Rockville 18'' Box Build 30hz?

carlk5555

Member
2016-02-25 11:24 pm
I plan on buying 2 Rockville RVW1800P4 18 inch subs and would like to tune to 30hz. I plan to put them in seperate boxes and they are going to be used in my house so i dont care if the boxes are big. Ive never built a box before so im new to all this. I listen to rap and hip-hop mostly. Would it be good to tune to 30hz? I want to be able to hit really low notes well. Could anyone help me out with a box design that will get the most out of these. I know they're cheap but im on a budget and its just for me not for shows or anything.
Thanks.
 
I am a fan of finding deals and using lesser named stuff, but if the mfr doesn't even post T/S specs online, I would look elsewhere personally. That is not to say if you get them and build a box they won't make noise. I would take a look at these: Dayton Audio DCS450-4 18" Classic Subwoofer 4 Ohm or even jus the 15 to save dough... The site even gives you ideal parameters for the build.
 

Jensen567

Member
2016-02-13 9:33 pm
If you only want to get down to 30Hz I have a pair of Polk 12" DB1240 SVC drivers I would sell you for less than the price of a single one of those Daytons.

If my calculations are correct they should be able to hit a -3dB of around 26 Hz in a ported box of about 3.4 ft3, which is quite a reasonable size for 26Hz.

T/S are in the datasheet if anyone wants to double check me on that. I know they are car woofers but they are actually quite suitable for hifi use.

http://www.polkaudio.com/Media/POLK/Product Manuals/dbSub_MN.pdf
 
Thanks, though 8 ohm, which theoretically will be close: Amazon.com : Rockville RVW1800P8 1800w 18" Raw DJ Subwoofer 8 Ohm Sub Woofer 240OZ Magnet : Electronics

The posted specs are a bit bogus since BL, Mmd are way off relative to the T/S specs, but the only difference is vent length and of course two different tunings, though ideally this would be empirically determined to best blend in room.

They claim a high Xmax, but its accordion surround pretty much limits it to ~5 mm, so 80-100 W usable power handling below ~70 Hz, though this is still ~115 dB/m/2 pi space in ~14 ft^3 tuned in the ~22-27 Hz range with a 10" dia. tube ~13 - 23" long depending on which of the 8 ohm driver's specs are most accurate.

If the drivers have a higher Qts, then worst case is you have to either damp the vent or seal it up completely.

GM
 
Hi All,

;):D :2c: of :eek: Estimated Parameters that is at least Consistency checked :cool:

b :)
 

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Greets!

Hmm, the only specs I've seen are for the 8 ohm listed on the posted Amazon site, which equate to 0.47 using T/S and 0.45 using Cms, BL; with Fs shifting from the published 25.02 Hz to 30.87 Hz using HR.

As you know, 4 ohm drivers typically have nearly identical T/S specs to their 8 ohm models, so very curious how you arrived at a 0.2 Qts.

GM