Subwoofer boxes / cases - quick question

**Pabs** · 11-26-2004, 06:54 PM

Hey all

Install coming along nicely, hence why i havent posted on here recently (been very busy)

Time has come for me to design my boot install.

a question i have tho, is that I have seen a lot of people with their subwoofers out of a box, and in reverse position to normal (cone facing side, with magnet out of the box)

Can this be done with ANY subs? Or only free-air subwoofers. I think thats what a free-air sub is, isnt it?

I own two 10" 350W max (110W RMS) RM audio subwoofers, and just want to save space. ATM i have a box for both, but i end up with no boot left.

Cheers all

**LeoTheHamster** · 11-27-2004, 04:00 AM

You can mount any sub arse-out

**frodobaggins** · 11-27-2004, 06:48 AM

They have boxes, just the subs are backwards.

**dbxxx** · 11-30-2004, 09:28 PM

be sure to check the polarity of your wiring and/or change the phase on your headunit if you plan on using more than one sub.

**Draxin** · 12-02-2004, 09:38 AM

maybe a stupid question (sorry im new to car audio) but what is the point of inverting the sub??

**RedGTiVR6** · 12-02-2004, 10:17 AM

it's for looks, there is also some talk that it will help keep the sub a bit cooler...come protection could also be considered a plus....but that might be digging for reasons...

theoretically your box can be a bit smaller since you don't have to account for the sub it self taking up air space.....but that's stretching it as well....

some subs are absolutely georgeous on the back side (Focals for instance) and to show off the back side of the sub is to make a statement....

you can do it with MOST subs, but not all....some are harder than others

if you want to save space go with a sealed box, you will sacrifice some bump though.

just try not to skimp on the air space too much, you can cause some problems

good luck and post pics when you are done!

**mgithens** · 12-02-2004, 12:32 PM

ahh, but the sealed box has the overall better sound, he has a hatchback, so he'll already have great cabin gain... just build a sub box per the manufacturer recommendation and be done with it... I have a single 10" in a Scion xB and I hit just under 120db.. PLENTY!! I power it with 50x2 MTX bridged to mono for 200x1...

some basic rules of thumb... 10db is twice as loud (it's a log base 10 scale)... 3db works out to be about twice wattage... also 3db is about the average gain on a ported enclosure... but that 3db comes at a price, you will not have as flat a sound curve, it will peak where the port is tuned - and you will trade off lower end performance...

also, a "free air" sub is to be used in situations where a box will not be available, so as the woofer goes in and out it will not rely on the box for "resistance"... you always have to separate the front air from the back air, so a typical free air could be mounted in a vehicle and use the entire trunk space... there really isn't a way to use a free air in a hatchback...

**RedGTiVR6** · 12-02-2004, 01:20 PM

funny, I thought 3 db was twice as loud....

or at least that was the accepted rule of thumb in SPL comps.....

but it has been a few years since I was in that game.

sealed will sound better, ported will be louder. It's all up to what you want, louder or better quality? To the average listener you won't notice a difference, if you demand a bit more from your system and have trained your ear to noticed differences, deffinately go with a sealed box.

either way, you are started off in the right direction, that's a good thing, and you are wanting to do this to your ride...that's another bonus IMO....

=]

**mgithens** · 12-02-2004, 03:24 PM

Originally Posted by Red GTi VR6

funny, I thought 3 db was twice as loud....

or at least that was the accepted rule of thumb in SPL comps.....

read the 4th paragraph here

twice the power, means twice the wattage... twice the volume is 10db...

I'm positive on the "twice as loud thing"... hearing damage begins at around 85db depending on length of exposure... so anything above 115db is just silly...

"For unprotected ears, the allowed exposure time decreases by ONE HALF FOR EACH 5 dB INCREASE in the average noise level." from here