Box design help

skydeaner

Member
2020-02-28 1:46 am
I really suck at visualizing things. I work in a noc and am not dumb I just need help with things like this lol.

Can someone run a box design program and provide me the dimensions, cuts and number of 4ftx4ft baltic birch panels 3/4" I would need to for a 16"x16" footprint box. Subwoofer and slot port (full width, 1.5" thick for ease of using two sheets of birch for spacers) on one of the 16 x ? sides.

So it would look something like https://images-hpca.netdna-ssl.com/D.cache.dpthmbn/116/480.jpg

But I would have the port on the floor and it would be much taller I'm assuming (probably over 30" which i'm fine with)

I would like it to be 2.5 cubes internal volume, the driver displacement is roughly .25 cuft. I plan to put in one or two horizontal braces but will be more of a cross, so maybe subtract another .2 cubes for that?

i would like a tuning frequency of about 20hz. A little lower is fine, I would like the height to stay under 40" if it is possible to fit the port inside a 40" box.

I'm sorry to call on you my first post, but I've tried several of the online tools for this and I just can't get it to understand what I'm wanting and spit out measurements I need for my cuts. And the one I did get it to work on I don't trust and now can't find again and it still wouldn't tell me how many sheets I would need to complete this project.

And of course if you need more information from me please let me know.
 

skydeaner

Member
2020-02-28 1:46 am
So that is one of the ones I tried. But it won't let me let it determine the, what it calls, "width" by calculating after I put in a 16inch height it will only calculate the depth. also my ports always end up hanging out of the box.

If i just plan on putting the driver on a different side than it is telling me and just set the two dimensions I can to 16" and let it calculate what I will be using as the height, it still won't warp the port around a third wall and just hangs it out of the box.
Is there another tool online that works a little better?

I get this lol click to see the weird box

Also the website sometimes flags my connection and says I can't access it from the united states. I can run a vpn and get to it but I'm pretty sure it is russia being weird. The owner's name looks Russian and the whois goes back to ontario canada. Weird stuff.
 

skydeaner

Member
2020-02-28 1:46 am
Is it subtracting the airspace the port occupies even though it isn't showing it all inside the box in the picture? Cuz if I can just wrap it around in there without it doing so I think I can figure that out.

So internally I've got a 14.5x14.5x29.5=6202.375
Every inch of port is 14.5x2.25 so 52inches of that is 1696.5
4,506.875.. Is around 2.6 cubes. Minus driver Displacement. Maybe it is working right and I'll just adjust measurements for the last bend of the port but keep the same port length overall? Hrmm
 

skydeaner

Member
2020-02-28 1:46 am
I'm still deciding between a couple. They all model well in winisd in 2.5cubes at 22hz or 3 cubes at 18hz. So I want to kinda ballpark it in that range. Not going for perfection just somewhere close. I have modeled hundreds of drivers in winisd and am very familiar with it. Going to be under xmax anywhere in that range with the power I have available. I guess I'd prefer the lower tuning the better. I wish there were prefab enclosures tuned lower.
Getting a prefab of knockdown and modifying it with extra bracing and whatnot would be much less of a headache
 

skydeaner

Member
2020-02-28 1:46 am
I went out and bought 4 half sheets of mdf (just for ease of handling, the stuff is cheaper than I thought. I have a circular saw, jig saw, bought a router, Jasper jig, round over and flush cut bits for the port and laminate respectively.
Bought a kreg rip cut so I can cut straight with the circular saw without using boards/clamps cuz I'm lazy and want this to be my first of many speaker builds. I bought an nvx VCW122. It modeled really well in winisd for 3 cubes at 18 to 22 hz tuning. I have dual 40amp 12v server power supplies (free) that auto sense and distribute load when ran in parralel and of course have ov/oc/SC protection, and a 1000wrms car amp that I'm going to be running it all with until I can justify the price of a good 500+ watt amp with dsp. Benched the amp off those power supplies at about 500 wrms before clipping at only 12v. 15v would be ideal but the psus were free ninety nine lol.
So I have everything ready and will be posting build pics of the box soon assuming I don't screw something up along the way. I don't have a work table so I'm going to take a page out of someone's book I saw on YouTube and I bought a 2in thick 4x8 sheet of pink foam and will be laying the mdf on that for my cuts so I can just lay it down on my driveway to make the cuts.
So materials list so far.
NVX VCW122 12IN subwoofer.
(4)sheets of 3/4in mdf 4ftx4ft
4x8 sheet of 2in pink foam insulation
Power supplies
Amplifier
Liquid nails
Router
Jasper jig
Circular saw
Jig saw (might need it for cutting bracing materials)
Drywall screws
(Insert laminate here) probably just matte black
maybe this stuff?

And I think I'm all set.
I have built boxes in the past but they have always been rush jobs so I think I'm gonna take my time with this one and try to make it perfect.
I also have a belt sander, orbital sander, oscillating multitool, tons of other tools.
I feel like I'm missing something and I might start work on this as early as Tuesday, so fill in the blanks for me. And if anyone sees a good deal on a 500+wrms amp with dsp please link it. Like the crowns or behringer everyone has a boner for. Or I could just get a minidsp and stick with the car amp, it has always been good to me. I'm only pressurizing a small bedroom. And won't play it loud often but am tired of missing content in music/movies under 50hz.

Also, I haven't routered much. What size round over should I use for the flaring of the port on 3/4in mdf? Do I need a 3/4in roundover
.. Or just half that? Maybe I'll play with it tomorrow if I have time.
 

skydeaner

Member
2020-02-28 1:46 am
Welp. Got this finished up finally. I went with a 3000wrms amp for the beast. I need to gang in one or two more power supplies to drive it that hard though. And the driver only handles like 800 wrms, I just wanted the headroom.

So I have a TARAMPS HD3000 (check out the amp bench's on youtube, easily does 3000 watts at 14v)
Two 1100 watt Dell power supplies current sharing and strapped together with breakout boards running it. 89Adc each.
Mounted in a HTPC case, 4ga wiring.

The subwoofer itself. Turned out was a lot bigger project than I realized. The awesome laminate I got WOULD have turned out perfect but... The edges got ****** up. I was able to use a router and trim them (you would have to be braindead not to to be able to trim laminate correctly. And I was making fun of how much Lowes and custom cabinet shops charge lol.
Big mistake, I always screw myself over when I make fun of things being too easy.

So I spent all this money on everything and thought I had everything I needed, but to do the rough cuts on the laminate I needed to use a jigsaw (the only thing I used the jigsaw on for this entire project. Well the I picked the highest TPI blade I had, but I was cutting on foam (thank you youtuber that recommended this if you don't have a table saw, it was like cutting on a pillow of air) and the laminate was doing quite a bit of flapping up and down while I cut. Well it made little tears in the wood base of the laminate that allowed the glue to leak through and eat away the patter at the edges. If I would have trimmed the laminate about an inch bigger in every direction I wouldn't have had this problem. Or if I would have cut the laminate with a straight cut router bit or anything that wouldn't have been so rough on it.

Well here is a picture of what it looks like. It weighs about 140lb with the driver in it, I have since painted the port and ring around the driver black. I will be re laminating soon and getting better pictures. Also will probably round over the port. But then I'm not sure how I will cut the laminate in that area and I rarely have it up loud enough to hear port noise. Plus I have to corner load it in my room since it is like a 12ft cube. Or else I get nothing under 60hz at all.

Overall I am glad I did the project like this. I will get some pictures of the power supply/amp also.


49758475916_1e032fcf98_b.jpg

Tell me if this works or not, i've never used flickr and can't figure out how to have the forum host my picture lol


NOTE:
In the picture, the the edges are completely smooth, and absolutely perfect. The lightening you see is where the solvent in the glue ate through the pattern on the underfacing of the laminate. I'm not sure how to explain it.
 
20200529_175118 by skyler prahl, on Flickr

Here is a pic of the new laminate... It did the same thing on the edges with the glue unfortunately. I dunno.. I'm done.

I still need to get some black acrylic paint and trim the inside of the port and driver cutout. Hell maybe I will round them over to cover up the eaten away portion from the glue and just paint the whole roundover black.... I want to roundover the outside of the port anywhoser...



And a picture the measurements in room with calibrated mic(no room treatments).
I have an audu1701 dsp I am using for it to smooth out some of the wrinkles, but can someone help me understand the phase curve? The picture is with a crossover 4th order butterworth at 80hz, and the receivers 80hz high pass for my mains.
But the huge curve for the subwoofer phase... Is there a way to make that linear or is it normal for it to curve like that? (and my gain is set a little high on the sub i know, this is normal listening for me, not shooting for 100% linear)

plots by skyler prahl, on Flickr