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old skool malibu

Rockford Sub Box Rebuild

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old skool malibu

I have a 2012 VTX on the way and at this point I am going to run with the stock Rockford Sub. I ordered a 3 outlet heater and will be modifying the kick pannel to something similiar as Lil John's with 3 vents coming out the bottom under the sub. While I am at it do you think I should rebuild the crappy stock box? Any suggestions on dimensions, design etc?

post-4887-0-91086500-1329703425_thumb.jp

Edited by old skool malibu

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Bobby Light

Yeah because you might not even have a box, it could be sitting there in the kickpanel. I've seen them installed both ways from 08' on up. No joke. Either way I'd rebuild that stock box, it sucks and is to small for the sub.

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Earmark Marine

old skool,

Get both the sealed and bass-reflex recommendations from the manufacturer. If RF doesn't have some pre-designed models already then get the Thiele/Small parameters on the RF subwoofer from the manufacturer. From there you can get a couple of optimum alignments for sealed and bass-reflex specific to your woofer. Add in the construction materials and convert this to an external displacement so that you can determine what is the maximum that will fit.

At some point it will be the enclosure that determines the woofer performance and particularly the low frequency extension. If you plan on maintaining the RF woofer long term this will be worth the effort and expense to do it right.

David

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old skool malibu

Vb 1.00 cu. ft. http://www.rockfordfosgate.com/products/product_details.aspx?itemid=112086

F3 53.7 Hz

Qtc 0.82

Height 15.5 in.

Width 17.625 in.

Depth 12 in.

Spk. Cutout 10.95 in.

Spk. Depth 6.58 in.

Vd 0.053 cu. ft.

BoxAdvisor Target (sealed box) http://www.rockfordfosgate.com/products/product_details.aspx?itemid=112086

1 Internal Vb

0.053 Woofer Disp.

1.053 Total Cu. Ft.

I used 1/2 MDF on their tool but will go wth a Baltic Birch Plywood. Is 1/2 for Baltic Birch a recommended thickness? Any other suggestions?

Edited by old skool malibu

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martinarcher

Baltic Birch is pretty stout stuff. Mine is 1/2" and works fine. I did brace my box appropriately.

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Earmark Marine

old school,

I like the Qtc of .82 on the 1.0 cu.ft. enclosure.

I would strongly recommend a 0.75" material thickness. Internal stiffening braces can break the surface area into smaller fractions, increase rigidity and decrease cabinet resonance but also think of the integrity of the joints and seams with more connecting surface area. You are going to need glue and either staples or screws to assemble the enclosure. All plywood will have porous edges so I like the thicker material. And I would want a roundover on all exterior corners/edges so that a resin coating will be thicker as all coatings tend to withdrawal from hard edges. It will be easier to keep a router from making contact with staples or screws with a little thicker material. You are only increasing the three outer dimensions by 1/2" by using 3/4" stock.

David

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old skool malibu

The specs Rockford gives are (for a 1 cubic foot enclosure)

Height 15.5 in.

Width 17.625 in.

Depth 12 in.

Now when I run their box advisor tool I am aiming for 1.053

To hit this figure using 3/4 inch material I used

Height 15. in.

Width 15 in.

Depth 11.5 in.

(Not sure why this figure on the box building tool does not match their specs?)

To hit this figure I used (with 1/2 inch material)

Height 14.5. in.

Width 14.5 in.

Depth 11.0 in.

I really don’t know much about box building so any advise would be appreciated for the proper measurements. Please advise what my dimensions should be for 3/4 and 1/2 inch. I am going to use Baltic Birch plywood, not sure I really want to go to 3/4 using this material but if it’s strongly recommended I will. I was also thinking of going with a side firing box design and while I am at it was going to add a plexi glass face similar to Lil Johns. I assume I would have to go with a similar thickness, assuming I can find it.

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Earmark Marine

old skool,

Using .75" stock, external 13.5" X 13.5" X 11.5" = internal 12" X 12" X 10" = 1822.50 divided by 1728 (# of cu.in. in one cu.ft.) = 1.055 cu.ft. (close enough). So any shape of enclosure where the exterior dimensions equal 2587.50 cu.in. will be fine.

An 'air suspension' enclosure MUST absolutely be airtight. With an acrylic window you probably won't be able to use a caulk on the interior seams for cosmetic reasons. So .75" edges will be helpful.

David

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old skool malibu

Thanks David. I will trust your numbers, seems pretty straightforward. Using Rockford’s tool with those numbers it only gives me 0.83 cubic feet. If I did use an Acrylic window to get a seal would I be simply be relying on the screws ...lots of them? I will have a carpeted kick panel in front so even if the seal does not look pretty it won't be visible. Could I then use some form of adhesive?

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Earmark Marine

old skool,

Do not under-estimate the pressure that is created inside this sealed box.

First you will want to fill and sand the .75 plywood edge perfectly smooth that the acrylic window will rest against. No radius on this edge.

Then you will want to drill pass-thru holes that are countersunk for a flathead in the acrylic. Then in a corresponding pattern you will drill pilot holes in the enclosure's edge.

You want alot of screws for a good seal but too many too close together will cause the wood to split. If you will look close at the pattern and spacing used by liljohn in his photo, I would say that is a good template to follow.

I like to use a pure silicone sealer as a seamless gasket. But you have to work fast before it begins to gel. As an alternative you can use a closed-cell, .75 wide, adhesive-backed foam gasket. But its only as good as the four seams that butt together so you have to be precise.

David

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Earmark Marine

old skool,

Sorry, I made a mistake on the math. This morning after some sleep the fact that 12x12x10 internal is obviously less than a cubic foot jumped off the page at me.

The real external dimensions would be 13.5" X 13.5" X 14.25" with .75" stock in order to achieve 1.06 internal displacement. I just rounded up a bit for ease of construction. So any three dimensions that combine for 2587.50 cu. in. is still want you want.

David

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old skool malibu

If I a going to invest some money and time into this box it would be fantastic if it would work for a "real sub". Such as the Big 12. I looked on Exile's site and it states for a sealed enclosure SPL size you need 1 cu.ft. or SQ size 1.85 cu.ft. What is the difference between SPL and SQ? Assuming I can go with a 1 cu. ft enclosure will the box I am building for my Rockford then work as well for the Exile? http://www.exileaudio.com/products/bigsubs/?tab=specs

Also thinking of Etching the lexan with a Malibu or WS emblum. Any ideas on where I can get this done. Starting to wonder if this job should be left to the "pros"?

Edited by old skool malibu

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Bobby Light

If I a going to invest some money and time into this box it would be fantastic if it would work for a "real sub". Such as the Big 12. I looked on Exile's site and it states for a sealed enclosure SPL size you need 1 cu.ft. or SQ size 1.85 cu.ft. What is the difference between SPL and SQ? Assuming I can go with a 1 cu. ft enclosure will the box I am building for my Rockford then work as well for the Exile? http://www.exileaudio.com/products/bigsubs/?tab=specs

Also thinking of Etching the lexan with a Malibu or WS emblum. Any ideas on where I can get this done. Starting to wonder if this job should be left to the "pros"?

The smaller box will sound somewhat boomier. The sq size will be a more linear sound throught the frequency range. Shoot more for 1.25 cu ft on the sealed box and you'll like those results. I would actually entertain using the xi12d instead of the big 12 if you aren't going to be giving it 1000+ watts. The xi12d is an awesome sounding sub.

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Earmark Marine

old skool,

I hope you read my note about the corrected error in math.

What I am sharing pertains to all subwoofer drivers regardless of brand.

Box programs can be overly simplistic and they usually show the low frequency roll-off but very little else related to what is happening at an octave or so higher.

An SPL alignment is a smaller displacement and raises the Qtc (total woofer/enclosure system damping). The low frequency decline is premature. You will lose low bass extension. In a really undersized enclosure you will see a pronounced bump in the midbass thus a perceived increase in output. It may sound very live to some but will also sound peaky or ringy.

An SQ alignment is a larger displacement and lowers the system Qtc. The low frequency reach is extended. If you go TOO large you may have greater deep bass but you may sacrifice the midbass transients and the sub system may sound a bit dead. You may also lose perceived output because there is more material content in that upper octave and its a more efficient region to produce.

So for the best sound quality, balance and power handling you would like to end up with a system Qtc no lower than 0.7 and no higher than 1.0.

Now, every woofer manufacturer has their own set of priorities and they have the freedom to move around the parameters to get what they feel is best. Any over-focus on one discipline results in a compromise in another performance area. And that is okay. Designers have subjective differences just like everyone else. But you have to realize that two 'quality' woofers of the same size may have very different parameters and are optimized in very different enclosures. One woofer may be a high resonance/high Qts while another woofer may be a low Qts/low resonance. These are not the only Thiele Small parameters that you have to consider but if these numbers differ greatly these two woofers will probably not like the same enclosure.

David

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old skool malibu

The smaller box will sound somewhat boomier. The sq size will be a more linear sound throught the frequency range. Shoot more for 1.25 cu ft on the sealed box and you'll like those results. I would actually entertain using the xi12d instead of the big 12 if you aren't going to be giving it 1000+ watts. The xi12d is an awesome sounding sub.

This may be a good option..did you hear it in a boat or vehicle?

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liljohn

Make sure you account for the hight of the hot tubes. I missed this number by a quarter inch. Now I have to pull the stearing column when the box needs to come out. Stupid tilting steering wheel lever.

Edited by liljohn

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old skool malibu

Yes this is a concern. Being I dont have the new boat in my garage yet I have no idea about total height I can play with. My goal was to have 2 hot tubes below wth sub with one vent. I know you used PVC tubes so you may have given yourself a little more room? I was hoping on mounting the sub box on a stand so I would place the hot tubes below. What measurements did you use for your box and do you know off hand what your total height should have been? I assume you are runing the Big 12 in your box?

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Bobby Light

This may be a good option..did you hear it in a boat or vehicle?

I've heard them in boats sealed at 1.25 cu ft and ported at 2.0 cu ft. Sounds excellent either way.

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old skool malibu

I've heard them in boats sealed at 1.25 cu ft and ported at 2.0 cu ft. Sounds excellent either way.

I think I will stick with sealed. This is what I found on Exile's site

SPL Size .75 cu.ft.

SQ Size 1.4 cu.ft.

Just looking for the specs such at Qtc on their site..link wont me allow me to download.

Edited by old skool malibu

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liljohn

Yes this is a concern. Being I dont have the new boat in my garage yet I have no idea about total height I can play with. My goal was to have 2 hot tubes below wth sub with one vent. I know you used PVC tubes so you may have given yourself a little more room? I was hoping on mounting the sub box on a stand so I would place the hot tubes below. What measurements did you use for your box and do you know off hand what your total height should have been? I assume you are runing the Big 12 in your box?

I am running an IDQ 12. I used the pvc pipe to support the box and save the space. I missed the fact there the tilt lever hangs lower than the dash. The box was a rehab that I built for a Jl sub. 1.25 cubic feet I think.slot ported around 38 hrtz.

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martinarcher

If I a going to invest some money and time into this box it would be fantastic if it would work for a "real sub". Such as the Big 12. I looked on Exile's site and it states for a sealed enclosure SPL size you need 1 cu.ft. or SQ size 1.85 cu.ft. What is the difference between SPL and SQ? Assuming I can go with a 1 cu. ft enclosure will the box I am building for my Rockford then work as well for the Exile? http://www.exileaudi...subs/?tab=specs

Also thinking of Etching the lexan with a Malibu or WS emblum. Any ideas on where I can get this done. Starting to wonder if this job should be left to the "pros"?

I bought a pre-cut piece of 1" lexan for the back of a box I built for a car I had in high school. I covered the entire piece of lexan with contact paper. i then laid out my decal on top of the contact paper (Kicker Car Audio Logo). I then very slowly and very patiently cut out the logo by tracing my decal with a razor. I then peeled up the decal and contact paper to expose the lexan where I wanted the etching to be. I headed out to the garage and went over it twice with the sand blaster. It turned out perfect and cost me about $15 and an hour of my time. I'm sure there are other ways to skin the same cat, but it was cheap and worked very well for me.

BTW: for lexan to wood, use a 1" piece of double stick tape as a gasket. It works like a champ and will keep the box from leaking.

DSC02241.jpg

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Earmark Marine

old skool,

Keep in mind that 'Qts', which is listed, is related to the damping of the speaker independent of the enclosure. It is the 'Qtc', which is not listed for the various enclosure sizes, that is related to the system damping of the woofer in a given size of enclosure.

David

I think I will stick with sealed. This is what I found on Exile's site

SPL Size .75 cu.ft.

SQ Size 1.4 cu.ft.

Just looking for the specs such at Qtc on their site..link wont me allow me to download.

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old skool malibu

I bought a pre-cut piece of 1" lexan for the back of a box I built for a car I had in high school. I covered the entire piece of lexan with contact paper. i then laid out my decal on top of the contact paper (Kicker Car Audio Logo). I then very slowly and very patiently cut out the logo by tracing my decal with a razor. I then peeled up the decal and contact paper to expose the lexan where I wanted the etching to be. I headed out to the garage and went over it twice with the sand blaster. It turned out perfect and cost me about $15 and an hour of my time. I'm sure there are other ways to skin the same cat, but it was cheap and worked very well for me.

BTW: for lexan to wood, use a 1" piece of double stick tape as a gasket. It works like a champ and will keep the box from leaking.

DSC02241.jpg

Thanks Matt..looks good. Jeremy suggested a translucent decal..that would be a very easy fix. I assume I would have the Malibu clear and the background translucent?

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Bobby Light

I think I will stick with sealed. This is what I found on Exile's site

SPL Size .75 cu.ft.

SQ Size 1.4 cu.ft.

Just looking for the specs such at Qtc on their site..link wont me allow me to download.

If you go with an exile sub check with Brian on a recommended box size. Nobody knows more about the equipment then he does. For instance if Matt was to sidelight that plexi on that box you see the decal would shine in the LED color he sidelit it with. If you did the opposite the entire background would glow with the LED color and the emblem would be clear with no color, doesn't look good. If you want the emblem to glow with your color choice LED, PM me and I can give you some pointers. Similar to what I did on mine. I had mine emblems cut out on a CNC machine about 1/16" deep into the material on the backside.

Picture048.jpg

Edited by Bobby Light

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martinarcher

If you go with an exile sub check with Brian on a recommended box size. Nobody knows more about the equipment then he does. For instance if Matt was to sidelight that plexi on that box you see the decal would shine in the LED color he sidelit it with. If you did the opposite the entire background would glow with the LED color and the emblem would be clear with no color, doesn't look good. If you want the emblem to glow with your color choice LED, PM me and I can give you some pointers. Similar to what I did on mine. I had mine emblems cut out on a CNC machine about 1/16" deep into the material on the backside.

That box was lit with green neon tubes to match the car beck in the day before LED's were being used for accent lighting. It looked decent, but LEDs have sure changed the game as far as accent lighting goes for projects like this. Thumbup.gif The side lit sheets are sure the way to go now.

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