Silver MemberUsername: Lord_huggington
Post Number: 404
I also tried 2 Eclipse SW8200's sealed in 1.25 NET each, 375W each, QTC 1.2 / FC 44 Hz, and the lows were so fking nuts, it was like 20-30 Hz was louder than 30-40 Hz. It wasn't head-smacking loud like the XXX around 36-42 Hz, but they held their own.
Where did I go wrong with both boxes? I have the XXX and I don't know what to do with it, I was going to re-cone it to an 18" for 9 NET @ 32.8 Hz, foreward-fire and sealed off. AQ 1200 or 2200 with a battery for power, stock alt cuz I'm mad broke .
I can fit 2 15's ported / foreward fire with port in the middle (~4.3 NET each @ 34.9 Hz with 14.5" of port per cube, port ratio 1:3), or I can do 2 18's sealed in 5.25 NET each & foreward fire. Each setup would be sealed off from the trunk. Keeping an ability to upgrade, I'd like to do either of these, with the most popular cut-outs being (outside) 15.625" with a (inside) 14.125" cut-out, 18's that are (outside) 18.5" and (inside) 16.75".
LMS motors - they have low sensitivity, but do they make up for it in actual out put?
Does Sd * Xmax on paper calculate into a real-world result?
For instance - not that I can afford these - but I probably one day will ;) - 2 LMS Ultra 18's sealed in 10.5 NET and 2 SS XXX 15's in 8.75 NET @ 35 Hz - the 18's have Sd (1200) * Xmax (38mm) * 2 subs = 91200, the 15's have Sd (756.77268) * Xmax (39.88mm) * 2 subs = 60360. Say both are powered by a Soundigital 16k.
The 18's move 1/3rd more air, and in 5.25 NET sealed it yields about QTC .5 / FC @ 30-32 Hz, probably the best response ever.
Sensitivity on LMSU - 89.7 dB (+3 dB for 2 subs) = 92.7 dB
Sensitivity on XXX - 90.8 dB (+3 dB for 2 subs) = 93.8 dB.
The XXX's being ported, there's a +3 dB gain at 35 Hz = 93.8 + 3 - 92.7 dB = theorhetical 4.1 dB gain over 2 sealed 18's.
I'd like to know if they'd equal out - is 4.1 dB @ 35 Hz equal to +30000 square centimeters of cone area with a sealed box? That's equal to something like 3 10's that each have a 30mm Xmax. The pair of 18's would be moving about as much air as 9 10's that each have a 30mm Xmax, quite shocking.