Need Help: Practical Difference in Subwoofer F3

[tommarra]

I have a choice to build two subwoofers either with or without a passive radiator.
With the Passive Radiator the F3 is ~ 27.5 Hz, F6 ~ 23.05, F10 ~19.5

Without the Passive Radiator in a sealed box the F3 ~ 33, F6~ 26, F10 ~ 21.28

(Also see the attached graph...the pink line is with the PR and the Yellow is Sealed)




The sub will primarily be used for HT and compliment a pair of Finalists.

My questions is that in real world situations are the two variations really different? In real terms is the difference in the modeled response enough to warrant additional $250 in passive radiators?


Few more details on the parts used

Cabinet is 34.5 liter

Subwoofer amp is Keiga KG5230 which has a HPF at 15Hz and a bassboost 4dB @ 25

Subwoofer is SB Acoustics SB29SWNRX-S75 10" Subwoofer from Madisound

PR is SB Acoustics SB29NRX-00 10" Passive Radiator from Madisound.

Will greatly appreciate word of advice on real world difference on the modeled differences.


My living room is not too large with dimensions are approx 12 x 20 x 12.

Thanks in advance,

Nishant

[taloyd]

I'd firstly recommend a much bigger passive radiator - you want much more displacement available from the passive as the active - that's why many designs either use a 12" PR with a 10" (Klipsch, etc.) or two passive radiators - the latter has the advantage of a bit of force cancellation, if implemented appropriately.

Secondly, I imagine the PR design would be superior since distortion is proportional to excursion - and a PR (exactly like a ported) vastly reduces excursion demands. The minor penalty in group delay, etc. is negligible.

Just my $0.02.

cheers,
-Tal