Adding a bass driver below 80hz to a midbass circuit

I thought that BSC was another thing...it was driver amplitude related to radiation, so no one has to look at roll-off but at the entire range and in relation to mid and tweeter. You would want to put an external woofer with its own amplifier and ( electronic, ca va sans dir...)crossover. Adding another driver to the one existing would modify the group impedance thus the need to modify the existing filter ( I'd put a big coil + capacitor...)
 
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The original design without isobaric arrangement

Viawave GRT145
Accuton Cell C90-6-724
2 x Dayton Audio ES180ti-8
Accutons in 8litre, Daytons wd have had 36 l enclosure (ported). Original baffle dimensions were I think 102x23cm with a 2cm round over and slightly curved baffle
Crossover points on accuton and daytons around 370. I had outside help with this crossover design as I just cdnt get hang of xsim
 

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Hmmm... bad driver assortment. Bringing more drivers would add more trouble!
You're overwhelmed by Dayton woofers, eh ?!
For me, rule is to use only one driver for each band- don't like the low power ?! Ehm, errr....
You say about 370 Hz crossover ? The lower you go, ideally you can add more and more drivers since it should
be omnidirectional....so you're right about BSC.
But....I'd trash that project ( You can give me the accutons !!)
the Viawave GRT145 ...hhmmmm...nice 95 dB sensitivity, being it 4 Ω ...
 
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Hmmm... bad driver assortment. Bringing more drivers would add more trouble!
You're overwhelmed by Dayton woofers, eh ?!
For me, rule is to use only one driver for each band- don't like the low power ?! Ehm, errr....
You say about 370 Hz crossover ? The lower you go, ideally you can add more and more drivers since it should
be omnidirectional....so you're right about BSC.
But....I'd trash that project ( You can give me the accutons !!)
the Viawave GRT145 ...hhmmmm...nice 95 dB sensitivity, being it 4 Ω ...
Thanks for your straight talk, I agree - pretty much stuck with these drivers in Bangkok with not much chance of selling for a fair price
 
yes, I've seen your ramblings in multi-way during these years...😆
Chances are: find a small tweeter, accordingly to the small ( I'd say : perfect) diameter of the midrange >>>5 kHz
And use one woofer>>>700-800 Hz
Make the box ( if needed...) for the woofer and arrange the other drivers externally.
Don't make it lean on the floor and put the woofer at mid-height from floor and ceiling.
More? Use rubber bands to isolate the box, more rubber bands to isolate the other drivers from woofer's box.
Use felt in various geometries to soften ( or null...) the emission from the back of the accuton
 
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Is there any particular sound deficiency you would like addressed?

edit: What impedance version of Viawave?
Will look tomorrow but seem to remember 8 ohm. Had the first pair sent to asia.
deficiency - pretty happy with the choice of drivers but if any weak link it'll be the low efficiency of woofer. 84.5db or thereabouts. They are true 8ohm so it cd be possible to parallel 3 with a slightly lossy filter to help.
 
In my sim the response around mid/tw x/o point is yet to be optimized.
Does it feel like there's something lacking in this respect?

Does the tweeter play loud enough in your opinion?
Did you try listening without woofer RLC network?