Quick Question About Downfiring Boxes...

[RAM_Designs 5,000+ posts]

I'm being asked to make a downfiring box for a friend of mine who doesn't want his subs exposed to all of the cargo he carries around. He just wants a simple sealed box for a pair of Polk momo 8's.

The question that I have is, how much room do I need to give between the sub and the floor of the vehicle? Or in other words, how long do I need to make the "feet" that attach to the bottom of the box? I've never built one before, and was just curious before I started planning. Anyone out there built one before?

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[XanderMoser 10+ year member]

I'm being asked to make a downfiring box for a friend of mine who doesn't want his subs exposed to all of the cargo he carries around. He just wants a simple sealed box for a pair of Polk momo 8's.
The question that I have is, how much room do I need to give between the sub and the floor of the vehicle? Or in other words, how long do I need to make the "feet" that attach to the bottom of the box? I've never built one before, and was just curious before I started planning. Anyone out there built one before?

Just give it xmax + 1 or 2"

 

[hoxie08 5,000+ posts]

Just give it xmax + 1 or 2"

agreed.

 

[mlstrass 5,000+ posts]

I've built several HT subs that are downfiring, and usually do 3 1/2"- 5" of clearance, but those had a downfiring port. Honestly 2"-3" should be all you need for sealed.

 

[JohnBlayz142 10+ year member]

2-3" total

 

[RAM_Designs 5,000+ posts]

thanks everyone.

 

[Twistid 5,000+ posts]

i read on the forum that downfiring makes the suspension sag eventually...

im probably wrong, just regurgitating what i've read

 

[dvrmstrng 5,000+ posts]

my buddy has 2 memphis 8's downfired and they probably have less than 1"

 

[Doodaddy 10+ year member]

i read on the forum that downfiring makes the suspension sag eventually...
im probably wrong, just regurgitating what i've read

That would then transfer the same theory to upfiring subs. I've heard it before, but I'm fairly skeptical to be honest. Suspensions loosen with playing in general, I can't imagine gravity effecting it to an audible amount even if they do sag.

Either way, I'd say that it probably doesn't matter much.

 

[RAM_Designs 5,000+ posts]

That would then transfer the same theory to upfiring subs. I've heard it before, but I'm fairly skeptical to be honest. Suspensions loosen with playing in general, I can't imagine gravity effecting it to an audible amount even if they do sag.
Either way, I'd say that it probably doesn't matter much.

Probably not until a couple of years down the road...but who keeps their subs for that long anyways? Maybe 5% of us?

 

[Doodaddy 10+ year member]

Probably not until a couple of years down the road...but who keeps their subs for that long anyways? Maybe 5% of us?

Round about there, and even then, they probably just sit in a garage with our greedy hands refusing to let them go. //content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif