Sundown X/M 15 vs U 18 in ~4.5 cubes @ 32 hz w/2800 wRMS

[Revdoc]

Looking for opinions on a 15" mega platform (X or M series) Sundown sub vs. an 18" "normal" sub like the U series. I have about 4.5 cubic feet net to work with, about 64 square inches of port area, and 2800 watts RMS. I would love to run a mega platform 18", but they require about 7 cubes and 100+ inches of port area. Is the extra excursion of the mega 15" enough to make up for the cone area disadvantage vs. an 18"?

 

Modeling them in WinISD, the mega 15" is louder from 29 hz to 36 hz, and the 18" is louder everywhere else. I know that's not always accurate in real life. Does anyone have experience going from a larger sub to a smaller sub with more throw and finding the smaller sub is actually louder?

 

Also open to suggestions on another 15" or 18" sub that would work better with this particular box/port/power setup. I have had several Sundown subs in the past and liked them, but I'm not dead-set on them.

Edited February 26 by Revdoc

[Joe X]

In your situation I would go for 2 12s, say the sundown M12s, total cone area is near a 18 and 4.5 cubes net and 70-80 square inches of port area will be enough for them. You can then upgrade the power later if you want and go louder than the single 18 would be able to.

 

Wanting to have a 15 to sound as loud as a 18 on the same power is rather difficult, you usually need like twice the power on the 15 to reach the output of the 18 and then it can be done but it is more expensive, you need a better electrical, amp and sub.

[Revdoc]

That's a good idea. I done tons of dual 12 ported systems, so I've been changing it up with the 18 recently. Last setup was an old Obsidian Audio 18 in the same 4.5 cubes, a little less port area and only 1200 watts. It worked really well, even though the box and port were on the small side.

 

But, with 2 M12s I could use twice the power and make up for the small surface area loss vs. an 18. It will just be way more expensive lol. 

[Joe X]

Actually 2 12s will give similar output as a single 18 on the same power, if you gave twice the power you would get louder than a single 18 and you can go higher than twice the power, likely 5-6 K is possible.

 

A single 15 you can do but due to the significant difference in cone area you would need a lot of power to reach a 18, it would be very expensive not for the amp, amp is cheap but for the electrical, the 15 would likely really need twice the power to rival a 18, about 3dB is what a 18 has on a 15.

 

If you still want a 15 check out steve's videos on the new deaf bonce 15s, looks like those subs are highly efficient due to the gigantic motors, no t/s params for them yet but for sure will be one of the loudest 15s ever out there.

 

Edited March 1 by Joe X