New build. :) memphis mojo 15

[on1wheel01 10+ year member]

You can take what they recomment and throw it out the door. Do what the guys on here suggest thats how youl get really loud. Just sayin.......

And yea u shoulda done some bracing.

 

[XORstatus 10+ year member]

I can still do bracing, Is there a link or a tread where I can read some information about bracing?

How often should one brace under what conditions?

 

[on1wheel01 10+ year member]

I use bracing no matter what. I use 1" dowels in my boxes. What part of nc r u in. I may be able to lend a hand I'm near charlotte. I also have a mojo 15 but have 2 if u ever wanna hear what they sound like.

 

[XORstatus 10+ year member]

Im south of raleigh, you're pretty far away but I appreciate the offer!

Ive had a MOJO previously but sold it when I got my FI BTL 18. For some reason I have become nostalgic recently and I just HAD TO HAVE another one.

My first box was designed by RADIO ACTIVE in raleigh I have no idea what it was tuned to but the guy there DEF tuned it for SPL.

I have different desires from my audio system now so I designed a different box, one that will be tight and clean while simultaneously delivering MOJO fabled power.

Here are some pictures of the MOJO box and then the box that I built for the FI.

 

[XORstatus 10+ year member]

 

[akheathen Premium Member]

this new box has a port area of 7.3"^2 per cu......... notice both those other boxes have a better port area?

 

[THATpurpleKUSH 5,000+ posts]

Memphis recommends 30 sq in of port area. I made that decision on their recommendations.Im not saying that they are completely correct, just giving you and Idea of how/where I started.

Why do you think the port is too small?

Im not implying that your wrong, just interested in getting a more holistic ideal.

I was thinking of supports but I don't know the rule or guide lines of their distribution.

If you have any Ideas about it would you please share them?

AS ALWAYS thank you for the critiques.

I say this based on my experience building boxes and from what I have seen others do. On a higher excursion woofer (xmax > ~15mm) a bigger port will help to increase the amount of air moved. When doing a slot port you should aim for 12-16sq in per cu/ft of airspace. A woofer like yours would be towards the upper end of that. It looks like your box is somewhere in the 3.0-3.5cu/ft range so assuming that on the low end of that figure you should have 36-48sq in and the upper end would be 42-56sq in. By having a small port you are more at risk for port noise (whistling or chuffing) because of the higher air velocity, especially if you have hard edges at the port openings.

I like to go excess with bracing because the box can never be too strong imo. I use 2x2 or 1.5in dowls. The 2x2s are cheaper but take up more airspace.

Some examples of how I have done it:

and when you add bracing you need to subtract its displacement or it will throw off tuning.

 

[Corey J. 10+ year member]

You need a router bro. Other than that , some 45s in the corners, route the port and some sort of bracing top to bottom preferred. Enjoy that sub, the new ones are not even close to their level !

Box I just built for 2 C3 15s in a Pontiac vibe.

 

[XORstatus 10+ year member]

 

[on1wheel01 10+ year member]

One recommendation I can make. Try firing forward and seal it off completely. I built a box for a local customer had a nightshade v2 18 and saz3500 in a cadillac. Was so stupid loud and cut down on rattle

 

[elancohen92 10+ year member]

At most they were off by 1/16 nothing that my sander couldnt hande //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Im gonna fiberglass resin the internals SHOULD make this baby SCREAM, its tuned LOW less than 33 Hz.

Ill keep you guys informed.

Nope, only way is you have like 8 sq in of port area per foot. or i would say your tuned about 44-48hz at the length of your port

 

[elancohen92 10+ year member]

if you had proper port area

 

[XORstatus 10+ year member]

One recommendation I can make. Try firing forward and seal it off completely. I built a box for a local customer had a nightshade v2 18 and saz3500 in a cadillac. Was so stupid loud and cut down on rattle

I dont know what this means?

 

[on1wheel01 10+ year member]

Fire sub and port forward into the cabin and seal the sides off with t shirts or towels. U may like how it sounds.

 

[THATpurpleKUSH 5,000+ posts]

i would say your tuned about 44-48hz at the length of your port

This....the port length is wayy too small, if you have 30sq in of port with 3 cu/ft then youd need about 20in of port length for 33hz, it drops to 16.5 with 3.5 cu/ft, yours looks like its more like 12-13in long