Two passive radiators with different tuning frequencies

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Can anyone provide insight into what the tradeoffs would be if I were to design a subwoofer with a pair of passive radiators that are tuned to somewhat different frequencies?

Imagine I have a given design with a single driver, amp, and two passive radiators in a specific box, and the output rolls off just a bit too soon for my tastes. Would there be any sense in adding a bit more mass to one PR in the hopes of getting a little more low frequency extension? My gut tells me it could work, but because there's no free lunch, it would also shift the rolloff frequency upwards. Qualitatively, it could come across as having a slightly less steep rolloff. Is this a common approach or is it a dead end?

Is there any way to model this? I use WinISD, but I also recently purchased BassBox 6 Pro.
 
Don't know how to model different passive radiators that are tuned to somewhat different frequencies, but what Brian Steele wrote in replies #12 & 14 makes sense.
Using two PRs in same system, tuned to different frequencies?

On 10/15/18, in post #15, Silent Screamer wrote:
"Let you know when I build my new sub. I can easily adjust both PR individually to find out."

Don't recall him posting any results after that.
 
Thanks. Any recommendations on the best tool to model things like this?

I used WinISD to generate SPL of two differently-tuned PR each in their own box, and then manually added the levels logarithmically, and the results sure didn't seem very interesting. Still, it would be nice to get those results automatically.
 
Would it be so different from having 2 sets of speakers using the same drivers but one sealed and the other ported?
As GM said in a post many years ago they load the room in different ways why would having dual but different passive radiators be different?

Yes, because the PRs are in the same cab, so will sum to a single tuning; now if it was two differently tuned vented/PR cab alignments it would be a similar situation and using different tunings in a stereo/HT app to best overall blend with each speaker's local room acoustics is something me and a very few others have recommended when appropriate.

GM
 
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