Impact M4-15i Baltic Birch 4.0cuft Midbass Flat-Pack for 15" woofers

Note April 25, 2022: Price is per cabinet, minimum order is two. 

Shipping weight surcharges from FedEx and UPS have recently changed. To keep each shipping box under 50lbs I package up a pair of cabinets in 3 boxes.  So these cabinets have to be ordered in pairs.  Most people order 2 anyway so I don't think this will be an issue.  If you ordered a single in the past and only need one more, please contact me.  There are only 6 left and due to current Baltic birch prices these won't be able to be offered again at this price.  So you should buy the quantity you need now.

The Impact M4-15i by Denovo Audio is a 4.0 cubic foot midbass module flat pack made from 13 ply 3/4" Baltic birch. It's an extremely solid cabinet with six full depth angled braces and comes with a 1.5" thick front baffle. 

Works with virtually all 15" subwoofers and woofers.  A half inch deep recessed cutout of 15.38" allows for most woofer or subwoofer frames to be flush mounted.  Some people prefer not to flush mount their woofer, or the diameter is bigger due to rubber gaskets around the frame.  That's no problem with this enclosure because you can simply flip the two baffles over before gluing them to the cabinet which allows you to mount your woofer directly on the front. 

Every panel is cut with an automated CNC router so that the pieces fit together perfectly in rabbet joints and dado grooves. Not only does this make assembly much easier and more accurate, but also gives you a stronger enclosure because there's more surface area for the glue to bond to.

This cabinet gives you a net internal volume around 4.0cuft after subtracting the woofer and braces. The well thought out bracing system allows you to assemble the entire cabinet quickly and easily with no need for screws or nails. 

Product Highlights:

• Made from 13 ply 3/4" Baltic birch that is Carb 2 compliant
• Four 3" ports tune the cabinet at 38hz (or higher if ports are cut shorter)
• Flared ports are used to reduce the port noise known as 'chuffing'
• 6 full depth angled braces eliminate all panel flex
• 1.5" thick reversable front panel for added strength
• CNC cut for incredible accuracy
• Rabbet joints and dado grooves help align panels for easy assembly

Note: I did not have the CNC company cut holes for terminals because everyone likes using something different. Terminals, binding posts, and/or speaker spikes can be shipped for free if you order them at the same time you order this flat pack.

Recommended Tools:

• Clamps that open as big as the longest side of the flat pack.
• A mallet (or a small piece of wood and hammer) to lightly tap pieces into place if needed.
• Quality wood glue like Titebond. Some people use PL adhesive.
• Sandpaper or sanding block for smaller cabinets, but a power sander speeds things up a lot.
• Some prefer to use brad nailers for quick assembly, but clamps are just fine with no need for nails or screws.

Assembly Notes:

This is an easy cabinet to assemble and can be done a few different ways.  Believe it or not the panels go together so good that some people have assembled these just using masking tape to hold the panels together.  That's actually what they do in cabinet shops as well.  My directions probably make it sound a bit harder than it actually is, but once you have the panels laid out, you'll see how easy it can be done.  My directions assume you're using a wood glue like TiteBond, Elmers wood glue, or something similar. 

Assembly Tip: When clamping, you don't need to put lots of pressure on the panels, just enough to keep them from sliding around. 

Assembly Tip: Keep in mind that with any natural plywood, thickness can vary a little bit over the sheet.  Any variance on Baltic birch is usually around .01".  So, test fit your braces to be sure they fit in the rabbit joints okay.  If they seem overly tight, just a light sanding along the edge of the brace will be enough to get them to fit easier.  This is 100% normal with any type of plywood.

Assembly Tip: Rabbet joints are purposely cut about 1/64" bigger to allow for user error, slight shifting, excess wood glue, etc. while gluing them up.  Obviously this should be sanded off when your cabinet is completed.  I'd recommend some type of power sander to make the work much easier.

Assembly Tip: Sit the back panel up on something to keep it a few inches off your work bench.  This allows the head of your clamps to fit under the panel so you can clamp the other pieces to it much easier. 

I prefer to glue the braces in first. While clamping them down, make sure they stay between the rabbet joints cut around the rear panel and wipe away any glue that squishes into those grooves so the other panels will still lay in okay.  It's also important to glue them up as square as possible.  They don't have to be 100% perfect, but close.  After about 30 minutes, remove your clamps.  

Next you want to install the top and bottom pieces.  These also fit perfectly between the rabbet joints. Make sure you put glue where they touch the bracing.  Again, let the glue dry for at least 30 minutes before removing the clamps.

After you have the top and bottom on, I prefer to install just *one* side panel at a time.  I've seen people install both side panels at the same time but that will be harder to keep things lined up while clamping. 

Without adding glue, fit the remaining side panel in place.  Depending on how hard you clamped things down earlier, this could need to be tapped into place with a mallet, or a small block of wood and hammer.  Make note of where you need to apply the wood glue, remove the side panel, apply the wood glue where needed, then tap the panel back into place and clamp it down.

Last piece is the outer baffle.  Just put a bead of glue around the edges, then around the woofer cutout, then just drizzle it around the rest of the areas.  Lay the baffle on.  It will slide around a little bit, but don't worry.  Lightly tighten your clamps down while working your way around the box shifting the baffle into position.  If you have a small clamp, you can use it inside the woofer cutout to clamp the inner baffle to the outer baffle.  

Tips:

• Dry fit all pieces together first so you can see how the cabinet is suppose to assemble.
• Don't rush your build. Glue one or two panels at a time to make assembly accurate and easier.
• Use a quality wood glue and put a bead of it anywhere two panels touch.
• Clamp each panel for at least 30 minutes, then move to the next step. (depends on adhesive used)
• Don't over-clamp your panels.  Tighten your clamps enough to hold the panel in place.
• If you're going to add any filler to the seams, sand the edges down flush before adding filler.
• Predrill your woofer screw holes with a 7/64" or 1/8" drill bit.
• Protect your woofer when installing screws. You don't want the screw driver to slip and puncture the woofer!