two7’s vs one 8

tajanes

I’m considering trying another bi-amped (active / passive combo) 3way; sticking with a Beyma 5in coax (probably vented) and looking at possibly two 7in Wavecor SW182BD04s or a single 8in DA RSS210-4, sealed for the lower end. Net box volume of either set-up look to be ~similar. My current 3ways were set up with a 10in passive radiator which creates quite the low end, but I’d like to try a sealed bass with its gentler roll-off, by focusing on where the in-room -6dB falls, more so than the cliff falloff of either a ported or PR @ -3db.

The DA 8in has an Sd of 213.8cm3 vs. the Wavecor at 131cm3 each. So, on this metric (alone) ++ to the Wavecor (i.e. per the same amount of air being pushed the twin Wavecors will be moving less, with anticipated less distortion). Yet the DA has an Xmax of 11mm vs. the Wavecor’s 7mm, so the DA looks to be able to ultimately move more air (and could play louder / eq’d with less issue of bottoming out).

Thoughts?

tktran

VituixCAD2 to the rescue!

As expected, in the sub bass you're displacement limited, because Vd matters for than Power.
213.8 x 11 > 131 x 2 x 7.

So under 50Hz the RSS210HO-4 will give a few dB more output, where as in the mid-bass ~100Hz and up, the twin SW182BD04 will have a slight advantage.

Also (but not shown) is that the twin 7" have a voltage sensitivity advantage of some 5dB @100Hz. That's not something to be sneezed at.

I'd choose the twin 7...

tajanes

Thx for your work, and input on this

Ed_Perkins

Are you talking about the RSS210HO or the RSS210HF?

tajanes

the HO