The Shitbox build - 151db+ on one DC Lvl 5 18" @36hz!!!

[the_garynator]

Hard to see the flex in the video, but roof, windshield and sides of the car flex. Got the car pretty solid.

Got my eeepc back up and running, should have termlab numbers tomorrow! She's not completely broken in but seems to be getting pretty damned loud.

[the_garynator]

Glassed the bottom - should protect it a bit

glassed the top, not sure I'm liking how yellow it turned out, was hoping for it to be a little bit darker, but meh...we'll see how it turns out

Made a roundover plate for the interior

Cut the port down a bit (16.5" for 36hz)

Gave it a bit more room between the port exit and rear of the car

back and ready to go

I got my laptop back up and running and did a couple of burps prior to the modifications, but didn't hit anything special. Did a 150.0 with the door open, which is a bit lower than I had hoped, but considering that the 15" box had about 100hrs into it and was only about 1db louder, not to mention it had aero ports.

I was going to meter it again after the modifications but the termlab software wigged out, so I need to reinstall it. Hoping to get some more outta this thing, lot more work to do though.

[the_garynator]

Had some weird results when I metered the sub/box outside of the car to find out what the sub/box peak was. seemed to have two peaks, with the higher peak at 44hz and I thought the box was tuned to 36hz (where the smaller peak was). For further details on the issue, I posted the issue/question here: 156539-strange-enclosure-peak-frequencies-dc-audio-level-5-m1-18

Anyway, I figured I'd post the test results in here, either the modifications that I made since the initial test, or more likely, the controlled conditions of this test showed that the box did not, in fact, have two peaks, there was no dip after 36hz.

The thread did help in identifying that the box tuning calculator that I had been using was incorrect (weird thing is, it was fairly accurate when I used it for my 15" box, but that was with precision ports vs slotted). Either way the box is peaking at around 44hz, which is about 8hz higher than I had wanted. I'm going to build a different port and try to get closer to that 36hz I want and see how it goes.

And here's the test, I wanted a controlled test (would have been better to do it outside, but it was in the teens last night so I stayed inside my nice warm shop lol) to determine where the box/sub combo peaks in order to verify box tuning. **I know I know, this won't tell me where my in car peak will be, but I wanted to mimick my 15" box since I liked it, etc.**

Testing parameters:

• Port opening centered at the same spot for both boxes
  
• Term lab on the ground 8ft in front of port
  
• Car off
  
• 10 Amp charge from my car charger
  
• Remote Gain Knob at Max - Gain set with DD1 with head unit at volume 33 and Subwoofer level at +10
  
• Did 20-50hz sweep tone then 30-60hz for verification
  

I did not test individual frequencies because I had no time, as well as the fact that this is just to get an idea of where the peak is, once in the car, that's where I do the more in depth testing.

Testing the old Level 5 M1 15" in the old box

20-50hz sweep, volume at 20 of 33, subwoofer level at +7 of 10

30-60hz sweep, volume at 20 of 33, subwoofer level at +7 of 10

Close up of peak

Testing the new Level 5 M1 18" in the new box

20-50 sweep, volume at 20 of 33, subwoofer level at +7 of 10

30-60 sweep, volume at 20 of 33, subwoofer level at +7 of 10

Seems to be a second peak at 55hz too. 30-60 sweep, volume at 20 of 33, subwoofer level at +7 of 10

I did a couple of quick burps to get some idea of numbers.

• These were done with the car on, but the batteries were not topped off.
  
• Volume at 33 of 33 and Subwoofer level at +9 of 10
  

Driver Door open at the dash at 45hz, car on at 2000rpm

Sealed at the dash at 45hz, car on at 2000rpm

Sealed at the dash at 36hz, car on at 2000rpm

The peak in-car frequency may be different than 45hz but I didn't have time to test 43hz, 44hz, etc. It was getting late and the people next door to my shop don't appreciate me burping 150's after 10pm lol.

I'd be doing some more testing/modifying tonight, but I found I have a bad rear driver's side wheel bearing, so I'll be replacing that tonight and swapping some of the control arms/adjustment arms with the stock ones I pulled off of my white 240 (link to build thread in sig) which have bushings in much better condition. If I have time, I'll be swapping the drive shaft with a spare one I have laying around as well since the carrier bearing in the current one is shot.

I may pull the box and throw some more resin on it though as that won't take much time (gotta make it perty lol)

[the_garynator]

So things got a bit out of hand last night...I left work planning on swapping my driver's side rear suspension and being done for the night, but as happens fairly often to me, I start thinking and end up doing way more than planned.

My original plan earlier this year was to sand blast the replacement arms and paint them (for rust protection, I plan on pulling all of this stuff off of the car when she finally goes to the junk yard, so I didn't want them to get all rusty) when I had free time, then install them before winter. Well, no free time...so I started tearing into the car.

This is what it started as

I ended up deciding I really didn't like how yellow the resin made the birch look, I decided to sand off the layer of resin on the baffle so that I could stain it (my original plan for this box was to stain it, but after testing the resin on the bottom and thinking it looked better than it did, I resin'd the top). A friend of mine stopped out for a few hours and got about half the sanding done for me.

Everything removed. the brakes, axle and strut came out really easy, but I had to use heat and a breaker bar (don't have a pneumatic impact yet and my cordless didn't quite have the oomph) to get the bolts out of the traction rod, lower control arm, upper control arm and toe rod. It slowed me down quite a bit.

comparisons of the old vs the replacement (the one with the red on it) lower control arm / knuckle / hub assembly

The Rear tow arm bushing on the old one looked especially knarly. I noticed the same bushing on the replacement seems to have been replaced at some point, looks like it may be a polyurethane bushing (stock is rubber), but I didn't think to check the part number.

Top of picture: Rear Toe Arms (Top one is the replacement, bottom is the old one)

Bottom of picture: Rear Upper Control Arms (left is the old one, right is the replacement)

My buddy got half way done before he had to leave...so I took over, I was going for about 15-20 minutes at a time, then going back to working on the suspension to give the DA and Air Compressor a rest. At this point I realized that this wasn't going to be as easy as I had planned. 12 ounces of resin is A LOT to sand off, even with a DA and 80 grit. This was about the point that I decided to say screw it and paint the arms instead of just throwing them on.

I shot some degreaser on the arms and rinsed them off a few weeks ago, so all I did was go over them quick with a wire brush, then threw them in my sandblasting cabinet and did a quick once over to make a good surface for the paint to adhear to and get rid of any remaining rust or buildup. it went pretty quick for the traction rod and upper control arm, but when I got to the Toe arm, my gun started clogging up half way through...so I wrestled with it and finished up.

I then shot some plastikote metallic blue on them. Only reason I used it is because this was about the only quick drying paint I had on hand. I also did a quick once over on the strut with the wire brush and painted it the same color too...wasn't as good of a paint job as the arms, but I didn't have time to dick around disassembling it and my main goal was to slow the rust down.

While I was cleaning up the lower control arm / knuckle / hub assembly, I said screw it again and did a quick once over with the wire brush (would have blasted it, but didn't want to deal with having to tape off the wheel bearing and the possiblity of getting sand in it. Shot a quick coat of Krylon gloss black (literally only had enough to do one coat lol). dries to touch after 30min, can be handled in 2-3hrs iirc, but I didn't want to wait so I sped up the process by using my heat gun.

Here it is next to the old one...quite the difference, eh?

At this point it was getting to be around 5:30AM, decided enough dicking around and threw it back together...Thought I better make sure I have a driveable car seeing as how I had to work in under 4hrs.

During the reassembly I stained the box after I had done a quick once over with the DA sander using 120 grit. Stain color was Golden Pecan. It turned out pretty close to what I was hoping for. Can't wait to get a couple layers of resin over this, I'm pretty confident it will turn out looking like I want it too. Only thing I am a bit worried about is if it turns out too light, once the resin is on it, i'm not sanding it off to do another application of stain to darken it lol.

I'd test it on a spare piece but I don't have the patience to wait for a few more days before doing it. Maybe I'll only glass the front (the panel that faces the front of the car) tonight to see how it looks, then if I don't like it, you won't see it anyway, and maybe the port too, since I'll be replacing it to tune lower anyway.

Back in, thank goodness I decided to build this out of Baltic Birch...Even being 6cubes vs 3.9 and having a massive external slot port vs light aero ports, it weighs about the same as my 15" box. Also since the port is sturdy, it's easier to get out than the 15" box because i can lean the port against my stomach and grab onto the subwoofer opening. I'm sure if it was made out of MDF that I wouldn't be able to remove it and put it back in by myself lol.

This is what greeted me when I opened the garage door to my shop at 6:45AM...I ended up getting 1hr and 20min of sleep.

And to think, I'm planning on going back out to my shop after work tonight (g/f is out of town till tomorrow lol). I just hope I have enough strength left to pull the box out and I hope I can get the Torres calc working on my eeepc (it won't launch, throws an error...i'm thinking because I didn't have a chance to finish windows updates) so I can experiment with a smaller, lower tuned port.

If anyone wants to plug in some numbers into Torres for me tonight (I'm guessing I won't be able to get it up and running tonight lol) I'd be very grateful.

Box dimensions are here: http://www.stevemead...18/page__st__20

I want to tune to as close to 36hz as possible, but I'm limited to the port being external and cannot be any longer than 18"...The starting point I was planning on using once I get access to the calculator was going with a 3.5"h x 18.5"w x 16.5"L port to see where i'd be...reason being is that it would fit perfectly inside of the current opening vs bolting on the front. that cuts port surface area down about 35% from 100in^2 to 64.75in^2...was also considering trying a 3.5"h x 20"w x 16.5"L port.

If someone wanted to throw these numbers in and post the results as well as seeing if it's even feasible to tune at 36hz with an external straight port that'd be wonderful.

Another thing on the docket for tonight is doing some more metering!

[the_garynator]

Well, didn't really get much time to test, two of my friends ended up swinging by and we shot the shit most of the night. It ended up being another LONG night...didn't get home till 5:30AM. I was a real derp this morning and showed up to work only to find out that I had taken vacation today LOL.

Anyway, I laid resin over the front of the box to see whether or not I wanted to throw another coat of stain on. It turned out looking fantastic, exactly what I was hoping for. Since I have today off, I think I'm going to lay a coat or two on the baffle and if I have time, on the rear of the box too.

First medium (5-6 ounces of resin) coat laid (still wet in photo, but I'm hoping to be able to polish the baffle and rear (port side) to get a similar level of shine):

Second medium coat (7-8 ounces of resin) coat laid and dry:

I didn't get an entirely smooth finish (has some dips in it) but since this was just to see how it will look, and you won't see this part of the box for the most part, I didn't want to waste the resin to do a third thick coat. I'm also not going to spend the time to sand/polish it...I'd rather spend that time and effort getting the sides that show perfect.

I also decided to experiment with the port and make it a bit smaller. After not having time to meter it last night with after changing the port like I had planned, and having today off to get my eeepc working with Torres, I realize it was kinda worthless and I should have just waited to change the port until I had Torres working. Also, the fact that in my delerium from lack of sleep, I screwed up cutting the port panels and wasted a bunch of MDF and time lol.

Anyway, I'm hoping to do some more testing today, so I should have more termlab results posted later.

[FALLN]

love the look of the stained box!

[the_garynator]

love the look of the stained box!

Thanks man! Just wait till I finish glassing over it...I'm super pleased with how the baffle turned out! Pics will be up shortly.

[the_garynator]

Metered it with the new port modifications that were done in my previous post. The results were promising.

Much lower tuning...Torres said the tuning was around 31hz to 35hz depending on the length you put in..wasn't sure what the effective length was as there was a 3" section that was 5x20 on the inner section of the port, then it went to 3.5x18.5. Results seem to suggest that it was pretty accurate.

Testing conditions: Car on, drivers door open, at the dash

Laid a coat of resin (still wet in these two pictures) on the baffle. Put her on pretty thick for the first coat, 10-12 ounces mixed fairly hot (I usually keep my shop at around 65 degrees when i'm working on stuff otherwise I get hot, so resin doesn't like to harden very fast at that temp without loading on the hardener).

Tore her down and cut out the section that had the 3/4" MDF with the roundovered edges:

Kyle screwing together the new port assembly

The assembled port. The inner most layer of birch fits perfectly in the rectangular hole cut in the box. The next two layers are 2" wider and 1" taller which allows me to run screws along the sides and top to screw it to the front of the box. The bottom, inner piece lines up perfectly with the bottom of the box, so using the previous screw holes, that secures the bottom.

5/8" roundover around the inner port opening to help smooth air flow. My router's crappy base decided to drop the height a hair so I got a little lip, but I plan on doing some more sanding at a later time because I didn't have time to sand it last night.

port exit with 3/8" roundover. Will be doing more with this, but didn't have time and this does well enough until I have time to finish what I've got planned.

Port screwed onto the box

Taped up to seal...note: there didn't need to be this much tape, but I didn't glue the port together yet, so I taped off the seams where the pieces of the port meet just for the time being. once the port assembly has been glued together, all that will be needed for tape is a layer around the inner most layer that fits into the section of the box we cut out. forgot to get pictures of the internals before we taped it off, but it fits like a glove.

Final layer of resin on baffle dry. second layer was 12-14 ounces. used a roundover on the edges to get rid of the excess build up there. I love how this turned out. I can't wait to get the rest of the box coated then polish it. I'm hoping to get a very nice shine (so it looks similar to when it is wet).

back in

I did meter it quickly but forgot to take a picture. It did a 150.6 at 36hz with driver's door open, car on, at the dash. I noticed that it's a lot windier in the car and more violent in the lows. It seems to have a lot better frequency response and has more control on the lows. I have a few things I'm going to be trying and some tweaks I have to make yet, but I'm hoping to crack a 151 soon...I'm pretty sure it will do it without too much more effort unless there's something else holding me back (like a pressure related thing like a leak or something).

[the_garynator]

Time for an update.

Got two sheets of old rockford sound deadening for free from a friend, so I said, what the hell and threw it on the rear of the trunk (figured it'd help the most since the port fires right at it).

I metered it before and after adding this, it did somewhere around a 150.55. Here's what it did after. (Not sure this was all due to the deadener as my car isn't very consistant when going full tilt, numbers can go up or down about a tenth, but it didn't go down).

I finally got around to glassing the last side. Earlier in the week I did the port side of the box and one of the sides. I didn't upload pictures because I ran into an issue with the resin pulling away/cracking when I removed the block off plate and was rather frustrated.

I did a little to attempt to fix it but to get it to look right is probably going to require a full tear down and I'm not sure how much longer I'm going to run this box, so I'm holding off for a bit until I make a decision. If you don't look close, it doesn't look too bad though.

While the resin was drying, I decided to retape around the spare tire well cover to seal off the tire well.

I decided to give low tuning a shot and built a port baffle for my 3 4" precision ports from my old 15 box. This is about 1/2 the recommended port area for the box and tunes to right around 30hz according to Torres.

I got about 80% done with the last hole and my router finally took a crap I knew it was on its way out because it started spitting burnt chunks of plastic/paper out of it randomly starting about a week or two ago. Luckilly I only paid $35 for it from craigslist, it gives me a reason to get a nice fancy new one. It just sucks that I will be without a router for the next few weeks though

Mounted up. These ports look sooooo small on this box lol

Taped the gap.

Box back into car

Here's where things get interesting. I only seem to have lost about .6db at 36hz even after going from a 70sq in slot port which is ~11.7in^2/cube (12-16" recommended) to 6.28in^2 in round ports (10-12" recommended). Not to mention tuning 6hz lower.

I do have to say that it doesn't sound nearly as good compared to the slot port, it's lacking a lot of the punch and output in the higher frequencies, but that's exactly what I expected tuning this low with such low tuning. It does, however, cause a lot more flex at 32hz now than it did at 36hz with the slot port.

I did order 2 more 4" precision ports from parts express last night, I'd do larger, but since I already have 3 of them, it was the cheapest and easiest option at the moment. 6 inchers aren't really in my budget (would be like $120 for 3 of them!) and I'm following up some leads on getting some large metal bellmouth flares, but that may take a while to pan out if it ever does. 5 4" ports at the same length (15" effective) should give it a 10.5in^2/cube ratio and tune to around 37hz.

It did somewhere around a 147.8 at 30hz but I didn't grab a picture. Unfortunately I didn't test with the other port, but I'll probably be swapping back to it tonight if I end up going out to my shop, so I can see if it gained anything down there. I am also considering swapping the center sections of the ports to my short 6" sections (port flares are 3" each, current center sections are 9") to tune a bit higher to see what happens.

I also bought a 9"x33' roll of "peel and seal" (different brand though) today for $20. Before anyone gets all over me about it sucking, I did read up and researched it. for one I don't really care about getting rid of vibration. The main reason I'm doing it is to seal it up better, this thing is RUSTY. Hopefully this will help seal up any leaks (air AND water hahahaha). I may end up applying some of this tonight as well if I go out there.

Let me know what you think, I'm open to feedback!

[the_garynator]

Big update coming!!!! (as soon as I get the pictures/post together)