Helping port noise....

[adas Pro Seller]

Hey guys, just build a underseat box so i was a little limited on space for massive port area

....anyways, built a 2cu.ft box with 24sq" of port 8x3x18"

below 34hz comes the nasty port noise //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

Question...what can i do to help it in this box.

will resin help?

figure it'll maybe reduce turbulence....

round over the edges even more?

box sounds awesome, figured 12sq/in would be enough per cube but apparently not for these 1508's LOL

Click to read more...

 

[helotaxi 5,000+ posts]

Three ways to reduce port noise:

1) increase port area

2) flare all openings, inside and out

3) reduce power

What does the tuning work out to? Seems like a really short port. I've got a feeling that you're not getting port noise but rather mechanical noise caused by the sub unloading below tuning.

 

[Canaan 10+ year member]

Pics of box?

I do think that by far a larger port will help alot.

12sqin/cuft is pretty small w/ the DD1508's.

They like quick a bit more port area.

 

[SpeedEuphoria 10+ year member]

flaring the port opening inside and out should be your 1st step

if not you may have to look into external aeroports

 

[RAM_Designs 5,000+ posts]

Three ways to reduce port noise:
1) increase port area

2) flare all openings, inside and out

3) reduce power

What does the tuning work out to? Seems like a really short port. I've got a feeling that you're not getting port noise but rather mechanical noise caused by the sub unloading below tuning.

I got ~37hz.

 

[adas Pro Seller]

well, the box sounds freakin awesome....yes, wanted some more port area but it worked out pretty nice.

Not mechanical noise, I'm no 1508 novice //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Tuned it to right about 37hz just as RAM just said...

Both ends of port are rounded off.....i might give em more flare tomarrow.

was just wondering mostly if resin will help?

heres pics. quality blows im sorry

 

[helotaxi 5,000+ posts]

You're getting noise 3hz below tuning. The subs are unloading and the noise you hear is a result. If it were really a port noise issue you would hear it right at tuning and slightly above where port velocity is highest.

 

[adas Pro Seller]

Actually Helo, port velocity is highest around 30-32hz. Seems that for some reason the tuning is lower real world then on paper. The subs arent unloading around that freq, as thats really where the subs move the least. meaning the box is techincally tuned to 30hz? doesnt seem right.

ima try to stuff some crap in the box to raise tuning see how it does.

 

[Ray21 10+ year member]

One side of the hump may be acting as part of the port, effectively increasing port length.

I'm surprised you're getting port noise; how close is the port exit to the side of the truck?