Systems List › DIY › Sound Solutions Audio Xcon 18D2 Sealed
Sensitivity for this system is middle of the road reaching a little over 92dB near 45-55Hz which is good but rapidly decreasing outside of that range and falling to about 86dB near 100Hz. The basic frequency response is peaked near 50Hz and is about 17dB down at 20Hz, 7dB down by 100hz and about 10dB down by 200Hz.
The response decay in the time domain is well behaved as is usual for sealed systems and indicates just a little bit of delay near 40Hz but it is not nearly enough to be consequential or audible. The long term output compression tests of this system show decent performance with just about 2dB of signal compression during the nominally 115dB output sweep. By the 120dB output sweep compression has grown to about 4dB at 50Hz. Finally during the 122dB nominal sweep this has ballooned to about 5dB of compression at 50Hz and the driver was starting to make mechanical excursion noises so the testing was stopped there. Note that there is also a significant amount of shifting of the response shape going on as the level is increased.
The output is actually expanding at 35Hz while it is compressing near 50Hz and the response peak is moving lower in frequency. Looking at the distortion results from the levels used during the output compression tests it can be seen that the distortion is low during the 105 and 110dB sweeps. THD remains at or below 10% above 23Hz during the 115dB sweep but deep bas distortion has increased.
During the 120 and 122dB sweeps the Xcon driver was clearly driven outside of its comfort zone in the deep bass region where very long excursions were produced. Above 25HZ the distortion levels are still reasonable for the input power applied and sound output.
Of note is that the harmonic make-up of this systems distortion is dominated by the 2nd harmonic which is the least offensive harmonic perceptually. The distortion limited burst output results indicate that the system has generous headroom at 40Hz and above. The deep bass output is a little lower than expected because while the driver had plenty of excursion left as evidenced by the results produced with no concern for distortion, the 3rd harmonic limited 20Hz and lower results. If distortion is ignored much higher levels could be reached. The high levels of the 2nd harmonic also showed up in the CEA-2010 tests.