Box help...8 Soundqubed HDC4 18s


Will.......

Member
Aug 12, 2016
48
0
Fort Worth, Tx
I need some help with a quite extreme box.

So far, due to space limitations, i am thinking 2 boxes like this on top of each other.(image link)

Is this a good type of box for music or spl? It will be loud either way, i know, but what are your other thoughts on the box? I need box tuned in the 30s for music.

By the way I am working with a large crew cab tundra. The maximum box size is approximately...42" deep,62" wide, and 47" tall.

If this isnt a good box, given my needs, then what would you suggest?

Lots of questions (sorry) but please respond, even if you only answer one.

(B4 this gets started, dont ask "who needs 8 18s?" Because i do LOL)

 

hispls

CarAudio.com Veteran
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Sep 10, 2009
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Central Maine
I need some help with a quite extreme box.
So far, due to space limitations, i am thinking 2 boxes like this on top of each other.(image link)

Is this a good type of box for music or spl? It will be loud either way, i know, but what are your other thoughts on the box? I need box tuned in the 30s for music.

By the way I am working with a large crew cab tundra. The maximum box size is approximately...42" deep,62" wide, and 47" tall.

If this isnt a good box, given my needs, then what would you suggest?

Lots of questions (sorry) but please respond, even if you only answer one.

(B4 this gets started, dont ask "who needs 8 18s?" Because i do LOL)
Looks to me like you won't have near enough volume to really do 8 18's properly. Your "max space" is about 70 cubic feet. Less 20 cube (10 sheets of 3/4 wood) probably a low estimate, and you're at 50, eat up enough for an adequate port and you're down to under 40. I'd say you should reconsider going with only 4 18s or 6-8 15s.

Really though if you had 8 18's even in too small sealed box and threw enough power at it it would be very loud, but you're going to be using way more equipment than necessary to get to the same place.

 

Jeffdachef

Gunz That Turn on Nunz
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Feb 5, 2013
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South Coast Metro, CA
Forgot to add the video on youtube that inspired me...
he has 1.5 x the amount of airspace to work with. You'll have strangled subs in your vehicle.

 

Will.......

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Aug 12, 2016
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Fort Worth, Tx
  • Thread Starter Thread Starter
  • #5
I don't think yall are talking about this sub. Yes your right he does have more airspace, but that dosent mean i can't fit them. Not all 18s take up lots of air.

According to this (HDC3 & HDC4 Optimum Enclosure Size - Subwoofers / Enclosures - SMD Forum) post by AMI Customs since I am running 4k watts rms i only need 5.5 cubes per sub and 93 sq. In. Port per sub. If I tune in 35-38hz range this is definatly possible.

If you are about to ask where my electrical and amps are going, i am putting them in the bed.

 

Jeffdachef

Gunz That Turn on Nunz
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Feb 5, 2013
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South Coast Metro, CA
I don't think yall are talking about this sub. Yes your right he does have more airspace, but that dosent mean i can't fit them. Not all 18s take up lots of air.
According to this (HDC3 & HDC4 Optimum Enclosure Size - Subwoofers / Enclosures - SMD Forum) post by AMI Customs since I am running 4k watts rms i only need 5.5 cubes per sub and 93 sq. In. Port per sub. If I tune in 35-38hz range this is definatly possible.

If you are about to ask where my electrical and amps are going, i am putting them in the bed.
You misjudge the amount of bracing and doubling up on layers to keep a box with 8 18s from falling apart especially on the low lows I already know what the hdc4s are and what they need to get loud. I saw that thread right when it first came out...... Plain and simple you still dont have enough space. 6 hdc4 18s would be better and louder in the amount of space you have.

No box flex = higher dbs

No to mention batteries and amps. You dont nearly have enough room as you think man. People always misjudge and fk up on their builds.

 

hispls

CarAudio.com Veteran
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Sep 10, 2009
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I don't think yall are talking about this sub. Yes your right he does have more airspace, but that dosent mean i can't fit them. Not all 18s take up lots of air.
According to this (HDC3 & HDC4 Optimum Enclosure Size - Subwoofers / Enclosures - SMD Forum) post by AMI Customs since I am running 4k watts rms i only need 5.5 cubes per sub and 93 sq. In. Port per sub. If I tune in 35-38hz range this is definatly possible.

If you are about to ask where my electrical and amps are going, i am putting them in the bed.
Hey, if you know best already why even ask? Buy some wood and start building, let us know how this pans out for you.

 

Will.......

Member
Aug 12, 2016
48
0
Fort Worth, Tx
  • Thread Starter Thread Starter
  • #9
You misjudge the amount of bracing and doubling up on layers to keep a box with 8 18s from falling apart especially on the low lows I already know what the hdc4s are and what they need to get loud. I saw that thread right when it first came out...... Plain and simple you still dont have enough space. 6 hdc4 18s would be better and louder in the amount of space you have.

No box flex = higher dbs

No to mention batteries and amps. You dont nearly have enough room as you think man. People always misjudge and fk up on their builds.
Ok, better safe than sorry. What do yall think about 8 HDC4 15s with 4k input. According to that link above, for an spl build they need 3.75 cubes a piece 17 sq in port per cube. It also says tuning 35-38hz. This sounds possible with my space.

 

Will.......

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Aug 12, 2016
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Fort Worth, Tx
  • Thread Starter Thread Starter
  • #10
Hey, if you know best already why even ask? Buy some wood and start building, let us know how this pans out for you.
Sorry man, didnt mean to disrespect you or anything. As you can see now ive switched to 8 15s

 

hispls

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Sorry man, didnt mean to disrespect you or anything. As you can see now ive switched to 8 15s
If you're willing to take any advice, build the top back and sides then see how much space you really have left over after it's strong enough to take a bomb blast. As Jeff said, you probably don't have nearly as much space as you think you do (we have all been there) and cramming too much cone area in too small a box will give you poor results.


This box was built for 9 15's and it's a very large box in a big van. Even with 3 subs blown and their holes plugged up it does the same numbers on the meter with only 6 subs. Also worth mentioning, that van has solid rubber armored truck tires and a LOT of custom suspension work done so that it can actually drive.

Cramming too much cone area in too little space might look impressive but performance will suffer and you're wasting money on equipment you didn't need.

There's some big dogs in Texas, if you're serious about this, you would do well to meet up with some of those local guys that have done big builds before and get some help and advice. **** looks cool on youtube, but I think you might be way underestimating what you're getting into here.

 

Hertz Mafia

FEATHER RUFFLER
Jul 2, 2016
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Michigan
4 15s in big box doing a 160db is way more impressive then 8 18s doing a 160db.

From the way your posting I think u should start smaller and work your way up..we all didn't just start out and spend $20,000-$30,000 on a proper install..

alts

Batts

Wire

Lugs

Subs

Amps

Speakers

Wood

Not trying to discourage you but I hope you have deep pockets and know what your doing because if you have a b pillar build this size and don't do 60s+ these days your a failure.

 

dbjunior

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Jun 26, 2009
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ma
Highly recommended to build a shell first then your baffle and port. Once that is built you will need to see how much area is left to work with after a good amount of port is used. If you want crazy loud id go with as many 12's will fit with what space you have available.

 

Will.......

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Aug 12, 2016
48
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Fort Worth, Tx
  • Thread Starter Thread Starter
  • #14
Ok thanks for yalls help so far. I need to rethink this whole thing and start from scratch. But to clear some stuff up, this is not my first time with car audio, right now i am running 2 15s on 3k doing up to 150db. I do not have enough money to work up to large wall builds, so i have to make a big leap to hit upper 150s. I hope this is not too much of a leap, but so far everyone seems to be helpful.

It sounds like i need to build a shell then find exactly how much airspace i have.

 

kr15

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Determine your airspace. I would not even bother considering 8 18s. Maybe 8 15s or even like 12 12s

 

Popwarhomie

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What do yall think about 8 HDC4 15s with 4k input.
ONE HDC4 will handle a "4k".. I think you need to rethink everything if your planning on running a single 4k.

 

hispls

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if you have a b pillar build this size and don't do 60s+ these days your a failure.
Speaking of which, what happened to Alex?

Ok thanks for yalls help so far. I need to rethink this whole thing and start from scratch. But to clear some stuff up, this is not my first time with car audio, right now i am running 2 15s on 3k doing up to 150db. I do not have enough money to work up to large wall builds, so i have to make a big leap to hit upper 150s. I hope this is not too much of a leap, but so far everyone seems to be helpful.
You have actually metered this on a termlab? What subs? What amp? At what frequency? 150 to 158 is a very very big leap and high 150's won't come cheap or easy.

ONE HDC4 will handle a "4k".. I think you need to rethink everything if your planning on running a single 4k.
I didn't catch that. I assumed he meant a 4K per sub?

 

tymoto21

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Apr 15, 2008
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wisconsin
one huge part that i think was missed so far is baffle space.

sure you can build a clam sorta baffle but that also eats up precious cf.

and if you going for a clam style baffle its been very trendy to just do a 4th order.

imo 9 12's flat wall with 27 cf 20sq" o port per (maybe make a plug to lower tuning if you need to)

4k per sub will get roudy

if you worked at it you could probably fit 8 15's on a flat wall but would be a bit harder

 

Chris McNeeley

Red Light Ear Rapist
Jul 30, 2016
331
0
Toledo, ohio
Im currently rebuilding to 4 hdc4 18s in 25 cubes net, bpillar flat wall.

 

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