Faital 18XL1500 + port length

Hi there!

Got an option to pick up a pair of Faital 18XL1500 cheaply with the goal of building a compact, single driver, reflex sub for PA use.
In that regard I got two question that I hope you could help me with :)

1) With a volume of 285L and a tune of 30hz i get a F3 of 28 which is plenty low for what I need.
However, modelled cone excursion at 1kw exceeds xmax with 1.5mm at 40hz. Is that amount critical to the longevity?
Going smaller in enclosure volume or increasing the tune gets me below xmax but makes the port length too long to build.
Is there a way around this?

2) My plan was to build a onken style enclosure with a total of 6 tall aspect slot ports along the sides. The baffle will be recessed for stiffness and protection of the driver, creating a sort of 'enclosure within a shell' (I have made a crude sketch of the design below from a top down view)
Where should I measure the ports from?
And is there a critical dimension at the corner that I need to be aware of?

I hope all that makes sense.
Cheers.
 

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GM

Member
Joined 2003
Greets!

With a 3 kW transient power rating, 28 mm Xmech/damage, then only going over a 12.9 mm Xmax by 1.5 mm shouldn't pose any problems long term unless repeated long pipe organ, synth, etc., 'sustains' are going to be a significant part of the program.

Hmm, assuming the extended front sides go full perimeter to create a crude low pass filter, making the cab technically a BP6, then seems to me that the vents are being 'driven' by both sides of the driver and can't be simmed as a simple BR and not up-to-date on any of Hornresp's (HR) latest multiple pipe alignments ('ROAR'?) to know which might apply, so hopefully others will chime in.

WRT the pipe end correction at each end being different with the rear needing to be calculated based on this attached axial length bend calculation (71.4 cm) and the front just the initial segment.
 

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