Double 18 with Precision Device PD186 build

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What is the best tuning frequency for this box/driver compliance

Well, the pioneers of audio [electrical & mechanical engineers with a few physicists rounding them out] claimed that the ideal ratio of air mass to driver suspension compliance ratio for a bass reflex [vented] was 1.44 and when tuned to Fs had the optimum transient response, i.e. ~136.28 L tuned to Fs based on published specs, whereas a T/S max flat alignment is ~453.55 L tuned to ~27.7 Hz, though due to differences in the various program’s math the latter can be a bit different, but not audibly so.

Anyway, here’s a quick comparison sim of the two and any alignment between these two are considered acceptable [and common] depending on what performance trade-offs you choose. As you can see, it’s about trading peak power SPL for a lower tuning and inaudibly smoother transient response [HR files attached].

Decided to do a TH to compare to the ‘classic’ BR even though it’s probably too large [HR file attached]. Note that since the TH doesn’t have much of a ‘tail’ below the line, its transient response is the best of the bunch. Note too that all sims have no damping to speak of, so all the little squiggles and high Q peaks are normally absent or at least extremely muted.

GM
 

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Decided to do a TH to compare to the ‘classic’ BR even though it’s probably too large [HR file attached]. Note that since the TH doesn’t have much of a ‘tail’ below the line, its transient response is the best of the bunch. Note too that all sims have no damping to speak of, so all the little squiggles and high Q peaks are normally absent or at least extremely muted.
Hi GM,

Did you consider the low BL^2/Re ratio for the PD.186 for TH use?

Cheers,
Djim
 
Well
Over 2300lbs of bb cut today
Also received 64 handles...48 casters and speakon plates
 

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Hi,
Can you refer to the right specs link? Note: they don't model/fit for the same enclosures.
Old/previous Precision Devices PD.186 and new PD.186/2
PRECISION DEVICES PD 186, 8 Ohms Fs 27.00Hz VAS 353.00L Qts 0.313, Xmax± 9.0mm, Sens.96.9 dB/2.83V/m
PRECISION DEVICES PD.186/2, 8 Ohms Fs 34.18Hz VAS 192.15L Qts 0.523, Xmax± 10.5mm, Sens.94.6 dB/2.83V/m
link PD.186/2
:scratch2:
 
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