18sound 21LW1400

[exurbia]

Has anyone out there tried these in an OB ?
I have just bought 4 of these 21" ELF drivers, i wanted the 24" precision Devices monsters.
Freight costs to Oz killed that idea.
So, i got the next best thing. The maker suggests that they are suitable for horn loading or reflex boxes, reflex boxes give me 265 Litres per driver tuned at 27Hz. A bit large, the other half will definately take issue with this size box.
Bifurcated horns with two drivers in each are just overkill and totally silly, also domestically disastrous.
They will be going into a very large room in Perth WA, in case anyone wants to have a listen.

[exurbia]

My son has suggested loading them in an Isobaric box, half the size twice the grunt (almost).
Tuning becomes a problem with this small a box as port sizes become an issue.
New question, would Isobaric loading work with an Onken type of box. Does the cabinet tuning remain the same ? allowing for the extra volume of the clamshell for the isobaric loading.

[GM]

Tuned low, this driver wants a TQWT (reverse tapered pipe), so at a glance ~200 L net for a single or ~100 L net for two driver isobaric to get down to <20 Hz.

Since the Onken is a BR, it's suitable for isobaric if the driver's summed specs meet its rather narrow criteria, though as a general rule it's not going to be suitable per se, i.e. meeting the ~35 cm max vent length at a minimum 0.75*Sd vent area due to the low effective Vas.

GM