10Hz the FW21.0 system recorded a solid reading of 94.4dB. Very few systems can produce anything noteworthy in this bandwidth so this is a strong statement to the drivers low distortion and displacement capabilities. Output rises smoothly from there as expected from a sealed system recording about 107dB at 20Hz, reaching over 120dB at 40Hz, 128dB at 80Hz and a very loud 130dB at 100-125Hz. If distortion was ignored the FW21.0 would produce about 2dB more output when pushed all out at the 10-25Hz bandwidths. The amplifiers would mute the outputs if pushed any harder in these low frequency bandwidths. The distortion limited burst results were also captured in the HT room at the head rest of the main listening position. With the reinforcement provided by the room the FW21.0 was capable of producing short term outputs of 109-110dB at the listening position over the 10-20Hz octave. 

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