Motts
Dedicated LVC Member
Well there have been numerous questions on this. So I figured why not make a how to... if anyone has anything to add, pointers etc.. feel free..
when i built my first box... I bought a cheap one from the store I think it was like 30 bucks or so.. I then took the carpet off, and took the face piece off, the piece that has the holes for the speakers for it. I then modified or built my own. I used cardboard to make a template, and then made the face piece cut the speaker holdes.. and screwed it into the old box..
I now build all of my boxes from scratch..
Most speakers are different, some require different air space, some ported vented, some even sealed. Make sure you research that before you start building a box.
Do you already know what type of speakers your going to be using?
Building a box.
Because a subwoofer enclosure needs to be very strong we will use a composite wood rather than a natural wood. When building a custom subwoofer box you will want to use either MDF (medium density fiberboard) or if that's not available, a high grade particle board. Both are available at lumber yards and home improvement centers. Expect to pay $15-20 for a sheet (4' x 8'). You will want to hold the subwoofer enclosure together with a combination of wood glue and 1.5" drywall screws. Use a tube or silicone caulk to seal any gaps. This is very important when building subwoofer boxes.
How to Calculate Internal Box Volume
Area (rectangle) = Length x Width
Area (triangle) = 1/2 Length x Width
Area (circle) = 3.14 x Radius x Radius
Area (circle) = .785 x Diameter x Diameter
Volume (rectangular box) = Area (of one side) x Depth
Volume (triangular enclosure) = Area (triangle) x Depth
Volume (cylinder) = Area (circle) x Length
1728 Cubic Inches = 1 Cubic Foot
28 Liters = 1 Cubic Foot
For multiple-driver enclosures, you'll get the best performance by isolating each driver in a separate chamber. This prevents variations in speaker tolerances and input power from restricting system output. If building separate chambers isn't feasible, you can make sure that each driver receives the same amount of power by mounting two identical drivers in the same cavity and wiring them in parallel.
Draw out each piece of the enclosure before cutting so you don't waste material. Once individual sections have been cut, temporarily assemble the box to make sure the pieces fit snugly together. One option to consider at this juncture is the use of internal braces, which, depending on the overall size of the box, may result in a sturdier enclosure. Usually, 1.5 inch x 1.5 inch strips of material will suffice. Generally, you'll need to add braces only for boxes that have internal volumes of more than 5 cubic feet.
If all of the pieces fit and the edges match up, the box is ready for permanent assembly. First make sure all joints are free of debris. Then slowly run a bead of carpenter's glue along the line where you'll be making the first joint. Carefully assemble the two pieces and secure them using screws or nails. Use one screw every 6 inches or one nail every 3 inches. If you're using screws, drill pilot holes to prevent the wood from splitting. And for a more polished look, countersink the screws. (Note that the type of joint that you select is not critical as long as the box is strong and airtight.)
Continue assembling the box but don't attach the baffle board – the front panel that holds the speakers – until you've made sure the enclosure is sealed. To do this, fill a caulking gun with silicone sealant and run a bead along the inside of each joint. When you're finished caulking the box, secure the baffle board in place.
With the box assembled, you are now ready to cut the speaker openings and the vent, if you've chosen a vented design. I've always found that it's easier to work on the wood once the box is assembled. The vent tube can be made of plastic, cardboard, or – for a square or rectangular vent – wood. First, calculate the center of each hole and draw a circle of the appropriate diameter using your compass. Make 3/8-inch starter holes with a drill and then cut out the holes using a jigsaw.
Once the speaker and port openings are cut, put some silicone sealant on the tip of your index finger and reach into the enclosure to seal the inside joints of the baffle board. It's very important for the enclosure to be completely airtight; air leakage reduces the system's power-handling capacity and causes distortion. Once the joints are sealed, I recommend covering three adjacent inside walls – back, top, and bottom, for example – with 1 to 2 inches of polyfill (available at fabric stores for about $1.50 a bag). The use of filler will help minimize midbass resonances.
Before mounting the speakers, you'll need to drill a few holes. First make a hole at the bottom of the enclosure's rear panel for the speaker-cable connector. Then place the drivers in their respective holes and mark the location of each screw hole with a pencil. Remove the speaker and drill pilot holes. Before proceeding, remove all wood shavings. Snake a generous length of speaker cable through the hole in the rear of the enclosure. Then mount the connector of your choice (Radio Shack sells many different types) and, using your finger, seal the opening with silicone. Next, hook the speaker wire to the connector. If you don't use connectors (in the case of a permanent installation, perhaps), tie a knot in the speaker cable at the point where it exits the enclosure.
Now mount your crossover devices, and wire the cables to the speakers. (Don't forget about polarity.) With all wires securely in place (I recommend soldering), secure the drivers to the baffle board, using extreme caution – the last thing you need at this stage is a screwdriver-size hole in the speaker.
FIBERGLASS
What you would basically want to do is take out anything that you don't want to get resin on. The carpet comes out easily enough, and you WILL NOT get the resin out of it if you spill it or cut through plastic or anything. I highly recommend that you take out the carpeting.
First off, SAFETY FIRST!!!! A clean, well ventilated, and spark free (no smoking) work area are vital to this. You will need good rubber gloves, a couple of mixing bowls (not wax coated), several brushes that you can throw away, some grille cloth or fleece materials, a dust mask (not a necessity if the area is well ventilated, but I recommend it just the same), some body filler, and the resin materials.
Materials
> fiberglass resin & hardener
> fiberglass mat
> TacMat (a Dynamat Product)
> Dynashield (another Dynamat Product)
> > many disposable brushes sizes 1" to 3"
> disposable gloves
> "3M" Tape 1" and 2"
> paper or plastic coverings
> good ventilation area. (will leave car undrivable while fiberglass cures)
Step 1 Determine the purpose, shape and location
WARNING! Make arrangements for other transportation. Your car is not drivable until you remove the box. If you drive your car with wet fiberglass, you will get high and crash or get high, pass out then crash. Best bet start in the afternoon or evening and don't drive your car that night.
For most of us with the Maxima, the logical place for the fiberglass enclosure is the spare tire well. The first thing to do is to tape the area off to prevent any fiberglass or resin from getting on your car body. I highly recommend using 3M Brand tape. Trust me. Other tapes either don't stick or you can remove them. It really makes for an ugly mess. (Click on pics for larger images you can grab the top clear bar to move pics around)
I would like to give special thanks to Kevin for helping me with this. His website is www.sachelledesigns.com
Step 2 Rough cut TacMat
Now you are probable wondering what does this product have to do with fiberglass. I have built many fiberglass enclosure and they had problems. While they were light, they sounded "pingy" and, well, like fiberglass. Another problem is that when you mold a fiberglass part into the car, it will creak and rattle as you go over bumps and rail road tracks etc. That's because your car flexes and the box doesn't. This is where TacMat comes in. TacMat is a material made by the Dynamat guys. This material creates a barrier between the fiberglass and your car that damps the fiberglass (giving you that less fiberglass sound) and provides a cushion between your fiberglass and your car.
WARNING! Don't try to glass to just any type of foam material. TacMat is one of a small list of foams that will not be destroyed by fiberglass resin. Most will. And the results will be disastrous.
Step 3 Form into shape
A real easy step but necessary. Press the TacMat so that it follows the contours of the floor panel. In the corners, you could use a little double stick tape (you do not need too much and too much will present problems later) You could also cut the TacMat into different pieces and spray glue the edges together. If you take the later step, make sure to overlap the seams by about an inch.
Step 4 Make a top wood trim piece
This step will help you attach a wood baffle face to your fiberglass bottom. The example is only a 1/4 of an enclosure so essentially, you would build a wood ring. Make sure that the wood ring does not contort. It is important that it remain flat or your top plate will not seal correctly. This is the simplest way to finish the box. For more custom shapes of the top plate, this step is not necessary.
Step 5 First layer of fiberglass
This step is easy if you have worked with fiberglass before. If not, test out your efforts on a little test piece. The experience you gain is worth the material you waste. I have seen many people try a big project like this and mess it up and waste big bucks.
Work with little strips up to 4" x 10" in size. Use 8 oz material. If you have 4oz, double it up or make two passes. Make sure to completely saturate the fiberglass with resin. The trick is to use just enough resin to saturate the mat. Too much and it will add unnecessary wait and be a little bit weaker. Too little and it will be very strong. Make sure to get resin between the fiberglass, TacMat and your wood trim ring. (This is an important step)
NOTE: A word on hardener. I probably use too much hardener. I take the recommendations and double it (or more depending on the temperature) Don't add too much or you could catch the resin on fire.
Step 6 Let the resin harden
I know, you can't wait to finish. Do rush! this is the time that it is easiest to make a mistake. Notice the resin can on the wood ring. I put that there to add some weight to make sure that there is a good bond between the fiberglass and the wood ring. Make sure that the fiberglass is dry to the touch before moving to the next step. If you cannot wait, make sure that it is hard but tacky.
Step 7 Add glass to the underside of the wood ring
Use thin 1" strips and "tuck them between the underside of the wood ring and the fiberglass. This is where you wish you have the lip as close as possible to the edge of the fiberglass wall. (Makes it a whole lot easier) I use the tuck method.
Step 8 Add a second layer
Repeat "Step 5" with a second layer of 8oz cloth.
Step 9 Let it Dry
I know its killing you.
Step 10 Apply Dynashield
Dynashield is liquid Dynamat. This is a great use. The Dynashield sticks well to the fiberglass and further reduces that fiberglass "ring" that so many people have. Here I am using the kind from the Jug, but the can also works well. When using from the Jug, use a disposable brush and paint it on. I recommend about at least an 1/8" thick or about the thickness of a nickel. Dynashield is water soluble (won't catch on fire like other types of liquid damping material) and is non-toxic. It is also a great undercoating once dry.
Step 10 Let it dry
Dynashield with dry to the touch in about 2 hours. Complete dry time is about 24-48 hours. You could attach the top plate after a few hours. For best results wait overnight to use your enclosure.
Summary
At this point, the bottom half of the enclosure is basically complete. For a little better performance, you could resign over the top (light coat) and re-dynashield. When you install the top plate, make sure to seal properly with wood glue or silicon.
WARNING! What ever you do. DO NOT USE LIQUID NAILS! This material outgases and is highly flammable. In other words, if you were to use liquid nails and seal the top plate and bolt the woofer in and use is you will probably create a loud explosion and possible a fire. Don't laugh, more that one installer I know has had this happen to them.
Since you're happy with the fit now, look at the bottom. If you want to smooth it out by sanding it and filling it so that you can paint it, now is the time. If you don't want to paint it, then you don't need to fill the bottom, but you should fill the top to allow for the carpet or vinyl to be smooth. Put a good layer of body filler over the areas that aren't smooth to the touch and let it dry (it dries fairly quickly, so this shouldn't be too bad). Once the filler is dry, you will need to block sand it so that it is straight and smooth. The block will keep you from grooving the 'glass (but you must be careful to not groove the entire block into it by pressing too hard).
Once you're satisfied with the smoothness, cut your speaker hole and cover the enclosure as you like. I like to paint the bottom even if the top is covered with vinyl or cloth just because I figure people show them off. Takes a few extra minutes, but it's only 2 or 3 coats of paint, sooooo.....
any questions? Cheers :Beer
when i built my first box... I bought a cheap one from the store I think it was like 30 bucks or so.. I then took the carpet off, and took the face piece off, the piece that has the holes for the speakers for it. I then modified or built my own. I used cardboard to make a template, and then made the face piece cut the speaker holdes.. and screwed it into the old box..
I now build all of my boxes from scratch..
Most speakers are different, some require different air space, some ported vented, some even sealed. Make sure you research that before you start building a box.
Do you already know what type of speakers your going to be using?
Building a box.
Because a subwoofer enclosure needs to be very strong we will use a composite wood rather than a natural wood. When building a custom subwoofer box you will want to use either MDF (medium density fiberboard) or if that's not available, a high grade particle board. Both are available at lumber yards and home improvement centers. Expect to pay $15-20 for a sheet (4' x 8'). You will want to hold the subwoofer enclosure together with a combination of wood glue and 1.5" drywall screws. Use a tube or silicone caulk to seal any gaps. This is very important when building subwoofer boxes.
How to Calculate Internal Box Volume
Area (rectangle) = Length x Width
Area (triangle) = 1/2 Length x Width
Area (circle) = 3.14 x Radius x Radius
Area (circle) = .785 x Diameter x Diameter
Volume (rectangular box) = Area (of one side) x Depth
Volume (triangular enclosure) = Area (triangle) x Depth
Volume (cylinder) = Area (circle) x Length
1728 Cubic Inches = 1 Cubic Foot
28 Liters = 1 Cubic Foot
For multiple-driver enclosures, you'll get the best performance by isolating each driver in a separate chamber. This prevents variations in speaker tolerances and input power from restricting system output. If building separate chambers isn't feasible, you can make sure that each driver receives the same amount of power by mounting two identical drivers in the same cavity and wiring them in parallel.
Draw out each piece of the enclosure before cutting so you don't waste material. Once individual sections have been cut, temporarily assemble the box to make sure the pieces fit snugly together. One option to consider at this juncture is the use of internal braces, which, depending on the overall size of the box, may result in a sturdier enclosure. Usually, 1.5 inch x 1.5 inch strips of material will suffice. Generally, you'll need to add braces only for boxes that have internal volumes of more than 5 cubic feet.
If all of the pieces fit and the edges match up, the box is ready for permanent assembly. First make sure all joints are free of debris. Then slowly run a bead of carpenter's glue along the line where you'll be making the first joint. Carefully assemble the two pieces and secure them using screws or nails. Use one screw every 6 inches or one nail every 3 inches. If you're using screws, drill pilot holes to prevent the wood from splitting. And for a more polished look, countersink the screws. (Note that the type of joint that you select is not critical as long as the box is strong and airtight.)
Continue assembling the box but don't attach the baffle board – the front panel that holds the speakers – until you've made sure the enclosure is sealed. To do this, fill a caulking gun with silicone sealant and run a bead along the inside of each joint. When you're finished caulking the box, secure the baffle board in place.
With the box assembled, you are now ready to cut the speaker openings and the vent, if you've chosen a vented design. I've always found that it's easier to work on the wood once the box is assembled. The vent tube can be made of plastic, cardboard, or – for a square or rectangular vent – wood. First, calculate the center of each hole and draw a circle of the appropriate diameter using your compass. Make 3/8-inch starter holes with a drill and then cut out the holes using a jigsaw.
Once the speaker and port openings are cut, put some silicone sealant on the tip of your index finger and reach into the enclosure to seal the inside joints of the baffle board. It's very important for the enclosure to be completely airtight; air leakage reduces the system's power-handling capacity and causes distortion. Once the joints are sealed, I recommend covering three adjacent inside walls – back, top, and bottom, for example – with 1 to 2 inches of polyfill (available at fabric stores for about $1.50 a bag). The use of filler will help minimize midbass resonances.
Before mounting the speakers, you'll need to drill a few holes. First make a hole at the bottom of the enclosure's rear panel for the speaker-cable connector. Then place the drivers in their respective holes and mark the location of each screw hole with a pencil. Remove the speaker and drill pilot holes. Before proceeding, remove all wood shavings. Snake a generous length of speaker cable through the hole in the rear of the enclosure. Then mount the connector of your choice (Radio Shack sells many different types) and, using your finger, seal the opening with silicone. Next, hook the speaker wire to the connector. If you don't use connectors (in the case of a permanent installation, perhaps), tie a knot in the speaker cable at the point where it exits the enclosure.
Now mount your crossover devices, and wire the cables to the speakers. (Don't forget about polarity.) With all wires securely in place (I recommend soldering), secure the drivers to the baffle board, using extreme caution – the last thing you need at this stage is a screwdriver-size hole in the speaker.
FIBERGLASS
What you would basically want to do is take out anything that you don't want to get resin on. The carpet comes out easily enough, and you WILL NOT get the resin out of it if you spill it or cut through plastic or anything. I highly recommend that you take out the carpeting.
First off, SAFETY FIRST!!!! A clean, well ventilated, and spark free (no smoking) work area are vital to this. You will need good rubber gloves, a couple of mixing bowls (not wax coated), several brushes that you can throw away, some grille cloth or fleece materials, a dust mask (not a necessity if the area is well ventilated, but I recommend it just the same), some body filler, and the resin materials.
Materials
> fiberglass resin & hardener
> fiberglass mat
> TacMat (a Dynamat Product)
> Dynashield (another Dynamat Product)
> > many disposable brushes sizes 1" to 3"
> disposable gloves
> "3M" Tape 1" and 2"
> paper or plastic coverings
> good ventilation area. (will leave car undrivable while fiberglass cures)
Step 1 Determine the purpose, shape and location
WARNING! Make arrangements for other transportation. Your car is not drivable until you remove the box. If you drive your car with wet fiberglass, you will get high and crash or get high, pass out then crash. Best bet start in the afternoon or evening and don't drive your car that night.
For most of us with the Maxima, the logical place for the fiberglass enclosure is the spare tire well. The first thing to do is to tape the area off to prevent any fiberglass or resin from getting on your car body. I highly recommend using 3M Brand tape. Trust me. Other tapes either don't stick or you can remove them. It really makes for an ugly mess. (Click on pics for larger images you can grab the top clear bar to move pics around)
I would like to give special thanks to Kevin for helping me with this. His website is www.sachelledesigns.com
Step 2 Rough cut TacMat
Now you are probable wondering what does this product have to do with fiberglass. I have built many fiberglass enclosure and they had problems. While they were light, they sounded "pingy" and, well, like fiberglass. Another problem is that when you mold a fiberglass part into the car, it will creak and rattle as you go over bumps and rail road tracks etc. That's because your car flexes and the box doesn't. This is where TacMat comes in. TacMat is a material made by the Dynamat guys. This material creates a barrier between the fiberglass and your car that damps the fiberglass (giving you that less fiberglass sound) and provides a cushion between your fiberglass and your car.
WARNING! Don't try to glass to just any type of foam material. TacMat is one of a small list of foams that will not be destroyed by fiberglass resin. Most will. And the results will be disastrous.
Step 3 Form into shape
A real easy step but necessary. Press the TacMat so that it follows the contours of the floor panel. In the corners, you could use a little double stick tape (you do not need too much and too much will present problems later) You could also cut the TacMat into different pieces and spray glue the edges together. If you take the later step, make sure to overlap the seams by about an inch.
Step 4 Make a top wood trim piece
This step will help you attach a wood baffle face to your fiberglass bottom. The example is only a 1/4 of an enclosure so essentially, you would build a wood ring. Make sure that the wood ring does not contort. It is important that it remain flat or your top plate will not seal correctly. This is the simplest way to finish the box. For more custom shapes of the top plate, this step is not necessary.
Step 5 First layer of fiberglass
This step is easy if you have worked with fiberglass before. If not, test out your efforts on a little test piece. The experience you gain is worth the material you waste. I have seen many people try a big project like this and mess it up and waste big bucks.
Work with little strips up to 4" x 10" in size. Use 8 oz material. If you have 4oz, double it up or make two passes. Make sure to completely saturate the fiberglass with resin. The trick is to use just enough resin to saturate the mat. Too much and it will add unnecessary wait and be a little bit weaker. Too little and it will be very strong. Make sure to get resin between the fiberglass, TacMat and your wood trim ring. (This is an important step)
NOTE: A word on hardener. I probably use too much hardener. I take the recommendations and double it (or more depending on the temperature) Don't add too much or you could catch the resin on fire.
Step 6 Let the resin harden
I know, you can't wait to finish. Do rush! this is the time that it is easiest to make a mistake. Notice the resin can on the wood ring. I put that there to add some weight to make sure that there is a good bond between the fiberglass and the wood ring. Make sure that the fiberglass is dry to the touch before moving to the next step. If you cannot wait, make sure that it is hard but tacky.
Step 7 Add glass to the underside of the wood ring
Use thin 1" strips and "tuck them between the underside of the wood ring and the fiberglass. This is where you wish you have the lip as close as possible to the edge of the fiberglass wall. (Makes it a whole lot easier) I use the tuck method.
Step 8 Add a second layer
Repeat "Step 5" with a second layer of 8oz cloth.
Step 9 Let it Dry
I know its killing you.
Step 10 Apply Dynashield
Dynashield is liquid Dynamat. This is a great use. The Dynashield sticks well to the fiberglass and further reduces that fiberglass "ring" that so many people have. Here I am using the kind from the Jug, but the can also works well. When using from the Jug, use a disposable brush and paint it on. I recommend about at least an 1/8" thick or about the thickness of a nickel. Dynashield is water soluble (won't catch on fire like other types of liquid damping material) and is non-toxic. It is also a great undercoating once dry.
Step 10 Let it dry
Dynashield with dry to the touch in about 2 hours. Complete dry time is about 24-48 hours. You could attach the top plate after a few hours. For best results wait overnight to use your enclosure.
Summary
At this point, the bottom half of the enclosure is basically complete. For a little better performance, you could resign over the top (light coat) and re-dynashield. When you install the top plate, make sure to seal properly with wood glue or silicon.
WARNING! What ever you do. DO NOT USE LIQUID NAILS! This material outgases and is highly flammable. In other words, if you were to use liquid nails and seal the top plate and bolt the woofer in and use is you will probably create a loud explosion and possible a fire. Don't laugh, more that one installer I know has had this happen to them.
Since you're happy with the fit now, look at the bottom. If you want to smooth it out by sanding it and filling it so that you can paint it, now is the time. If you don't want to paint it, then you don't need to fill the bottom, but you should fill the top to allow for the carpet or vinyl to be smooth. Put a good layer of body filler over the areas that aren't smooth to the touch and let it dry (it dries fairly quickly, so this shouldn't be too bad). Once the filler is dry, you will need to block sand it so that it is straight and smooth. The block will keep you from grooving the 'glass (but you must be careful to not groove the entire block into it by pressing too hard).
Once you're satisfied with the smoothness, cut your speaker hole and cover the enclosure as you like. I like to paint the bottom even if the top is covered with vinyl or cloth just because I figure people show them off. Takes a few extra minutes, but it's only 2 or 3 coats of paint, sooooo.....
any questions? Cheers :Beer
