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4th order question


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Hey guys just doing the draw up for my 4th order. I no Cj helped me out in my last post on sealed specs so here is why I'm Thinking going on his recommendation. If you don't know I'm planning on running 4 dc audio lvl 5 15s m2 with ab 1100.1

1.75cubes sealed so sealed portion is going to be 7cubes. Sub mounted outside (so I can smell the coil ) then 18.5 ported without sub displacement so 17.5 with. With 400square inches of port. No I'm trying to figure out what to tune to. The box is about 26.72 cubes internally all together and I did 16" per cube is this correct. Hope I did this right. I have a pic of a drawing but not sure how to post it. Thanks for he help in advance

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Need more port imo

Closer to 18 or 20 inches of port per cube

SCSB

Santa Cruz Speaker Box

Build logs:

Daily Driver Lemon Marquis

2 american bass 750.1s

350.4 on 14 focal 6.5s

sq 945 on 4 hertz tweeters

Mystery subs peepwall.gif

http://www.stevemead...__fromsearch__1

The Mustang 'dubbed' Shirley the project from bullet holes to badass

http://www.stevemead...cond-skin-time/

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Start with 18" per and work your way down.

2007 M/T Honda Civic Coupe EX

(4) Sundown Audio X-8's

(2) Ampere Audio 3800.1's

(3) Stinger SPV-44 Batteries

(1) Mechman 240

3:1 Ratio 4th order sealed from the trunk

TEAM NWSPL

Best termlab scores to date in Honda trunk:
151.7db legal (official) IASCA trunk 3 class

Best termlab scores to date in my walled Subie:
152.9db legal (unofficial) IASCA advanced 2 class
155db outlaw

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I'm at 28 inches of port per cube with my 4th

My buddy bill is right around 20 with a similar box to urs

I would at least do 20 but that's just me 18 would work

SCSB

Santa Cruz Speaker Box

Build logs:

Daily Driver Lemon Marquis

2 american bass 750.1s

350.4 on 14 focal 6.5s

sq 945 on 4 hertz tweeters

Mystery subs peepwall.gif

http://www.stevemead...__fromsearch__1

The Mustang 'dubbed' Shirley the project from bullet holes to badass

http://www.stevemead...cond-skin-time/

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I agree. I started with 18 here and that's what my box seemed to like.

I've also heard that half of the cone area of your subs is a place to start. But take that with a grain of salt.

2007 M/T Honda Civic Coupe EX

(4) Sundown Audio X-8's

(2) Ampere Audio 3800.1's

(3) Stinger SPV-44 Batteries

(1) Mechman 240

3:1 Ratio 4th order sealed from the trunk

TEAM NWSPL

Best termlab scores to date in Honda trunk:
151.7db legal (official) IASCA trunk 3 class

Best termlab scores to date in my walled Subie:
152.9db legal (unofficial) IASCA advanced 2 class
155db outlaw

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It all comes down to port velocity..... Which is determined by port area and tuning frequency

You need a specific number....

Also very important and a good quote from Hackmunch

"Port flares

Well enginering studies show that a 20% radius is optimal for spl and cutiing down turbulance to an absolute minimium. So a proper 8" flare should have a minimium of 1.6" radius . 8" + 3.2" =11.2 plus flat for mounting. Anyone making pvc flares (won't mention any names)with less than 20% radius is really wasting peoples time and money. Don't get me wrong a little flare is better than nothing but a proper flare is wayyy better than a little one."

SCSB

Santa Cruz Speaker Box

Build logs:

Daily Driver Lemon Marquis

2 american bass 750.1s

350.4 on 14 focal 6.5s

sq 945 on 4 hertz tweeters

Mystery subs peepwall.gif

http://www.stevemead...__fromsearch__1

The Mustang 'dubbed' Shirley the project from bullet holes to badass

http://www.stevemead...cond-skin-time/

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