Systems List › DIY › Mach 5 Audio UXL-18 Sealed
Testing the sealed system containing the Mach 5 UXL-18 driver reveals that the response shape is well extended with only a modest hump centered at 55Hz and useable response up to a little past 200Hz if needed. Very long throw drivers such as this rarely have a flat response shape due to inductance. The behavior of the UXL-18 shows that some effort was given to addressing this issue in its design.
Looking at the sensitivity measurements this system puts up a remarkably good showing for a driver of this type indicating that the motor is strong with a sensitivity of roughly 91dB. The response decays very rapidly with no notable energy storage issues. The performance during the long term output compression testing is very good showing just 1dB of compression during the 115dB nominal sweep level.
During the 120dB nominal sweep the results was no more than 2dB of compression mostly above 60Hz. At this point testing was stopped due to the onset of serious compression and due to the fact that the driver was starting to exhibit some mechanical noise from the huge excursions produced in the deep bass.
Unfortunately distortion testing was not conducted as the driver was damaged due to an incorrectly set gain in the signal chain. We hope to eventually get this data collected. However there is some distortion information gathered from the CEA-2010 short term burst testing. THD seems to be dominated by the 3rd harmonic and overall distortion seems to be low as the output levels recorded with passing distortion are impressive for a single sealed 18 producing greater than 120dB above 40Hz and strong deep bass output before hitting the distortion limits. 108db was achieved at 20Hz. The system was not pushed any further in the deep bass since the driver was starting to produce very large excursions and some mechanical distress noise.